Merge branch 'for-next/virtio'

35 files changed, 3675 insertions, 4 deletions

diff --git a/Documentation/user/user-manual.rst b/Documentation/user/user-manual.rst
index 827683eaa0..c80bfbf263 100644
--- a/Documentation/user/user-manual.rst
+++ b/Documentation/user/user-manual.rst
@@ -36,6 +36,7 @@ Contents:
    optee
    debugging
    watchdog
+   virtio
 
 * :ref:`search`
 * :ref:`genindex`
diff --git a/Documentation/user/virtio.rst b/Documentation/user/virtio.rst
new file mode 100644
index 0000000000..5d2a8c8208
--- /dev/null
+++ b/Documentation/user/virtio.rst
@@ -0,0 +1,82 @@
+..
+  SPDX-License-Identifier: GPL-2.0+
+
+  Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+  Copyright (C) 2021, Ahmad Fatoum
+
+.. _virtio:
+
+VirtIO Support
+==============
+
+This document describes the information about barebox support for VirtIO_
+devices, including supported boards, build instructions, driver details etc.
+
+What's VirtIO?
+--------------
+
+VirtIO is a virtualization standard for network and disk device drivers where
+just the guest's device driver "knows" it is running in a virtual environment,
+and cooperates with the hypervisor. This enables guests to get high performance
+network and disk operations, and gives most of the performance benefits of
+paravirtualization. In the barebox case, the guest is barebox itself, while the
+virtual environment will normally be QEMU_ targets like ARM, RISC-V and x86.
+
+Status
+------
+
+VirtIO can use various different buses, aka transports as described in the
+spec. While VirtIO devices are commonly implemented as PCI devices on x86,
+embedded devices models like ARM/RISC-V, which does not normally come with
+PCI support might use simple memory mapped device (MMIO) instead of the PCI
+device. The memory mapped virtio device behaviour is based on the PCI device
+specification. Therefore most operations including device initialization,
+queues configuration and buffer transfers are nearly identical. Only MMIO
+is currently supported in barebox.
+
+The VirtIO spec defines a lots of VirtIO device types, however at present only
+block, console and RNG devices are supported.
+
+Build Instructions
+------------------
+
+Building barebox for QEMU targets is no different from others.
+For example, we can do the following with the CROSS_COMPILE environment
+variable being properly set to a working toolchain for ARM::
+
+  $ make vexpress_defconfig
+  $ make
+
+Testing
+-------
+
+The following QEMU command line is used to get barebox up and running with
+a VirtIO console on ARM::
+
+  $ qemu-system-arm -m 256M -M virt -nographic             \
+  	-kernel ./images/barebox-dt-2nd.img                \
+  	-device virtio-serial-device                       \
+  	-chardev socket,path=/tmp/foo,server,nowait,id=foo \
+  	-device virtconsole,chardev=foo,name=console.foo
+
+To access the console socket, you can use ``socat /tmp/foo -``.
+
+Note the use of ``-kernel ./images/barebox-dt-2nd.img`` instead of
+``-bios ./images/barebox-$BOARD.img``. ``-kernel`` will cause QEMU
+to pass barebox a fixed-up device tree describing the ``virtio-mmio``
+rings.
+
+Except for the console, multiple instances of a VirtIO device can be created
+by appending more '-device' parameters. For example to create one HWRNG
+and 2 block devices::
+
+  $ qemu-system-arm -m 256M -M virt -nographic                  \
+    	-kernel ./images/barebox-dt-2nd.img                     \
+  	-device virtio-rng-device                               \
+  	-drive if=none,file=/tmp/first.hdimg,format=raw,id=hd0  \
+  	-device virtio-blk-device,drive=hd0		        \
+  	-drive if=none,file=/tmp/second.hdimg,format=raw,id=hd1 \
+  	-device virtio-blk-device,drive=hd1
+
+.. _VirtIO: http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf
+.. _qemu: https://www.qemu.org
diff --git a/Makefile b/Makefile
index 32d911ba78..6d44314f0a 100644
--- a/Makefile
+++ b/Makefile
@@ -408,13 +408,21 @@ LDFLAGS_MODULE  = -T common/module.lds
 # even be read-only.
 export MODVERDIR := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_versions
 
+# Use USERINCLUDE when you must reference the UAPI directories only.
+USERINCLUDE    := \
+		-I$(srctree)/arch/$(SRCARCH)/include/uapi \
+		-I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \
+		-I$(srctree)/include/uapi \
+		-I$(objtree)/include/generated/uapi \
+                -include $(srctree)/include/linux/kconfig.h
+
 # Use LINUXINCLUDE when you must reference the include/ directory.
 # Needed to be compatible with the O= option
 LINUXINCLUDE    := -Iinclude -I$(srctree)/dts/include \
                    $(if $(building_out_of_srctree), -I$(srctree)/include) \
 		   -I$(srctree)/arch/$(SRCARCH)/include \
 		   -I$(objtree)/arch/$(SRCARCH)/include \
-                   -include $(srctree)/include/linux/kconfig.h
+		   $(USERINCLUDE)
 
 KBUILD_CPPFLAGS        := -D__KERNEL__ -D__BAREBOX__ $(LINUXINCLUDE) -fno-builtin -ffreestanding
 
diff --git a/arch/arm/configs/vexpress_defconfig b/arch/arm/configs/vexpress_defconfig
index 760e39b440..d58ca7ebd0 100644
--- a/arch/arm/configs/vexpress_defconfig
+++ b/arch/arm/configs/vexpress_defconfig
@@ -1,6 +1,6 @@
 CONFIG_ARCH_VEXPRESS=y
-CONFIG_MACH_VIRT=y
 CONFIG_MACH_VEXPRESS=y
+CONFIG_MACH_VIRT=y
 CONFIG_AEABI=y
 CONFIG_ARM_OPTIMZED_STRING_FUNCTIONS=y
 CONFIG_MALLOC_SIZE=0x0
@@ -14,6 +14,9 @@ CONFIG_MENU=y
 CONFIG_BOOTM_SHOW_TYPE=y
 CONFIG_BOOTM_VERBOSE=y
 CONFIG_BOOTM_INITRD=y
+CONFIG_CONSOLE_ACTIVATE_ALL=y
+CONFIG_CONSOLE_ALLOW_COLOR=y
+CONFIG_PARTITION_DISK_EFI=y
 CONFIG_DEFAULT_ENVIRONMENT_GENERIC_NEW=y
 CONFIG_CMD_DMESG=y
 CONFIG_LONGHELP=y
@@ -28,6 +31,7 @@ CONFIG_CMD_PARTITION=y
 CONFIG_CMD_EXPORT=y
 CONFIG_CMD_PRINTENV=y
 CONFIG_CMD_SAVEENV=y
+CONFIG_CMD_FILETYPE=y
 CONFIG_CMD_UNCOMPRESS=y
 CONFIG_CMD_SLEEP=y
 CONFIG_CMD_DHCP=y
@@ -45,21 +49,28 @@ CONFIG_CMD_CRC=y
 CONFIG_CMD_CRC_CMP=y
 CONFIG_CMD_CLK=y
 CONFIG_CMD_DETECT=y
+CONFIG_CMD_POWEROFF=y
 CONFIG_CMD_OFTREE=y
 CONFIG_NET=y
 CONFIG_NET_NFS=y
 CONFIG_NET_NETCONSOLE=y
 CONFIG_OF_BAREBOX_DRIVERS=y
-CONFIG_OF_OVERLAY=y
 CONFIG_SERIAL_AMBA_PL011=y
+CONFIG_VIRTIO_CONSOLE=y
 CONFIG_DRIVER_NET_SMC91111=y
 # CONFIG_SPI is not set
 CONFIG_MTD=y
 CONFIG_MTD_CONCAT=y
 CONFIG_DRIVER_CFI=y
+CONFIG_VIRTIO_BLK=y
 CONFIG_MCI=y
 CONFIG_MCI_MMCI=y
+CONFIG_HWRNG=y
+CONFIG_HW_RANDOM_VIRTIO=y
 # CONFIG_PINCTRL is not set
+CONFIG_VIRTIO_MMIO=y
+CONFIG_FS_EXT4=y
 CONFIG_FS_TFTP=y
+CONFIG_FS_FAT=y
 CONFIG_DIGEST_SHA1_GENERIC=y
 CONFIG_DIGEST_SHA256_GENERIC=y
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 0b87c2af2a..787d366933 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -44,5 +44,6 @@ source "drivers/soc/imx/Kconfig"
 source "drivers/nvme/Kconfig"
 source "drivers/ddr/Kconfig"
 source "drivers/power/Kconfig"
+source "drivers/virtio/Kconfig"
 
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index fab3790288..be5b0b3b04 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -44,3 +44,4 @@ obj-y	+= nvme/
 obj-y	+= ddr/
 obj-y	+= power/
 obj-$(CONFIG_SOUND) += sound/
+obj-y	+= virtio/
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 040c5fd237..c0f0a3dbe3 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -16,6 +16,8 @@ config DISK_WRITE
 	select BLOCK_WRITE
 	bool "support writing to disk drives"
 
+source "drivers/block/Kconfig"
+
 comment "drive types"
 
 config DISK_BIOS
diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 6763bbc6f5..f60533c59e 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -102,7 +102,10 @@ int device_probe(struct device_d *dev)
 	list_del(&dev->active);
 	INIT_LIST_HEAD(&dev->active);
 
-	dev_err(dev, "probe failed: %s\n", strerror(-ret));
+	if (ret == -ENODEV || ret == -ENXIO)
+		dev_dbg(dev, "probe failed: %s\n", strerror(-ret));
+	else
+		dev_err(dev, "probe failed: %s\n", strerror(-ret));
 
 	return ret;
 }
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
new file mode 100644
index 0000000000..b42571eca5
--- /dev/null
+++ b/drivers/block/Kconfig
@@ -0,0 +1,6 @@
+config VIRTIO_BLK
+        bool "Virtio block driver"
+        depends on VIRTIO
+        help
+          This is the virtual block driver for virtio.  It can be used with
+          QEMU based VMMs (like KVM or Xen).
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 8812c0faec..23d634f006 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_EFI_BOOTUP) += efi-block-io.o
+obj-$(CONFIG_VIRTIO_BLK) += virtio_blk.o
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
new file mode 100644
index 0000000000..b7a83cf686
--- /dev/null
+++ b/drivers/block/virtio_blk.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <block.h>
+#include <disks.h>
+#include <linux/virtio_types.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ring.h>
+#include <uapi/linux/virtio_blk.h>
+
+struct virtio_blk_priv {
+	struct virtqueue *vq;
+	struct virtio_device *vdev;
+	struct block_device blk;
+};
+
+static int virtio_blk_do_req(struct virtio_blk_priv *priv, void *buffer,
+			     sector_t sector, blkcnt_t blkcnt, u32 type)
+{
+	unsigned int num_out = 0, num_in = 0;
+	struct virtio_sg *sgs[3];
+	u8 status;
+	int ret;
+
+	struct virtio_blk_outhdr out_hdr = {
+		.type = cpu_to_virtio32(priv->vdev, type),
+		.sector = cpu_to_virtio64(priv->vdev, sector),
+	};
+	struct virtio_sg hdr_sg = { &out_hdr, sizeof(out_hdr) };
+	struct virtio_sg data_sg = { buffer, blkcnt * 512 };
+	struct virtio_sg status_sg = { &status, sizeof(status) };
+
+	sgs[num_out++] = &hdr_sg;
+
+	switch(type) {
+	case VIRTIO_BLK_T_OUT:
+		sgs[num_out++] = &data_sg;
+		break;
+	case VIRTIO_BLK_T_IN:
+		sgs[num_out + num_in++] = &data_sg;
+		break;
+	}
+
+	sgs[num_out + num_in++] = &status_sg;
+
+	ret = virtqueue_add(priv->vq, sgs, num_out, num_in);
+	if (ret)
+		return ret;
+
+	virtqueue_kick(priv->vq);
+
+	while (!virtqueue_get_buf(priv->vq, NULL))
+		;
+
+	return status == VIRTIO_BLK_S_OK ? 0 : -EIO;
+}
+
+static int virtio_blk_read(struct block_device *blk, void *buffer,
+			   sector_t start, blkcnt_t blkcnt)
+{
+	struct virtio_blk_priv *priv = container_of(blk, struct virtio_blk_priv, blk);
+	return virtio_blk_do_req(priv, buffer, start, blkcnt,
+				 VIRTIO_BLK_T_IN);
+}
+
+static int virtio_blk_write(struct block_device *blk, const void *buffer,
+			    sector_t start, blkcnt_t blkcnt)
+{
+	struct virtio_blk_priv *priv = container_of(blk, struct virtio_blk_priv, blk);
+	return virtio_blk_do_req(priv, (void *)buffer, start, blkcnt,
+				 VIRTIO_BLK_T_OUT);
+}
+
+static struct block_device_ops virtio_blk_ops = {
+	.read	= virtio_blk_read,
+	.write	= virtio_blk_write,
+};
+
+static int virtio_blk_probe(struct virtio_device *vdev)
+{
+	struct virtio_blk_priv *priv;
+	u64 cap;
+	int devnum;
+	int ret;
+
+	priv = xzalloc(sizeof(*priv));
+
+	ret = virtio_find_vqs(vdev, 1, &priv->vq);
+	if (ret)
+		return ret;
+
+	priv->vdev = vdev;
+
+	devnum = cdev_find_free_index("virtioblk");
+	priv->blk.cdev.name = xasprintf("virtioblk%d", devnum);
+	priv->blk.dev = &vdev->dev;
+	priv->blk.blockbits = SECTOR_SHIFT;
+	virtio_cread(vdev, struct virtio_blk_config, capacity, &cap);
+	priv->blk.num_blocks = cap;
+	priv->blk.ops = &virtio_blk_ops;
+
+	ret = blockdevice_register(&priv->blk);
+	if (ret)
+		return ret;
+
+	parse_partition_table(&priv->blk);
+
+	return 0;
+}
+
+static void virtio_blk_remove(struct virtio_device *vdev)
+{
+	vdev->config->reset(vdev);
+	vdev->config->del_vqs(vdev);
+}
+
+static const struct virtio_device_id id_table[] = {
+        { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
+        { 0 },
+};
+
+static struct virtio_driver virtio_blk = {
+        .driver.name	= "virtio_blk",
+        .id_table	= id_table,
+        .probe		= virtio_blk_probe,
+	.remove		= virtio_blk_remove,
+};
+device_virtio_driver(virtio_blk);
diff --git a/drivers/hw_random/Kconfig b/drivers/hw_random/Kconfig
index 1923c755db..a84c03efef 100644
--- a/drivers/hw_random/Kconfig
+++ b/drivers/hw_random/Kconfig
@@ -29,4 +29,11 @@ config HWRNG_DEV_RANDOM
 	  This driver allows use of the host provided /dev/urandom
 	  as barebox HWRNGs.
 
+config HW_RANDOM_VIRTIO
+	tristate "VirtIO Random Number Generator support"
+	depends on VIRTIO
+	help
+	  This driver provides guest-side support for the virtual Random Number
+	  Generator hardware.
+
 endif
diff --git a/drivers/hw_random/Makefile b/drivers/hw_random/Makefile
index 2e318be738..4bab3967fc 100644
--- a/drivers/hw_random/Makefile
+++ b/drivers/hw_random/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_HWRNG)		+= core.o
 obj-$(CONFIG_HWRNG_MXC_RNGC) += mxc-rngc.o
 obj-$(CONFIG_HWRNG_STM32) += stm32-rng.o
 obj-$(CONFIG_HWRNG_DEV_RANDOM) += dev-random.o
+obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
diff --git a/drivers/hw_random/virtio-rng.c b/drivers/hw_random/virtio-rng.c
new file mode 100644
index 0000000000..fbf1a5715a
--- /dev/null
+++ b/drivers/hw_random/virtio-rng.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Randomness driver for virtio
+ *  Copyright (C) 2007, 2008 Rusty Russell IBM Corporation
+ */
+
+#include <common.h>
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/spinlock.h>
+#include <linux/virtio.h>
+#include <linux/virtio_rng.h>
+#include <linux/virtio_ring.h>
+#include <module.h>
+#include <linux/slab.h>
+
+#define BUFFER_SIZE		16UL
+
+struct virtrng_info {
+	struct hwrng hwrng;
+	char name[25];
+	struct virtqueue *rng_vq;
+	bool hwrng_register_done;
+};
+
+static inline struct virtrng_info *to_virtrng_info(struct hwrng *hwrng)
+{
+	return container_of(hwrng, struct virtrng_info, hwrng);
+}
+
+static int virtio_rng_read(struct hwrng *hwrng, void *data, size_t len, bool wait)
+{
+	int ret;
+	unsigned int rsize;
+	unsigned char buf[BUFFER_SIZE] __aligned(4);
+	unsigned char *ptr = data;
+	struct virtio_sg sg;
+	struct virtio_sg *sgs[1];
+	struct virtrng_info *vi = to_virtrng_info(hwrng);
+	size_t remaining = len;
+
+	while (remaining) {
+		sg.addr = buf;
+		sg.length = min(remaining, sizeof(buf));
+		sgs[0] = &sg;
+
+		ret = virtqueue_add(vi->rng_vq, sgs, 0, 1);
+		if (ret)
+			return ret;
+
+		virtqueue_kick(vi->rng_vq);
+
+		while (!virtqueue_get_buf(vi->rng_vq, &rsize))
+			;
+
+		memcpy(ptr, buf, rsize);
+		remaining -= rsize;
+		ptr += rsize;
+	}
+
+	return len;
+}
+
+static int probe_common(struct virtio_device *vdev)
+{
+	struct virtrng_info *vi;
+
+	vi = xzalloc(sizeof(*vi));
+
+	vi->hwrng.name = vdev->dev.name;
+	vi->hwrng.read = virtio_rng_read;
+
+	vdev->priv = vi;
+
+	/* We expect a single virtqueue. */
+	return virtio_find_vqs(vdev, 1, &vi->rng_vq);
+}
+
+static void remove_common(struct virtio_device *vdev)
+{
+	vdev->config->reset(vdev);
+	vdev->config->del_vqs(vdev);
+}
+
+static int virtrng_probe(struct virtio_device *vdev)
+{
+	return probe_common(vdev);
+}
+
+static void virtrng_remove(struct virtio_device *vdev)
+{
+	remove_common(vdev);
+}
+
+static void virtrng_scan(struct virtio_device *vdev)
+{
+	struct virtrng_info *vi = vdev->priv;
+	int err;
+
+	err = hwrng_register(&vdev->dev, &vi->hwrng);
+	if (!err)
+		vi->hwrng_register_done = true;
+}
+
+static const struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_RNG, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct virtio_driver virtio_rng_driver = {
+	.driver.name =	"virtio-rng",
+	.id_table =	id_table,
+	.probe =	virtrng_probe,
+	.remove =	virtrng_remove,
+	.scan =		virtrng_scan,
+};
+
+module_virtio_driver(virtio_rng_driver);
+MODULE_DESCRIPTION("Virtio random number driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 5c6f0e88e3..09434c1ba8 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -156,4 +156,12 @@ config DRIVER_SERIAL_LPUART
 	default y
 	bool "LPUART serial driver"
 
+config VIRTIO_CONSOLE
+	tristate "Virtio console"
+	select VIRTIO
+	help
+	  Virtio console for use with hypervisors.
+
+	  Also serves as a general-purpose serial device for data
+	  transfer between the guest and host.
 endmenu
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 8a2abbbe45..7ff41cd5c7 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_DRIVER_SERIAL_CADENCE)		+= serial_cadence.o
 obj-$(CONFIG_DRIVER_SERIAL_EFI_STDIO)		+= efi-stdio.o
 obj-$(CONFIG_DRIVER_SERIAL_DIGIC)		+= serial_digic.o
 obj-$(CONFIG_DRIVER_SERIAL_LPUART)		+= serial_lpuart.o
+obj-$(CONFIG_VIRTIO_CONSOLE)			+= virtio_console.o
diff --git a/drivers/serial/virtio_console.c b/drivers/serial/virtio_console.c
new file mode 100644
index 0000000000..a1331035d9
--- /dev/null
+++ b/drivers/serial/virtio_console.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
+ * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
+ * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
+ * Copyright (C) 2021 Ahmad Fatoum
+ *
+ * This ridiculously simple implementation does a DMA transfer for
+ * every single character. On the plus side, we neither need to
+ * buffer RX or to wade through TX to turn LFs to CRLFs.
+ */
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+#include <linux/list.h>
+#include <malloc.h>
+#include <console.h>
+#include <xfuncs.h>
+#include <linux/spinlock.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ring.h>
+#include <linux/virtio_console.h>
+
+struct virtio_console {
+	struct console_device cdev;
+	struct virtqueue *in_vq, *out_vq;
+	char inbuf[1];
+};
+
+static bool have_one;
+
+/*
+ * The put_chars() callback is pretty straightforward.
+ *
+ * We turn the characters into a scatter-gather list, add it to the
+ * output queue and then kick the Host.  Then we sit here waiting for
+ * it to finish: inefficient in theory, but in practice
+ * implementations will do it immediately (lguest's Launcher does).
+ */
+static void put_chars(struct virtio_console *virtcons, const char *buf, int count)
+{
+	struct virtqueue *out_vq = virtcons->out_vq;
+	unsigned int len;
+	struct virtio_sg *sgs[1] = {
+		&(struct virtio_sg) { .addr = (void *)buf, .length = count }
+	};
+
+	/*
+	 * add_buf wants a token to identify this buffer: we hand it
+	 * any non-NULL pointer, since there's only ever one buffer.
+	 */
+	if (virtqueue_add(out_vq, sgs, 1, 0) >= 0) {
+		/* Tell Host to go! */
+		virtqueue_kick(out_vq);
+		/* Chill out until it's done with the buffer. */
+		while (!virtqueue_get_buf(out_vq, &len))
+			cpu_relax();
+	}
+}
+
+static void virtcons_putc(struct console_device *cdev, char c)
+{
+	struct virtio_console *virtcons = container_of(cdev, struct virtio_console, cdev);
+
+	return put_chars(virtcons, &c, 1);
+}
+
+/*
+ * Create a scatter-gather list representing our input buffer and put
+ * it in the queue.
+ */
+static void add_inbuf(struct virtio_console *virtcons)
+{
+	struct virtio_sg *sgs[1] = { &(struct virtio_sg) {
+		.addr = virtcons->inbuf, .length = sizeof(virtcons->inbuf) }
+	};
+
+	/* We should always be able to add one buffer to an empty queue. */
+	if (virtqueue_add(virtcons->in_vq, sgs, 0, 1) < 0)
+		BUG();
+	virtqueue_kick(virtcons->in_vq);
+}
+
+static int virtcons_tstc(struct console_device *cdev)
+{
+	struct virtio_console *virtcons = container_of(cdev, struct virtio_console, cdev);
+
+	return virtqueue_poll(virtcons->in_vq, virtcons->in_vq->last_used_idx);
+}
+
+static int virtcons_getc(struct console_device *cdev)
+{
+	struct virtio_console *virtcons = container_of(cdev, struct virtio_console, cdev);
+	char *in;
+	int ch;
+
+	in = virtqueue_get_buf(virtcons->in_vq, NULL);
+	if (!in)
+		BUG();
+
+	ch = *in;
+
+	add_inbuf(virtcons);
+
+	return ch;
+}
+
+static int virtcons_probe(struct virtio_device *vdev)
+{
+	struct virtqueue *vqs[2];
+	struct virtio_console *virtcons;
+	int err;
+
+	if (have_one) {
+		/* Neither multiport consoles (one virtio_device for multiple consoles)
+		 * nor multiple consoles (one virtio_device per each console
+		 * is supported. I would've expected:
+		 *   -chardev socket,path=/tmp/bar,server,nowait,id=bar \
+		 *   -device virtconsole,chardev=bar,name=console.bar \
+		 *   -device virtio-serial-device \
+		 *   -chardev socket,path=/tmp/baz,server,nowait,id=baz \
+		 *   -device virtconsole,chardev=baz,name=console.baz \
+		 * to just work, but it doesn't
+		 */
+		dev_warn(&vdev->dev,
+			 "Multiple virtio-console devices not supported yet\n");
+		return -EEXIST;
+	}
+
+	/* Find the queues. */
+	err = virtio_find_vqs(vdev, 2, vqs);
+	if (err)
+		return err;
+
+	virtcons = xzalloc(sizeof(*virtcons));
+
+	virtcons->in_vq = vqs[0];
+	virtcons->out_vq = vqs[1];
+
+	/* Register the input buffer the first time. */
+	add_inbuf(virtcons);
+
+	virtcons->cdev.dev = &vdev->dev;
+	virtcons->cdev.tstc = virtcons_tstc;
+	virtcons->cdev.getc = virtcons_getc;
+	virtcons->cdev.putc = virtcons_putc;
+
+	have_one = true;
+
+	return console_register(&virtcons->cdev);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct virtio_driver virtio_console = {
+	.driver.name =	"virtio_console",
+	.id_table =	id_table,
+	.probe =	virtcons_probe,
+};
+device_virtio_driver(virtio_console);
+
+MODULE_DESCRIPTION("Virtio console driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
new file mode 100644
index 0000000000..59e3d3c3f5
--- /dev/null
+++ b/drivers/virtio/Kconfig
@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config VIRTIO
+	bool
+	help
+	  This option is selected by any driver which implements the virtio
+	  bus, such as CONFIG_VIRTIO_MMIO.
+
+config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+	bool
+	help
+	  This option is selected if the architecture may need to enforce
+	  VIRTIO_F_ACCESS_PLATFORM
+
+menuconfig VIRTIO_MENU
+	bool "Virtio drivers"
+	default y
+
+if VIRTIO_MENU
+
+config VIRTIO_MMIO
+	bool "Platform bus driver for memory mapped virtio devices"
+	depends on HAS_DMA
+	select VIRTIO
+	help
+	 This drivers provides support for memory mapped virtio
+	 platform device driver. This is usually used with Qemu.
+
+endif # VIRTIO_MENU
diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
new file mode 100644
index 0000000000..94ff1398fb
--- /dev/null
+++ b/drivers/virtio/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o
+obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
new file mode 100644
index 0000000000..c96c465e87
--- /dev/null
+++ b/drivers/virtio/virtio.c
@@ -0,0 +1,347 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <common.h>
+#include <linux/virtio.h>
+#include <linux/spinlock.h>
+#include <linux/virtio_config.h>
+#include <module.h>
+#include <linux/kernel.h>
+#include <uapi/linux/virtio_ids.h>
+
+static int status_show(struct param_d *param, void *_dev)
+{
+	struct virtio_device *dev = _dev;
+
+	dev->status_param = dev->config->get_status(dev);
+	return 0;
+}
+
+static struct param_d *virtio_dev_add_param_features(struct virtio_device *dev)
+{
+	struct param_d *param;
+	unsigned int i;
+	char *buf;
+	int len = 0;
+
+	buf = xmalloc(sizeof(dev->features)*8 + 1);
+
+	/* We actually represent this as a bitstring, as it could be
+	 * arbitrary length in future. */
+	for (i = 0; i < sizeof(dev->features)*8; i++)
+		len += sprintf(buf+len, "%c",
+			       __virtio_test_bit(dev, i) ? '1' : '0');
+
+	param = dev_add_param_string_fixed(&dev->dev, "features", buf);
+	free(buf);
+
+	return param;
+}
+
+static inline int virtio_id_match(const struct virtio_device *dev,
+				  const struct virtio_device_id *id)
+{
+	if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
+		return 0;
+
+	return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
+}
+
+/* This looks through all the IDs a driver claims to support.  If any of them
+ * match, we return 1 and the kernel will call virtio_dev_probe(). */
+static int virtio_dev_match(struct device_d *_dv, struct driver_d *_dr)
+{
+	unsigned int i;
+	struct virtio_device *dev = dev_to_virtio(_dv);
+	const struct virtio_device_id *ids;
+
+	ids = drv_to_virtio(_dr)->id_table;
+	for (i = 0; ids[i].device; i++)
+		if (virtio_id_match(dev, &ids[i]))
+			return 0;
+
+	return -1;
+}
+
+void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
+					 unsigned int fbit)
+{
+	unsigned int i;
+	struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
+
+	for (i = 0; i < drv->feature_table_size; i++)
+		if (drv->feature_table[i] == fbit)
+			return;
+
+	if (drv->feature_table_legacy) {
+		for (i = 0; i < drv->feature_table_size_legacy; i++)
+			if (drv->feature_table_legacy[i] == fbit)
+				return;
+	}
+
+	BUG();
+}
+EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
+
+static void __virtio_config_changed(struct virtio_device *dev)
+{
+	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+
+	if (!dev->config_enabled)
+		dev->config_change_pending = true;
+	else if (drv && drv->config_changed)
+		drv->config_changed(dev);
+}
+
+void virtio_config_changed(struct virtio_device *dev)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->config_lock, flags);
+	__virtio_config_changed(dev);
+	spin_unlock_irqrestore(&dev->config_lock, flags);
+}
+EXPORT_SYMBOL_GPL(virtio_config_changed);
+
+void virtio_config_disable(struct virtio_device *dev)
+{
+	dev->config_enabled = false;
+}
+EXPORT_SYMBOL_GPL(virtio_config_disable);
+
+void virtio_config_enable(struct virtio_device *dev)
+{
+	dev->config_enabled = true;
+	if (dev->config_change_pending)
+		__virtio_config_changed(dev);
+	dev->config_change_pending = false;
+}
+EXPORT_SYMBOL_GPL(virtio_config_enable);
+
+void virtio_add_status(struct virtio_device *dev, unsigned int status)
+{
+	dev->config->set_status(dev, dev->config->get_status(dev) | status);
+}
+EXPORT_SYMBOL_GPL(virtio_add_status);
+
+int virtio_finalize_features(struct virtio_device *dev)
+{
+	int ret = dev->config->finalize_features(dev);
+	unsigned status;
+
+	if (ret)
+		return ret;
+
+	ret = arch_has_restricted_virtio_memory_access();
+	if (ret) {
+		if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
+			dev_warn(&dev->dev,
+				 "device must provide VIRTIO_F_VERSION_1\n");
+			return -ENODEV;
+		}
+
+		if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
+			dev_warn(&dev->dev,
+				 "device must provide VIRTIO_F_ACCESS_PLATFORM\n");
+			return -ENODEV;
+		}
+	}
+
+	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
+		return 0;
+
+	virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
+	status = dev->config->get_status(dev);
+	if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
+		dev_err(&dev->dev, "virtio: device refuses features: %x\n",
+			status);
+		return -ENODEV;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_finalize_features);
+
+int virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
+		    struct virtqueue *vqs[])
+{
+	return vdev->config->find_vqs(vdev, nvqs, vqs);
+}
+EXPORT_SYMBOL_GPL(virtio_find_vqs);
+
+static int virtio_dev_probe(struct device_d *_d)
+{
+	int err, i;
+	struct virtio_device *dev = dev_to_virtio(_d);
+	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+	u64 device_features;
+	u64 driver_features;
+	u64 driver_features_legacy;
+
+	/* We have a driver! */
+	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
+
+	/* Figure out what features the device supports. */
+	device_features = dev->config->get_features(dev);
+
+	/* Figure out what features the driver supports. */
+	driver_features = 0;
+	for (i = 0; i < drv->feature_table_size; i++) {
+		unsigned int f = drv->feature_table[i];
+		BUG_ON(f >= 64);
+		driver_features |= (1ULL << f);
+	}
+
+	/* Some drivers have a separate feature table for virtio v1.0 */
+	if (drv->feature_table_legacy) {
+		driver_features_legacy = 0;
+		for (i = 0; i < drv->feature_table_size_legacy; i++) {
+			unsigned int f = drv->feature_table_legacy[i];
+			BUG_ON(f >= 64);
+			driver_features_legacy |= (1ULL << f);
+		}
+	} else {
+		driver_features_legacy = driver_features;
+	}
+
+	if (device_features & (1ULL << VIRTIO_F_VERSION_1))
+		dev->features = driver_features & device_features;
+	else
+		dev->features = driver_features_legacy & device_features;
+
+	/* Transport features always preserved to pass to finalize_features. */
+	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
+		if (device_features & (1ULL << i))
+			__virtio_set_bit(dev, i);
+
+	if (drv->validate) {
+		err = drv->validate(dev);
+		if (err)
+			goto err;
+	}
+
+	err = virtio_finalize_features(dev);
+	if (err)
+		goto err;
+
+	err = drv->probe(dev);
+	if (err)
+		goto err;
+
+	/* If probe didn't do it, mark device DRIVER_OK ourselves. */
+	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
+		virtio_device_ready(dev);
+
+	if (drv->scan)
+		drv->scan(dev);
+
+	virtio_config_enable(dev);
+
+	return 0;
+err:
+	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
+	return err;
+
+}
+
+static void virtio_dev_remove(struct device_d *_d)
+{
+	struct virtio_device *dev = dev_to_virtio(_d);
+	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+
+	virtio_config_disable(dev);
+
+	drv->remove(dev);
+
+	WARN_ONCE(dev->config->get_status(dev), "Driver should have reset device");
+
+	/* Acknowledge the device's existence again. */
+	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+}
+
+static struct bus_type virtio_bus = {
+	.name  = "virtio",
+	.match = virtio_dev_match,
+	.probe = virtio_dev_probe,
+	.remove = virtio_dev_remove,
+};
+
+int virtio_driver_register(struct virtio_driver *driver)
+{
+	/* Catch this early. */
+	BUG_ON(driver->feature_table_size && !driver->feature_table);
+	driver->driver.bus = &virtio_bus;
+
+	return register_driver(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(virtio_driver_register);
+
+/**
+ * register_virtio_device - register virtio device
+ * @dev        : virtio device to be registered
+ *
+ * On error, the caller must call put_device on &@dev->dev (and not kfree),
+ * as another code path may have obtained a reference to @dev.
+ *
+ * Returns: 0 on suceess, -error on failure
+ */
+int register_virtio_device(struct virtio_device *dev)
+{
+	int err;
+
+	dev->dev.bus = &virtio_bus;
+	dev->dev.id = DEVICE_ID_DYNAMIC;
+	dev->dev.name = "virtio";
+
+	spin_lock_init(&dev->config_lock);
+	dev->config_enabled = false;
+	dev->config_change_pending = false;
+
+	/* We always start by resetting the device, in case a previous
+	 * driver messed it up.  This also tests that code path a little. */
+	dev->config->reset(dev);
+
+	/* Acknowledge that we've seen the device. */
+	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+
+	INIT_LIST_HEAD(&dev->vqs);
+
+	/*
+	 * register_device() causes the bus infrastructure to look for a matching
+	 * driver.
+	 */
+	err = register_device(&dev->dev);
+	if (err)
+		goto out;
+
+	dev_add_param_uint32_ro(&dev->dev, "device", &dev->id.device, "0x%04x");
+	dev_add_param_uint32_ro(&dev->dev, "vendor", &dev->id.vendor, "0x%04x");
+	dev_add_param_uint32(&dev->dev, "status", param_set_readonly,
+			     status_show, &dev->status_param, "0x%08x", dev);
+	virtio_dev_add_param_features(dev);
+
+out:
+	if (err)
+		virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
+	return err;
+}
+EXPORT_SYMBOL_GPL(register_virtio_device);
+
+bool is_virtio_device(struct device_d *dev)
+{
+	return dev->bus == &virtio_bus;
+}
+EXPORT_SYMBOL_GPL(is_virtio_device);
+
+void unregister_virtio_device(struct virtio_device *dev)
+{
+	unregister_device(&dev->dev);
+}
+EXPORT_SYMBOL_GPL(unregister_virtio_device);
+
+static int virtio_init(void)
+{
+	if (bus_register(&virtio_bus) != 0)
+		panic("virtio bus registration failed");
+	return 0;
+}
+core_initcall(virtio_init);
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
new file mode 100644
index 0000000000..821b43871a
--- /dev/null
+++ b/drivers/virtio/virtio_mmio.c
@@ -0,0 +1,465 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Virtio memory mapped device driver
+ *
+ * Copyright 2011-2014, ARM Ltd.
+ *
+ * This module allows virtio devices to be used over a virtual, memory mapped
+ * platform device.
+ *
+ * The guest device(s) may be instantiated via Device Tree node, eg.:
+ *
+ *		virtio_block@1e000 {
+ *			compatible = "virtio,mmio";
+ *			reg = <0x1e000 0x100>;
+ *			interrupts = <42>;
+ *		}
+ *
+ * Qemu will automatically fix up the nodes corresponding to its command line
+ * arguments into the barebox device tree.
+ *
+ * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
+ */
+
+#define pr_fmt(fmt) "virtio-mmio: " fmt
+
+#include <common.h>
+#include <io.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <driver.h>
+#include <linux/slab.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <uapi/linux/virtio_mmio.h>
+#include <linux/virtio_ring.h>
+
+#define to_virtio_mmio_device(_plat_dev) \
+	container_of(_plat_dev, struct virtio_mmio_device, vdev)
+
+#define VIRTIO_MMIO_VRING_ALIGN		PAGE_SIZE
+
+struct virtio_mmio_device {
+	struct virtio_device vdev;
+
+	void __iomem *base;
+	unsigned long version;
+};
+
+struct virtio_mmio_vq_info {
+	/* the actual virtqueue */
+	struct virtqueue *vq;
+};
+
+static int virtio_mmio_get_config(struct virtio_device *vdev, unsigned int offset,
+				  void *buf, unsigned int len)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+	void __iomem *base = priv->base + VIRTIO_MMIO_CONFIG;
+	u8 b;
+	__le16 w;
+	__le32 l;
+
+	if (priv->version == 1) {
+		u8 *ptr = buf;
+		int i;
+
+		for (i = 0; i < len; i++)
+			ptr[i] = readb(base + offset + i);
+
+		return 0;
+	}
+
+	switch (len) {
+	case 1:
+		b = readb(base + offset);
+		memcpy(buf, &b, sizeof(b));
+		break;
+	case 2:
+		w = cpu_to_le16(readw(base + offset));
+		memcpy(buf, &w, sizeof(w));
+		break;
+	case 4:
+		l = cpu_to_le32(readl(base + offset));
+		memcpy(buf, &l, sizeof(l));
+		break;
+	case 8:
+		l = cpu_to_le32(readl(base + offset));
+		memcpy(buf, &l, sizeof(l));
+		l = cpu_to_le32(readl(base + offset + sizeof(l)));
+		memcpy(buf + sizeof(l), &l, sizeof(l));
+		break;
+	default:
+		WARN_ON(true);
+	}
+
+	return 0;
+}
+
+static int virtio_mmio_set_config(struct virtio_device *vdev, unsigned int offset,
+				  const void *buf, unsigned int len)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+	void __iomem *base = priv->base + VIRTIO_MMIO_CONFIG;
+	u8 b;
+	__le16 w;
+	__le32 l;
+
+	if (priv->version == 1) {
+		const u8 *ptr = buf;
+		int i;
+
+		for (i = 0; i < len; i++)
+			writeb(ptr[i], base + offset + i);
+
+		return 0;
+	}
+
+	switch (len) {
+	case 1:
+		memcpy(&b, buf, sizeof(b));
+		writeb(b, base + offset);
+		break;
+	case 2:
+		memcpy(&w, buf, sizeof(w));
+		writew(le16_to_cpu(w), base + offset);
+		break;
+	case 4:
+		memcpy(&l, buf, sizeof(l));
+		writel(le32_to_cpu(l), base + offset);
+		break;
+	case 8:
+		memcpy(&l, buf, sizeof(l));
+		writel(le32_to_cpu(l), base + offset);
+		memcpy(&l, buf + sizeof(l), sizeof(l));
+		writel(le32_to_cpu(l), base + offset + sizeof(l));
+		break;
+	default:
+		WARN_ON(true);
+	}
+
+	return 0;
+}
+
+static int virtio_mmio_generation(struct virtio_device *vdev, u32 *counter)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+
+	if (priv->version == 1)
+		*counter = 0;
+	else
+		*counter = readl(priv->base + VIRTIO_MMIO_CONFIG_GENERATION);
+
+	return 0;
+}
+
+static int virtio_mmio_get_status(struct virtio_device *vdev)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+
+	return readl(priv->base + VIRTIO_MMIO_STATUS) & 0xff;
+}
+
+static int virtio_mmio_set_status(struct virtio_device *vdev, u8 status)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+
+	/* We should never be setting status to 0 */
+	WARN_ON(status == 0);
+
+	writel(status, priv->base + VIRTIO_MMIO_STATUS);
+
+	return 0;
+}
+
+static int virtio_mmio_reset(struct virtio_device *vdev)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+
+	/* 0 status means a reset */
+	writel(0, priv->base + VIRTIO_MMIO_STATUS);
+
+	return 0;
+}
+
+static u64 virtio_mmio_get_features(struct virtio_device *vdev)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+	u64 features;
+
+	writel(1, priv->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
+	features = readl(priv->base + VIRTIO_MMIO_DEVICE_FEATURES);
+	features <<= 32;
+
+	writel(0, priv->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
+	features |= readl(priv->base + VIRTIO_MMIO_DEVICE_FEATURES);
+
+	return features;
+}
+
+ static int virtio_mmio_finalize_features(struct virtio_device *vdev)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+
+	/* Make sure there is are no mixed devices */
+	if (priv->version == 2 && !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
+		dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
+		return -EINVAL;
+	}
+
+	writel(1, priv->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
+	writel((u32)(vdev->features >> 32),
+	       priv->base + VIRTIO_MMIO_DRIVER_FEATURES);
+
+	writel(0, priv->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
+	writel((u32)vdev->features,
+	       priv->base + VIRTIO_MMIO_DRIVER_FEATURES);
+
+	return 0;
+}
+
+static struct virtqueue *virtio_mmio_setup_vq(struct virtio_device *vdev,
+					      unsigned int index)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+	struct virtqueue *vq;
+	unsigned int num;
+	int err;
+
+	/* Select the queue we're interested in */
+	writel(index, priv->base + VIRTIO_MMIO_QUEUE_SEL);
+
+	/* Queue shouldn't already be set up */
+	if (readl(priv->base + (priv->version == 1 ?
+	    VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
+		err = -ENOENT;
+		goto error_available;
+	}
+
+	num = readl(priv->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
+	if (num == 0) {
+		err = -ENOENT;
+		goto error_new_virtqueue;
+	}
+
+	/* Create the vring */
+	vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev);
+	if (!vq) {
+		err = -ENOMEM;
+		goto error_new_virtqueue;
+	}
+
+	/* Activate the queue */
+	writel(virtqueue_get_vring_size(vq),
+	       priv->base + VIRTIO_MMIO_QUEUE_NUM);
+	if (priv->version == 1) {
+		u64 q_pfn = virtqueue_get_desc_addr(vq) >> PAGE_SHIFT;
+
+		/*
+		 * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something
+		 * that doesn't fit in 32bit, fail the setup rather than
+		 * pretending to be successful.
+		 */
+		if (q_pfn >> 32) {
+			debug("platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n",
+			      0x1ULL << (32 + PAGE_SHIFT - 30));
+			err = -E2BIG;
+			goto error_bad_pfn;
+		}
+
+		writel(PAGE_SIZE, priv->base + VIRTIO_MMIO_QUEUE_ALIGN);
+		writel(q_pfn, priv->base + VIRTIO_MMIO_QUEUE_PFN);
+	} else {
+		u64 addr;
+
+		addr = virtqueue_get_desc_addr(vq);
+		writel((u32)addr, priv->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
+		writel((u32)(addr >> 32),
+		       priv->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
+
+		addr = virtqueue_get_avail_addr(vq);
+		writel((u32)addr, priv->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
+		writel((u32)(addr >> 32),
+		       priv->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
+
+		addr = virtqueue_get_used_addr(vq);
+		writel((u32)addr, priv->base + VIRTIO_MMIO_QUEUE_USED_LOW);
+		writel((u32)(addr >> 32),
+		       priv->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
+
+		writel(1, priv->base + VIRTIO_MMIO_QUEUE_READY);
+	}
+
+	return vq;
+
+error_bad_pfn:
+	vring_del_virtqueue(vq);
+
+error_new_virtqueue:
+	if (priv->version == 1) {
+		writel(0, priv->base + VIRTIO_MMIO_QUEUE_PFN);
+	} else {
+		writel(0, priv->base + VIRTIO_MMIO_QUEUE_READY);
+		WARN_ON(readl(priv->base + VIRTIO_MMIO_QUEUE_READY));
+	}
+
+error_available:
+	return ERR_PTR(err);
+}
+
+static void virtio_mmio_del_vq(struct virtqueue *vq)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vq->vdev);
+	unsigned int index = vq->index;
+
+	/* Select and deactivate the queue */
+	writel(index, priv->base + VIRTIO_MMIO_QUEUE_SEL);
+	if (priv->version == 1) {
+		writel(0, priv->base + VIRTIO_MMIO_QUEUE_PFN);
+	} else {
+		writel(0, priv->base + VIRTIO_MMIO_QUEUE_READY);
+		WARN_ON(readl(priv->base + VIRTIO_MMIO_QUEUE_READY));
+	}
+
+	vring_del_virtqueue(vq);
+}
+
+static int virtio_mmio_del_vqs(struct virtio_device *vdev)
+{
+	struct virtqueue *vq, *n;
+
+	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
+		virtio_mmio_del_vq(vq);
+
+	return 0;
+}
+
+static int virtio_mmio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
+				struct virtqueue *vqs[])
+{
+	int i;
+
+	for (i = 0; i < nvqs; ++i) {
+		vqs[i] = virtio_mmio_setup_vq(vdev, i);
+		if (IS_ERR(vqs[i])) {
+			virtio_mmio_del_vqs(vdev);
+			return PTR_ERR(vqs[i]);
+		}
+	}
+
+	return 0;
+}
+
+static int virtio_mmio_notify(struct virtio_device *vdev, struct virtqueue *vq)
+{
+	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
+
+	/*
+	 * We write the queue's selector into the notification register
+	 * to signal the other end
+	 */
+	writel(vq->index, priv->base + VIRTIO_MMIO_QUEUE_NOTIFY);
+
+	return 0;
+}
+
+static const struct virtio_config_ops virtio_mmio_config_ops = {
+	.get_config	= virtio_mmio_get_config,
+	.set_config	= virtio_mmio_set_config,
+	.generation	= virtio_mmio_generation,
+	.get_status	= virtio_mmio_get_status,
+	.set_status	= virtio_mmio_set_status,
+	.reset		= virtio_mmio_reset,
+	.get_features	= virtio_mmio_get_features,
+	.finalize_features	= virtio_mmio_finalize_features,
+	.find_vqs	= virtio_mmio_find_vqs,
+	.del_vqs	= virtio_mmio_del_vqs,
+	.notify		= virtio_mmio_notify,
+};
+
+
+/* Platform device */
+
+static int virtio_mmio_probe(struct device_d *dev)
+{
+	struct virtio_mmio_device *vm_dev;
+	struct resource *res;
+	unsigned long magic;
+
+	vm_dev = kzalloc(sizeof(*vm_dev), GFP_KERNEL);
+	if (!vm_dev)
+		return -ENOMEM;
+
+	vm_dev->vdev.dev.parent = dev;
+	vm_dev->vdev.config = &virtio_mmio_config_ops;
+
+	res = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(res))
+		return PTR_ERR(res);
+
+	vm_dev->base = IOMEM(res->start);
+
+	/* Check magic value */
+	magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
+	if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
+		dev_warn(dev, "Wrong magic value 0x%08lx!\n", magic);
+		return -ENODEV;
+	}
+
+	/* Check device version */
+	vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
+	if (vm_dev->version < 1 || vm_dev->version > 2) {
+		dev_err(dev, "Version %ld not supported!\n",
+				vm_dev->version);
+		return -ENXIO;
+	}
+
+	vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
+	if (vm_dev->vdev.id.device == 0) {
+		/*
+		 * virtio-mmio device with an ID 0 is a (dummy) placeholder
+		 * with no function. End probing now with no error reported.
+		 */
+		return -ENODEV;
+	}
+	vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
+
+	if (vm_dev->version == 1)
+		writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
+
+	dev->priv = vm_dev;
+
+	return register_virtio_device(&vm_dev->vdev);
+}
+
+static void virtio_mmio_remove(struct device_d *dev)
+{
+	struct virtio_mmio_device *vm_dev = dev->priv;
+	unregister_virtio_device(&vm_dev->vdev);
+}
+
+
+/* Platform driver */
+
+static const struct of_device_id virtio_mmio_match[] = {
+	{ .compatible = "virtio,mmio", },
+	{},
+};
+
+static struct driver_d virtio_mmio_driver = {
+	.probe		= virtio_mmio_probe,
+	.remove		= virtio_mmio_remove,
+	.name		= "virtio-mmio",
+	.of_compatible	= virtio_mmio_match,
+};
+
+static int __init virtio_mmio_init(void)
+{
+	return platform_driver_register(&virtio_mmio_driver);
+}
+
+module_init(virtio_mmio_init);
+
+MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
+MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
+MODULE_LICENSE("GPL");
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
new file mode 100644
index 0000000000..cac3362e72
--- /dev/null
+++ b/drivers/virtio/virtio_ring.c
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * virtio ring implementation
+ */
+
+#define pr_fmt(fmt) "virtio_ring: " fmt
+
+#include <common.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_types.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ring.h>
+#include <linux/bug.h>
+#include <dma.h>
+
+#define vq_debug(vq, fmt, ...) \
+	dev_dbg(&vq->vdev->dev, fmt, ##__VA_ARGS__)
+
+#define vq_info(vq, fmt, ...) \
+	dev_info(&vq->vdev->dev, fmt, ##__VA_ARGS__)
+
+int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
+		  unsigned int out_sgs, unsigned int in_sgs)
+{
+	struct vring_desc *desc;
+	unsigned int total_sg = out_sgs + in_sgs;
+	unsigned int i, n, avail, descs_used, uninitialized_var(prev);
+	int head;
+
+	WARN_ON(total_sg == 0);
+
+	head = vq->free_head;
+
+	desc = vq->vring.desc;
+	i = head;
+	descs_used = total_sg;
+
+	if (vq->num_free < descs_used) {
+		vq_debug(vq, "Can't add buf len %i - avail = %i\n",
+		      descs_used, vq->num_free);
+		/*
+		 * FIXME: for historical reasons, we force a notify here if
+		 * there are outgoing parts to the buffer.  Presumably the
+		 * host should service the ring ASAP.
+		 */
+		if (out_sgs)
+			virtio_notify(vq->vdev, vq);
+		return -ENOSPC;
+	}
+
+	for (n = 0; n < out_sgs; n++) {
+		struct virtio_sg *sg = sgs[n];
+
+		desc[i].flags = cpu_to_virtio16(vq->vdev, VRING_DESC_F_NEXT);
+		desc[i].addr = cpu_to_virtio64(vq->vdev, (u64)(size_t)sg->addr);
+		desc[i].len = cpu_to_virtio32(vq->vdev, sg->length);
+
+		prev = i;
+		i = virtio16_to_cpu(vq->vdev, desc[i].next);
+	}
+	for (; n < (out_sgs + in_sgs); n++) {
+		struct virtio_sg *sg = sgs[n];
+
+		desc[i].flags = cpu_to_virtio16(vq->vdev, VRING_DESC_F_NEXT |
+						VRING_DESC_F_WRITE);
+		desc[i].addr = cpu_to_virtio64(vq->vdev,
+					       (u64)(uintptr_t)sg->addr);
+		desc[i].len = cpu_to_virtio32(vq->vdev, sg->length);
+
+		prev = i;
+		i = virtio16_to_cpu(vq->vdev, desc[i].next);
+	}
+	/* Last one doesn't continue */
+	desc[prev].flags &= cpu_to_virtio16(vq->vdev, ~VRING_DESC_F_NEXT);
+
+	/* We're using some buffers from the free list. */
+	vq->num_free -= descs_used;
+
+	/* Update free pointer */
+	vq->free_head = i;
+
+	/*
+	 * Put entry in available array (but don't update avail->idx
+	 * until they do sync).
+	 */
+	avail = vq->avail_idx_shadow & (vq->vring.num - 1);
+	vq->vring.avail->ring[avail] = cpu_to_virtio16(vq->vdev, head);
+
+	/*
+	 * Descriptors and available array need to be set before we expose the
+	 * new available array entries.
+	 */
+	virtio_wmb();
+	vq->avail_idx_shadow++;
+	vq->vring.avail->idx = cpu_to_virtio16(vq->vdev, vq->avail_idx_shadow);
+	vq->num_added++;
+
+	/*
+	 * This is very unlikely, but theoretically possible.
+	 * Kick just in case.
+	 */
+	if (unlikely(vq->num_added == (1 << 16) - 1))
+		virtqueue_kick(vq);
+
+	return 0;
+}
+
+static bool virtqueue_kick_prepare(struct virtqueue *vq)
+{
+	u16 new, old;
+	bool needs_kick;
+
+	/*
+	 * We need to expose available array entries before checking
+	 * avail event.
+	 */
+	virtio_mb();
+
+	old = vq->avail_idx_shadow - vq->num_added;
+	new = vq->avail_idx_shadow;
+	vq->num_added = 0;
+
+	if (vq->event) {
+		needs_kick = vring_need_event(virtio16_to_cpu(vq->vdev,
+				vring_avail_event(&vq->vring)), new, old);
+	} else {
+		needs_kick = !(vq->vring.used->flags & cpu_to_virtio16(vq->vdev,
+				VRING_USED_F_NO_NOTIFY));
+	}
+
+	return needs_kick;
+}
+
+void virtqueue_kick(struct virtqueue *vq)
+{
+	if (virtqueue_kick_prepare(vq))
+		virtio_notify(vq->vdev, vq);
+}
+
+static void detach_buf(struct virtqueue *vq, unsigned int head)
+{
+	unsigned int i;
+	__virtio16 nextflag = cpu_to_virtio16(vq->vdev, VRING_DESC_F_NEXT);
+
+	/* Put back on free list: unmap first-level descriptors and find end */
+	i = head;
+
+	while (vq->vring.desc[i].flags & nextflag) {
+		i = virtio16_to_cpu(vq->vdev, vq->vring.desc[i].next);
+		vq->num_free++;
+	}
+
+	vq->vring.desc[i].next = cpu_to_virtio16(vq->vdev, vq->free_head);
+	vq->free_head = head;
+
+	/* Plus final descriptor */
+	vq->num_free++;
+}
+
+static inline bool more_used(const struct virtqueue *vq)
+{
+	return virtqueue_poll(vq, vq->last_used_idx);
+}
+
+void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len)
+{
+	unsigned int i;
+	u16 last_used;
+
+	if (!more_used(vq)) {
+		vq_debug(vq, "No more buffers in queue\n");
+		return NULL;
+	}
+
+	/* Only get used array entries after they have been exposed by host */
+	virtio_rmb();
+
+	last_used = (vq->last_used_idx & (vq->vring.num - 1));
+	i = virtio32_to_cpu(vq->vdev, vq->vring.used->ring[last_used].id);
+	if (len) {
+		*len = virtio32_to_cpu(vq->vdev,
+				       vq->vring.used->ring[last_used].len);
+		vq_debug(vq, "last used idx %u with len %u\n", i, *len);
+	}
+
+	if (unlikely(i >= vq->vring.num)) {
+		vq_info(vq, "id %u out of range\n", i);
+		return NULL;
+	}
+
+	detach_buf(vq, i);
+	vq->last_used_idx++;
+	/*
+	 * If we expect an interrupt for the next entry, tell host
+	 * by writing event index and flush out the write before
+	 * the read in the next get_buf call.
+	 */
+	if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT))
+		virtio_store_mb(&vring_used_event(&vq->vring),
+				cpu_to_virtio16(vq->vdev, vq->last_used_idx));
+
+	return (void *)(uintptr_t)virtio64_to_cpu(vq->vdev,
+						  vq->vring.desc[i].addr);
+}
+
+static struct virtqueue *__vring_new_virtqueue(unsigned int index,
+					       struct vring vring,
+					       struct virtio_device *vdev)
+{
+	unsigned int i;
+	struct virtqueue *vq;
+
+	vq = malloc(sizeof(*vq));
+	if (!vq)
+		return NULL;
+
+	vq->vdev = vdev;
+	vq->index = index;
+	vq->num_free = vring.num;
+	vq->vring = vring;
+	vq->last_used_idx = 0;
+	vq->avail_flags_shadow = 0;
+	vq->avail_idx_shadow = 0;
+	vq->num_added = 0;
+	list_add_tail(&vq->list, &vdev->vqs);
+
+	vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
+
+	/* Tell other side not to bother us */
+	vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+	if (!vq->event)
+		vq->vring.avail->flags = cpu_to_virtio16(vdev,
+				vq->avail_flags_shadow);
+
+	/* Put everything in free lists */
+	vq->free_head = 0;
+	for (i = 0; i < vring.num - 1; i++)
+		vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
+
+	return vq;
+}
+
+struct virtqueue *vring_create_virtqueue(unsigned int index, unsigned int num,
+					 unsigned int vring_align,
+					 struct virtio_device *vdev)
+{
+	struct virtqueue *vq;
+	void *queue = NULL;
+	struct vring vring;
+
+	/* We assume num is a power of 2 */
+	if (num & (num - 1)) {
+		pr_err("Bad virtqueue length %u\n", num);
+		return NULL;
+	}
+
+	/* TODO: allocate each queue chunk individually */
+	for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
+		queue = memalign(PAGE_SIZE, vring_size(num, vring_align));
+		if (queue)
+			break;
+	}
+
+	if (!num)
+		return NULL;
+
+	if (!queue) {
+		/* Try to get a single page. You are my only hope! */
+		queue = memalign(PAGE_SIZE, vring_size(num, vring_align));
+	}
+	if (!queue)
+		return NULL;
+
+	memset(queue, 0, vring_size(num, vring_align));
+	vring_init(&vring, num, queue, vring_align);
+
+	vq = __vring_new_virtqueue(index, vring, vdev);
+	if (!vq) {
+		free(queue);
+		return NULL;
+	}
+	vq_debug(vq, "created vring @ %p for vq with num %u\n", queue, num);
+
+	return vq;
+}
+
+void vring_del_virtqueue(struct virtqueue *vq)
+{
+	free(vq->vring.desc);
+	list_del(&vq->list);
+	free(vq);
+}
+
+unsigned int virtqueue_get_vring_size(struct virtqueue *vq)
+{
+	return vq->vring.num;
+}
+
+dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq)
+{
+	return (dma_addr_t)vq->vring.desc;
+}
+
+dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq)
+{
+	return (dma_addr_t)vq->vring.desc +
+	       ((char *)vq->vring.avail - (char *)vq->vring.desc);
+}
+
+dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq)
+{
+	return (dma_addr_t)vq->vring.desc +
+	       ((char *)vq->vring.used - (char *)vq->vring.desc);
+}
+
+bool virtqueue_poll(const struct virtqueue *vq, u16 last_used_idx)
+{
+	virtio_mb();
+
+	return last_used_idx != virtio16_to_cpu(vq->vdev, vq->vring.used->idx);
+}
+
+void virtqueue_dump(struct virtqueue *vq)
+{
+	unsigned int i;
+
+	printf("virtqueue %p for dev %s:\n", vq, vq->vdev->dev.name);
+	printf("\tindex %u, phys addr %p num %u\n",
+	       vq->index, vq->vring.desc, vq->vring.num);
+	printf("\tfree_head %u, num_added %u, num_free %u\n",
+	       vq->free_head, vq->num_added, vq->num_free);
+	printf("\tlast_used_idx %u, avail_flags_shadow %u, avail_idx_shadow %u\n",
+	       vq->last_used_idx, vq->avail_flags_shadow, vq->avail_idx_shadow);
+
+	printf("Descriptor dump:\n");
+	for (i = 0; i < vq->vring.num; i++) {
+		printf("\tdesc[%u] = { 0x%llx, len %u, flags %u, next %u }\n",
+		       i, vq->vring.desc[i].addr, vq->vring.desc[i].len,
+		       vq->vring.desc[i].flags, vq->vring.desc[i].next);
+	}
+
+	printf("Avail ring dump:\n");
+	printf("\tflags %u, idx %u\n",
+	       vq->vring.avail->flags, vq->vring.avail->idx);
+	for (i = 0; i < vq->vring.num; i++) {
+		printf("\tavail[%u] = %u\n",
+		       i, vq->vring.avail->ring[i]);
+	}
+
+	printf("Used ring dump:\n");
+	printf("\tflags %u, idx %u\n",
+	       vq->vring.used->flags, vq->vring.used->idx);
+	for (i = 0; i < vq->vring.num; i++) {
+		printf("\tused[%u] = { %u, %u }\n", i,
+		       vq->vring.used->ring[i].id, vq->vring.used->ring[i].len);
+	}
+}
+
+int virtio_notify(struct virtio_device *vdev, struct virtqueue *vq)
+{
+	return vdev->config->notify(vdev, vq);
+}
diff --git a/include/linux/typecheck.h b/include/linux/typecheck.h
new file mode 100644
index 0000000000..20d310331e
--- /dev/null
+++ b/include/linux/typecheck.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef TYPECHECK_H_INCLUDED
+#define TYPECHECK_H_INCLUDED
+
+/*
+ * Check at compile time that something is of a particular type.
+ * Always evaluates to 1 so you may use it easily in comparisons.
+ */
+#define typecheck(type,x) \
+({	type __dummy; \
+	typeof(x) __dummy2; \
+	(void)(&__dummy == &__dummy2); \
+	1; \
+})
+
+/*
+ * Check at compile time that 'function' is a certain type, or is a pointer
+ * to that type (needs to use typedef for the function type.)
+ */
+#define typecheck_fn(type,function) \
+({	typeof(type) __tmp = function; \
+	(void)__tmp; \
+})
+
+#endif		/* TYPECHECK_H_INCLUDED */
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
new file mode 100644
index 0000000000..8a1a80ddc8
--- /dev/null
+++ b/include/linux/virtio.h
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VIRTIO_H
+#define _LINUX_VIRTIO_H
+/* Everything a virtio driver needs to work with any particular virtio
+ * implementation. */
+#include <linux/types.h>
+#include <driver.h>
+#include <linux/slab.h>
+
+struct virtio_device_id {
+	__u32 device;
+	__u32 vendor;
+};
+#define VIRTIO_DEV_ANY_ID	0xffffffff
+
+/**
+ * virtio scatter-gather struct
+ *
+ * @addr:		sg buffer address
+ * @lengh:		sg buffer length
+ */
+struct virtio_sg {
+	void *addr;
+	size_t length;
+};
+
+struct virtio_config_ops;
+
+/**
+ * virtio_device - representation of a device using virtio
+ * @index: unique position on the virtio bus
+ * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
+ * @config_enabled: configuration change reporting enabled
+ * @config_change_pending: configuration change reported while disabled
+ * @dev: underlying device.
+ * @id: the device type identification (used to match it with a driver).
+ * @config: the configuration ops for this device.
+ * @vringh_config: configuration ops for host vrings.
+ * @vqs: the list of virtqueues for this device.
+ * @features: the features supported by both driver and device.
+ * @priv: private pointer for the driver's use.
+ */
+struct virtio_device {
+	int index;
+	bool failed;
+	bool config_enabled;
+	bool config_change_pending;
+	struct device_d dev;
+	struct virtio_device_id id;
+	const struct virtio_config_ops *config;
+	struct list_head vqs;
+	u64 features;
+	void *priv;
+	u32 status_param;
+};
+
+static inline struct virtio_device *dev_to_virtio(struct device_d *_dev)
+{
+	return container_of(_dev, struct virtio_device, dev);
+}
+
+void virtio_add_status(struct virtio_device *dev, unsigned int status);
+int register_virtio_device(struct virtio_device *dev);
+void unregister_virtio_device(struct virtio_device *dev);
+bool is_virtio_device(struct device_d *dev);
+
+void virtio_break_device(struct virtio_device *dev);
+
+void virtio_config_changed(struct virtio_device *dev);
+void virtio_config_disable(struct virtio_device *dev);
+void virtio_config_enable(struct virtio_device *dev);
+int virtio_finalize_features(struct virtio_device *dev);
+
+size_t virtio_max_dma_size(struct virtio_device *vdev);
+
+#define virtio_device_for_each_vq(vdev, vq) \
+	list_for_each_entry(vq, &vdev->vqs, list)
+
+/**
+ * virtio_driver - operations for a virtio I/O driver
+ * @driver: underlying device driver (populate name and owner).
+ * @id_table: the ids serviced by this driver.
+ * @feature_table: an array of feature numbers supported by this driver.
+ * @feature_table_size: number of entries in the feature table array.
+ * @feature_table_legacy: same as feature_table but when working in legacy mode.
+ * @feature_table_size_legacy: number of entries in feature table legacy array.
+ * @probe: the function to call when a device is found.  Returns 0 or -errno.
+ * @scan: optional function to call after successful probe; intended
+ *    for virtio-scsi to invoke a scan.
+ * @remove: the function to call when a device is removed.
+ * @config_changed: optional function to call when the device configuration
+ *    changes; may be called in interrupt context.
+ * @freeze: optional function to call during suspend/hibernation.
+ * @restore: optional function to call on resume.
+ */
+struct virtio_driver {
+	struct driver_d driver;
+	const struct virtio_device_id *id_table;
+	const unsigned int *feature_table;
+	unsigned int feature_table_size;
+	const unsigned int *feature_table_legacy;
+	unsigned int feature_table_size_legacy;
+	int (*validate)(struct virtio_device *dev);
+	int (*probe)(struct virtio_device *dev);
+	void (*scan)(struct virtio_device *dev);
+	void (*remove)(struct virtio_device *dev);
+	void (*config_changed)(struct virtio_device *dev);
+};
+
+static inline struct virtio_driver *drv_to_virtio(struct driver_d *drv)
+{
+	return container_of(drv, struct virtio_driver, driver);
+}
+
+int virtio_driver_register(struct virtio_driver *drv);
+
+/* module_virtio_driver() - Helper macro for drivers that don't do
+ * anything special in module init/exit.  This eliminates a lot of
+ * boilerplate.  Each module may only use this macro once, and
+ * calling it replaces module_init() and module_exit()
+ */
+#define module_virtio_driver(drv) \
+	device_virtio_driver(drv)
+
+#define device_virtio_driver(drv) \
+	register_driver_macro(device,virtio,drv)
+
+#endif /* _LINUX_VIRTIO_H */
diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h
new file mode 100644
index 0000000000..825aaefac9
--- /dev/null
+++ b/include/linux/virtio_byteorder.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VIRTIO_BYTEORDER_H
+#define _LINUX_VIRTIO_BYTEORDER_H
+#include <linux/types.h>
+#include <uapi/linux/virtio_types.h>
+
+static inline bool virtio_legacy_is_little_endian(void)
+{
+#ifdef __LITTLE_ENDIAN
+	return true;
+#else
+	return false;
+#endif
+}
+
+static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val)
+{
+	if (little_endian)
+		return le16_to_cpu((__force __le16)val);
+	else
+		return be16_to_cpu((__force __be16)val);
+}
+
+static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val)
+{
+	if (little_endian)
+		return (__force __virtio16)cpu_to_le16(val);
+	else
+		return (__force __virtio16)cpu_to_be16(val);
+}
+
+static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val)
+{
+	if (little_endian)
+		return le32_to_cpu((__force __le32)val);
+	else
+		return be32_to_cpu((__force __be32)val);
+}
+
+static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val)
+{
+	if (little_endian)
+		return (__force __virtio32)cpu_to_le32(val);
+	else
+		return (__force __virtio32)cpu_to_be32(val);
+}
+
+static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val)
+{
+	if (little_endian)
+		return le64_to_cpu((__force __le64)val);
+	else
+		return be64_to_cpu((__force __be64)val);
+}
+
+static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val)
+{
+	if (little_endian)
+		return (__force __virtio64)cpu_to_le64(val);
+	else
+		return (__force __virtio64)cpu_to_be64(val);
+}
+
+#endif /* _LINUX_VIRTIO_BYTEORDER */
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
new file mode 100644
index 0000000000..5ee0807fb0
--- /dev/null
+++ b/include/linux/virtio_config.h
@@ -0,0 +1,480 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VIRTIO_CONFIG_H
+#define _LINUX_VIRTIO_CONFIG_H
+
+#include <linux/err.h>
+#include <linux/bug.h>
+#include <linux/virtio.h>
+#include <linux/virtio_byteorder.h>
+#include <linux/compiler_types.h>
+#include <linux/typecheck.h>
+#include <uapi/linux/virtio_config.h>
+
+#ifndef might_sleep
+#define might_sleep() do { } while (0)
+#endif
+
+struct virtio_shm_region {
+	u64 addr;
+	u64 len;
+};
+
+struct virtqueue;
+
+/* virtio bus operations */
+struct virtio_config_ops {
+	/**
+	 * get_config() - read the value of a configuration field
+	 *
+	 * @vdev:	the real virtio device
+	 * @offset:	the offset of the configuration field
+	 * @buf:	the buffer to write the field value into
+	 * @len:	the length of the buffer
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_config)(struct virtio_device *vdev, unsigned int offset,
+			  void *buf, unsigned int len);
+	/**
+	 * set_config() - write the value of a configuration field
+	 *
+	 * @vdev:	the real virtio device
+	 * @offset:	the offset of the configuration field
+	 * @buf:	the buffer to read the field value from
+	 * @len:	the length of the buffer
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*set_config)(struct virtio_device *vdev, unsigned int offset,
+			  const void *buf, unsigned int len);
+	/**
+	 * generation() - config generation counter
+	 *
+	 * @vdev:	the real virtio device
+	 * @counter:	the returned config generation counter
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*generation)(struct virtio_device *vdev, u32 *counter);
+	/**
+	 * get_status() - read the status byte
+	 *
+	 * @vdev:	the real virtio device
+	 * @status:	the returned status byte
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_status)(struct virtio_device *vdev);
+	/**
+	 * set_status() - write the status byte
+	 *
+	 * @vdev:	the real virtio device
+	 * @status:	the new status byte
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*set_status)(struct virtio_device *vdev, u8 status);
+	/**
+	 * reset() - reset the device
+	 *
+	 * @vdev:	the real virtio device
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*reset)(struct virtio_device *vdev);
+	/**
+	 * get_features() - get the array of feature bits for this device
+	 *
+	 * @vdev:	the real virtio device
+	 * @return features
+	 */
+	u64 (*get_features)(struct virtio_device *vdev);
+	/**
+	 * set_features() - confirm what device features we'll be using
+	 *
+	 * @vdev:	the real virtio device
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*set_features)(struct virtio_device *vdev);
+	/**
+	 * find_vqs() - find virtqueues and instantiate them
+	 *
+	 * @vdev:	the real virtio device
+	 * @nvqs:	the number of virtqueues to find
+	 * @vqs:	on success, includes new virtqueues
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*find_vqs)(struct virtio_device *vdev, unsigned int nvqs,
+			struct virtqueue *vqs[]);
+	/**
+	 * del_vqs() - free virtqueues found by find_vqs()
+	 *
+	 * @vdev:	the real virtio device
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*del_vqs)(struct virtio_device *vdev);
+	/**
+	 * notify() - notify the device to process the queue
+	 *
+	 * @vdev:	the real virtio device
+	 * @vq:		virtqueue to process
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*notify)(struct virtio_device *vdev, struct virtqueue *vq);
+	/**
+	 * finalize_features() - confirm what device features we'll be using.
+	 * @vdev: 	the virtio_device
+	 * 		This gives the final feature bits for the device: it can change
+	 * 		the dev->feature bits if it wants.
+	 * @returns 0 if OK, -ve on error
+	 */
+	int (*finalize_features)(struct virtio_device *vdev);
+};
+
+/* If driver didn't advertise the feature, it will never appear. */
+void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
+					 unsigned int fbit);
+
+/**
+ * __virtio_test_bit - helper to test feature bits. For use by transports.
+ *                     Devices should normally use virtio_has_feature,
+ *                     which includes more checks.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline bool __virtio_test_bit(const struct virtio_device *vdev,
+				     unsigned int fbit)
+{
+	/* Did you forget to fix assumptions on max features? */
+	if (__builtin_constant_p(fbit))
+		BUILD_BUG_ON(fbit >= 64);
+	else
+		BUG_ON(fbit >= 64);
+
+	return vdev->features & BIT_ULL(fbit);
+}
+
+/**
+ * __virtio_set_bit - helper to set feature bits. For use by transports.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline void __virtio_set_bit(struct virtio_device *vdev,
+				    unsigned int fbit)
+{
+	/* Did you forget to fix assumptions on max features? */
+	if (__builtin_constant_p(fbit))
+		BUILD_BUG_ON(fbit >= 64);
+	else
+		BUG_ON(fbit >= 64);
+
+	vdev->features |= BIT_ULL(fbit);
+}
+
+/**
+ * __virtio_clear_bit - helper to clear feature bits. For use by transports.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline void __virtio_clear_bit(struct virtio_device *vdev,
+				      unsigned int fbit)
+{
+	/* Did you forget to fix assumptions on max features? */
+	if (__builtin_constant_p(fbit))
+		BUILD_BUG_ON(fbit >= 64);
+	else
+		BUG_ON(fbit >= 64);
+
+	vdev->features &= ~BIT_ULL(fbit);
+}
+
+/**
+ * virtio_has_feature - helper to determine if this device has this feature.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline bool virtio_has_feature(const struct virtio_device *vdev,
+				      unsigned int fbit)
+{
+	if (fbit < VIRTIO_TRANSPORT_F_START)
+		virtio_check_driver_offered_feature(vdev, fbit);
+
+	return __virtio_test_bit(vdev, fbit);
+}
+
+/**
+ * virtio_has_dma_quirk - determine whether this device has the DMA quirk
+ * @vdev: the device
+ */
+static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev)
+{
+	/*
+	 * Note the reverse polarity of the quirk feature (compared to most
+	 * other features), this is for compatibility with legacy systems.
+	 */
+	return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM);
+}
+
+static inline bool virtio_is_little_endian(struct virtio_device *vdev)
+{
+	return virtio_legacy_is_little_endian();
+}
+
+
+/**
+ * virtio_get_config() - read the value of a configuration field
+ *
+ * @vdev:	the real virtio device
+ * @offset:	the offset of the configuration field
+ * @buf:	the buffer to write the field value into
+ * @len:	the length of the buffer
+ * @return 0 if OK, -ve on error
+ */
+static inline int virtio_get_config(struct virtio_device *vdev, unsigned int offset,
+				    void *buf, unsigned int len)
+{
+	return vdev->config->get_config(vdev, offset, buf, len);
+}
+
+/**
+ * virtio_set_config() - write the value of a configuration field
+ *
+ * @vdev:	the real virtio device
+ * @offset:	the offset of the configuration field
+ * @buf:	the buffer to read the field value from
+ * @len:	the length of the buffer
+ * @return 0 if OK, -ve on error
+ */
+int virtio_set_config(struct virtio_device *vdev, unsigned int offset,
+		      void *buf, unsigned int len);
+
+/**
+ * virtio_find_vqs() - find virtqueues and instantiate them
+ *
+ * @vdev:	the real virtio device
+ * @nvqs:	the number of virtqueues to find
+ * @vqs:	on success, includes new virtqueues
+ * @return 0 if OK, -ve on error
+ */
+int virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
+		    struct virtqueue *vqs[]);
+
+/**
+ * virtio_device_ready - enable vq use in probe function
+ * @vdev: the device
+ *
+ * Driver must call this to use vqs in the probe function.
+ *
+ * Note: vqs are enabled automatically after probe returns.
+ */
+static inline
+void virtio_device_ready(struct virtio_device *dev)
+{
+	unsigned status = dev->config->get_status(dev);
+
+	BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
+	dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
+}
+
+
+/* Memory accessors */
+static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
+{
+	return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
+{
+	return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
+}
+
+static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
+{
+	return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
+{
+	return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
+}
+
+static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
+{
+	return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
+{
+	return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
+}
+
+/* Read @count fields, @bytes each */
+static inline void __virtio_cread_many(struct virtio_device *vdev,
+				       unsigned int offset,
+				       void *buf, size_t count, size_t bytes)
+{
+	u32 old, gen;
+	int i;
+
+	/* no need to check return value as generation can be optional */
+	vdev->config->generation(vdev, &gen);
+	do {
+		old = gen;
+
+		for (i = 0; i < count; i++)
+			virtio_get_config(vdev, offset + bytes * i,
+					  buf + i * bytes, bytes);
+
+		vdev->config->generation(vdev, &gen);
+	} while (gen != old);
+}
+
+static inline void virtio_cread_bytes(struct virtio_device *vdev,
+				      unsigned int offset,
+				      void *buf, size_t len)
+{
+	__virtio_cread_many(vdev, offset, buf, len, 1);
+}
+
+static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
+{
+	u8 ret;
+
+	virtio_get_config(vdev, offset, &ret, sizeof(ret));
+	return ret;
+}
+
+static inline void virtio_cwrite8(struct virtio_device *vdev,
+				  unsigned int offset, u8 val)
+{
+	virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+static inline u16 virtio_cread16(struct virtio_device *vdev,
+				 unsigned int offset)
+{
+	u16 ret;
+
+	virtio_get_config(vdev, offset, &ret, sizeof(ret));
+	return virtio16_to_cpu(vdev, (__force __virtio16)ret);
+}
+
+static inline void virtio_cwrite16(struct virtio_device *vdev,
+				   unsigned int offset, u16 val)
+{
+	val = (__force u16)cpu_to_virtio16(vdev, val);
+	virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+static inline u32 virtio_cread32(struct virtio_device *vdev,
+				 unsigned int offset)
+{
+	u32 ret;
+
+	virtio_get_config(vdev, offset, &ret, sizeof(ret));
+	return virtio32_to_cpu(vdev, (__force __virtio32)ret);
+}
+
+static inline void virtio_cwrite32(struct virtio_device *vdev,
+				   unsigned int offset, u32 val)
+{
+	val = (__force u32)cpu_to_virtio32(vdev, val);
+	virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+static inline u64 virtio_cread64(struct virtio_device *vdev,
+				 unsigned int offset)
+{
+	u64 ret;
+
+	__virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
+	return virtio64_to_cpu(vdev, (__force __virtio64)ret);
+}
+
+static inline void virtio_cwrite64(struct virtio_device *vdev,
+				   unsigned int offset, u64 val)
+{
+	val = (__force u64)cpu_to_virtio64(vdev, val);
+	virtio_set_config(vdev, offset, &val, sizeof(val));
+}
+
+/* Config space read accessor */
+#define virtio_cread(vdev, structname, member, ptr)			\
+	do {								\
+		/* Must match the member's type, and be integer */	\
+		if (!typecheck(typeof((((structname *)0)->member)), *(ptr))) \
+			(*ptr) = 1;					\
+									\
+		switch (sizeof(*ptr)) {					\
+		case 1:							\
+			*(ptr) = virtio_cread8(vdev,			\
+					       offsetof(structname, member)); \
+			break;						\
+		case 2:							\
+			*(ptr) = virtio_cread16(vdev,			\
+						offsetof(structname, member)); \
+			break;						\
+		case 4:							\
+			*(ptr) = virtio_cread32(vdev,			\
+						offsetof(structname, member)); \
+			break;						\
+		case 8:							\
+			*(ptr) = virtio_cread64(vdev,			\
+						offsetof(structname, member)); \
+			break;						\
+		default:						\
+			WARN_ON(true);					\
+		}							\
+	} while (0)
+
+/* Config space write accessor */
+#define virtio_cwrite(vdev, structname, member, ptr)			\
+	do {								\
+		/* Must match the member's type, and be integer */	\
+		if (!typecheck(typeof((((structname *)0)->member)), *(ptr))) \
+			WARN_ON((*ptr) == 1);				\
+									\
+		switch (sizeof(*ptr)) {					\
+		case 1:							\
+			virtio_cwrite8(vdev,				\
+				       offsetof(structname, member),	\
+				       *(ptr));				\
+			break;						\
+		case 2:							\
+			virtio_cwrite16(vdev,				\
+					offsetof(structname, member),	\
+					*(ptr));			\
+			break;						\
+		case 4:							\
+			virtio_cwrite32(vdev,				\
+					offsetof(structname, member),	\
+					*(ptr));			\
+			break;						\
+		case 8:							\
+			virtio_cwrite64(vdev,				\
+					offsetof(structname, member),	\
+					*(ptr));			\
+			break;						\
+		default:						\
+			WARN_ON(true);					\
+		}							\
+	} while (0)
+
+/* Conditional config space accessors */
+#define virtio_cread_feature(vdev, fbit, structname, member, ptr)	\
+	({								\
+		int _r = 0;						\
+		if (!virtio_has_feature(vdev, fbit))			\
+			_r = -ENOENT;					\
+		else							\
+			virtio_cread(vdev, structname, member, ptr);	\
+		_r;							\
+	})
+
+#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+int arch_has_restricted_virtio_memory_access(void);
+#else
+static inline int arch_has_restricted_virtio_memory_access(void)
+{
+	return 0;
+}
+#endif /* CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS */
+
+
+#undef might_sleep
+
+#endif /* _LINUX_VIRTIO_CONFIG_H */
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
new file mode 100644
index 0000000000..3c11592b09
--- /dev/null
+++ b/include/linux/virtio_ring.h
@@ -0,0 +1,330 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * From Linux kernel include/uapi/linux/virtio_ring.h
+ */
+
+#ifndef _LINUX_VIRTIO_RING_H
+#define _LINUX_VIRTIO_RING_H
+
+#include <linux/virtio_types.h>
+
+/* This marks a buffer as continuing via the next field */
+#define VRING_DESC_F_NEXT		1
+/* This marks a buffer as write-only (otherwise read-only) */
+#define VRING_DESC_F_WRITE		2
+/* This means the buffer contains a list of buffer descriptors */
+#define VRING_DESC_F_INDIRECT		4
+
+/*
+ * The Host uses this in used->flags to advise the Guest: don't kick me when
+ * you add a buffer. It's unreliable, so it's simply an optimization. Guest
+ * will still kick if it's out of buffers.
+ */
+#define VRING_USED_F_NO_NOTIFY		1
+
+/*
+ * The Guest uses this in avail->flags to advise the Host: don't interrupt me
+ * when you consume a buffer. It's unreliable, so it's simply an optimization.
+ */
+#define VRING_AVAIL_F_NO_INTERRUPT	1
+
+/* We support indirect buffer descriptors */
+#define VIRTIO_RING_F_INDIRECT_DESC	28
+
+/*
+ * The Guest publishes the used index for which it expects an interrupt
+ * at the end of the avail ring. Host should ignore the avail->flags field.
+ *
+ * The Host publishes the avail index for which it expects a kick
+ * at the end of the used ring. Guest should ignore the used->flags field.
+ */
+#define VIRTIO_RING_F_EVENT_IDX		29
+
+/* Virtio ring descriptors: 16 bytes. These can chain together via "next". */
+struct vring_desc {
+	/* Address (guest-physical) */
+	__virtio64 addr;
+	/* Length */
+	__virtio32 len;
+	/* The flags as indicated above */
+	__virtio16 flags;
+	/* We chain unused descriptors via this, too */
+	__virtio16 next;
+};
+
+struct vring_avail {
+	__virtio16 flags;
+	__virtio16 idx;
+	__virtio16 ring[];
+};
+
+struct vring_used_elem {
+	/* Index of start of used descriptor chain */
+	__virtio32 id;
+	/* Total length of the descriptor chain which was used (written to) */
+	__virtio32 len;
+};
+
+struct vring_used {
+	__virtio16 flags;
+	__virtio16 idx;
+	struct vring_used_elem ring[];
+};
+
+struct vring {
+	unsigned int num;
+	struct vring_desc *desc;
+	struct vring_avail *avail;
+	struct vring_used *used;
+};
+
+/**
+ * virtqueue - a queue to register buffers for sending or receiving.
+ *
+ * @list: the chain of virtqueues for this device
+ * @vdev: the virtio device this queue was created for
+ * @index: the zero-based ordinal number for this queue
+ * @num_free: number of elements we expect to be able to fit
+ * @vring: actual memory layout for this queue
+ * @event: host publishes avail event idx
+ * @free_head: head of free buffer list
+ * @num_added: number we've added since last sync
+ * @last_used_idx: last used index we've seen
+ * @avail_flags_shadow: last written value to avail->flags
+ * @avail_idx_shadow: last written value to avail->idx in guest byte order
+ */
+struct virtqueue {
+	struct list_head list;
+	struct virtio_device *vdev;
+	unsigned int index;
+	unsigned int num_free;
+	struct vring vring;
+	bool event;
+	unsigned int free_head;
+	unsigned int num_added;
+	u16 last_used_idx;
+	u16 avail_flags_shadow;
+	u16 avail_idx_shadow;
+};
+
+/*
+ * Alignment requirements for vring elements.
+ * When using pre-virtio 1.0 layout, these fall out naturally.
+ */
+#define VRING_AVAIL_ALIGN_SIZE		2
+#define VRING_USED_ALIGN_SIZE		4
+#define VRING_DESC_ALIGN_SIZE		16
+
+/*
+ * We publish the used event index at the end of the available ring,
+ * and vice versa. They are at the end for backwards compatibility.
+ */
+#define vring_used_event(vr)	((vr)->avail->ring[(vr)->num])
+#define vring_avail_event(vr)	(*(__virtio16 *)&(vr)->used->ring[(vr)->num])
+
+static inline void vring_init(struct vring *vr, unsigned int num, void *p,
+			      unsigned long align)
+{
+	vr->num = num;
+	vr->desc = p;
+	vr->avail = p + num * sizeof(struct vring_desc);
+	vr->used = (void *)(((uintptr_t)&vr->avail->ring[num] +
+		   sizeof(__virtio16) + align - 1) & ~(align - 1));
+}
+
+static inline unsigned int vring_size(unsigned int num, unsigned long align)
+{
+	return ((sizeof(struct vring_desc) * num +
+		sizeof(__virtio16) * (3 + num)  + align - 1) & ~(align - 1)) +
+		sizeof(__virtio16) * 3 + sizeof(struct vring_used_elem) * num;
+}
+
+/*
+ * The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX.
+ * Assuming a given event_idx value from the other side, if we have just
+ * incremented index from old to new_idx, should we trigger an event?
+ */
+static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
+{
+	/*
+	 * Note: Xen has similar logic for notification hold-off
+	 * in include/xen/interface/io/ring.h with req_event and req_prod
+	 * corresponding to event_idx + 1 and new_idx respectively.
+	 * Note also that req_event and req_prod in Xen start at 1,
+	 * event indexes in virtio start at 0.
+	 */
+	return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
+}
+
+struct virtio_sg;
+
+/**
+ * virtqueue_add - expose buffers to other end
+ *
+ * @vq:		the struct virtqueue we're talking about
+ * @sgs:	array of terminated scatterlists
+ * @out_sgs:	the number of scatterlists readable by other side
+ * @in_sgs:	the number of scatterlists which are writable
+ *		(after readable ones)
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
+		  unsigned int out_sgs, unsigned int in_sgs);
+
+/**
+ * virtqueue_kick - update after add_buf
+ *
+ * @vq:		the struct virtqueue
+ *
+ * After one or more virtqueue_add() calls, invoke this to kick
+ * the other side.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ */
+void virtqueue_kick(struct virtqueue *vq);
+
+/**
+ * virtqueue_get_buf - get the next used buffer
+ *
+ * @vq:		the struct virtqueue we're talking about
+ * @len:	the length written into the buffer
+ *
+ * If the device wrote data into the buffer, @len will be set to the
+ * amount written. This means you don't need to clear the buffer
+ * beforehand to ensure there's no data leakage in the case of short
+ * writes.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * Returns NULL if there are no used buffers, or the memory buffer
+ * handed to virtqueue_add_*().
+ */
+void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
+
+/**
+ * vring_create_virtqueue - create a virtqueue for a virtio device
+ *
+ * @index:	the index of the queue
+ * @num:	number of elements of the queue
+ * @vring_align:the alignment requirement of the descriptor ring
+ * @udev:	the virtio transport device
+ * @return: the virtqueue pointer or NULL if failed
+ *
+ * This creates a virtqueue and allocates the descriptor ring for a virtio
+ * device. The caller should query virtqueue_get_ring_size() to learn the
+ * actual size of the ring.
+ *
+ * This API is supposed to be called by the virtio transport driver in the
+ * virtio find_vqs() uclass method.
+ */
+struct virtqueue *vring_create_virtqueue(unsigned int index, unsigned int num,
+					 unsigned int vring_align,
+					 struct virtio_device *vdev);
+
+/**
+ * vring_del_virtqueue - destroy a virtqueue
+ *
+ * @vq:		the struct virtqueue we're talking about
+ *
+ * This destroys a virtqueue. If created with vring_create_virtqueue(),
+ * this also frees the descriptor ring.
+ *
+ * This API is supposed to be called by the virtio transport driver in the
+ * virtio del_vqs() uclass method.
+ */
+void vring_del_virtqueue(struct virtqueue *vq);
+
+/**
+ * virtqueue_get_vring_size - get the size of the virtqueue's vring
+ *
+ * @vq:		the struct virtqueue containing the vring of interest
+ * @return: the size of the vring in a virtqueue.
+ */
+unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
+
+/**
+ * virtqueue_get_desc_addr - get the vring descriptor table address
+ *
+ * @vq:		the struct virtqueue containing the vring of interest
+ * @return: the descriptor table address of the vring in a virtqueue.
+ */
+dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
+
+/**
+ * virtqueue_get_avail_addr - get the vring available ring address
+ *
+ * @vq:		the struct virtqueue containing the vring of interest
+ * @return: the available ring address of the vring in a virtqueue.
+ */
+dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
+
+/**
+ * virtqueue_get_used_addr - get the vring used ring address
+ *
+ * @vq:		the struct virtqueue containing the vring of interest
+ * @return: the used ring address of the vring in a virtqueue.
+ */
+dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
+
+/**
+ * virtqueue_poll - query pending used buffers
+ *
+ * @vq:			the struct virtqueue we're talking about
+ * @last_used_idx:	virtqueue last used index
+ *
+ * Returns "true" if there are pending used buffers in the queue.
+ */
+bool virtqueue_poll(const struct virtqueue *vq, u16 last_used_idx);
+
+/**
+ * virtio_notify() - notify the device to process the queue
+ *
+ * @vdev:	the real virtio device
+ * @vq:		virtqueue to process
+ * @return 0 if OK, -ve on error
+ */
+int virtio_notify(struct virtio_device *vdev, struct virtqueue *vq);
+
+
+/**
+ * virtqueue_dump - dump the virtqueue for debugging
+ *
+ * @vq:		the struct virtqueue we're talking about
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ */
+void virtqueue_dump(struct virtqueue *vq);
+
+/*
+ * Barriers in virtio are tricky. Since we are not in a hyperviosr/guest
+ * scenario, having these as nops is enough to work as expected.
+ */
+
+static inline void virtio_mb(void)
+{
+}
+
+static inline void virtio_rmb(void)
+{
+}
+
+static inline void virtio_wmb(void)
+{
+}
+
+static inline void virtio_store_mb(__virtio16 *p, __virtio16 v)
+{
+	WRITE_ONCE(*p, v);
+}
+
+#endif /* _LINUX_VIRTIO_RING_H */
diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
new file mode 100644
index 0000000000..d888f013d9
--- /dev/null
+++ b/include/uapi/linux/virtio_blk.h
@@ -0,0 +1,203 @@
+#ifndef _LINUX_VIRTIO_BLK_H
+#define _LINUX_VIRTIO_BLK_H
+/* This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE. */
+#include <linux/types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_types.h>
+
+/* Feature bits */
+#define VIRTIO_BLK_F_SIZE_MAX	1	/* Indicates maximum segment size */
+#define VIRTIO_BLK_F_SEG_MAX	2	/* Indicates maximum # of segments */
+#define VIRTIO_BLK_F_GEOMETRY	4	/* Legacy geometry available  */
+#define VIRTIO_BLK_F_RO		5	/* Disk is read-only */
+#define VIRTIO_BLK_F_BLK_SIZE	6	/* Block size of disk is available*/
+#define VIRTIO_BLK_F_TOPOLOGY	10	/* Topology information is available */
+#define VIRTIO_BLK_F_MQ		12	/* support more than one vq */
+#define VIRTIO_BLK_F_DISCARD	13	/* DISCARD is supported */
+#define VIRTIO_BLK_F_WRITE_ZEROES	14	/* WRITE ZEROES is supported */
+
+/* Legacy feature bits */
+#ifndef VIRTIO_BLK_NO_LEGACY
+#define VIRTIO_BLK_F_BARRIER	0	/* Does host support barriers? */
+#define VIRTIO_BLK_F_SCSI	7	/* Supports scsi command passthru */
+#define VIRTIO_BLK_F_FLUSH	9	/* Flush command supported */
+#define VIRTIO_BLK_F_CONFIG_WCE	11	/* Writeback mode available in config */
+#ifndef __KERNEL__
+/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
+#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
+#endif
+#endif /* !VIRTIO_BLK_NO_LEGACY */
+
+#define VIRTIO_BLK_ID_BYTES	20	/* ID string length */
+
+struct virtio_blk_config {
+	/* The capacity (in 512-byte sectors). */
+	__virtio64 capacity;
+	/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
+	__virtio32 size_max;
+	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
+	__virtio32 seg_max;
+	/* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
+	struct virtio_blk_geometry {
+		__virtio16 cylinders;
+		__u8 heads;
+		__u8 sectors;
+	} geometry;
+
+	/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
+	__virtio32 blk_size;
+
+	/* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
+	/* exponent for physical block per logical block. */
+	__u8 physical_block_exp;
+	/* alignment offset in logical blocks. */
+	__u8 alignment_offset;
+	/* minimum I/O size without performance penalty in logical blocks. */
+	__virtio16 min_io_size;
+	/* optimal sustained I/O size in logical blocks. */
+	__virtio32 opt_io_size;
+
+	/* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
+	__u8 wce;
+	__u8 unused;
+
+	/* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
+	__virtio16 num_queues;
+
+	/* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
+	/*
+	 * The maximum discard sectors (in 512-byte sectors) for
+	 * one segment.
+	 */
+	__virtio32 max_discard_sectors;
+	/*
+	 * The maximum number of discard segments in a
+	 * discard command.
+	 */
+	__virtio32 max_discard_seg;
+	/* Discard commands must be aligned to this number of sectors. */
+	__virtio32 discard_sector_alignment;
+
+	/* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */
+	/*
+	 * The maximum number of write zeroes sectors (in 512-byte sectors) in
+	 * one segment.
+	 */
+	__virtio32 max_write_zeroes_sectors;
+	/*
+	 * The maximum number of segments in a write zeroes
+	 * command.
+	 */
+	__virtio32 max_write_zeroes_seg;
+	/*
+	 * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the
+	 * deallocation of one or more of the sectors.
+	 */
+	__u8 write_zeroes_may_unmap;
+
+	__u8 unused1[3];
+} __attribute__((packed));
+
+/*
+ * Command types
+ *
+ * Usage is a bit tricky as some bits are used as flags and some are not.
+ *
+ * Rules:
+ *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
+ *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
+ *   and may not be combined with any of the other flags.
+ */
+
+/* These two define direction. */
+#define VIRTIO_BLK_T_IN		0
+#define VIRTIO_BLK_T_OUT	1
+
+#ifndef VIRTIO_BLK_NO_LEGACY
+/* This bit says it's a scsi command, not an actual read or write. */
+#define VIRTIO_BLK_T_SCSI_CMD	2
+#endif /* VIRTIO_BLK_NO_LEGACY */
+
+/* Cache flush command */
+#define VIRTIO_BLK_T_FLUSH	4
+
+/* Get device ID command */
+#define VIRTIO_BLK_T_GET_ID    8
+
+/* Discard command */
+#define VIRTIO_BLK_T_DISCARD	11
+
+/* Write zeroes command */
+#define VIRTIO_BLK_T_WRITE_ZEROES	13
+
+#ifndef VIRTIO_BLK_NO_LEGACY
+/* Barrier before this op. */
+#define VIRTIO_BLK_T_BARRIER	0x80000000
+#endif /* !VIRTIO_BLK_NO_LEGACY */
+
+/*
+ * This comes first in the read scatter-gather list.
+ * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
+ * this is the first element of the read scatter-gather list.
+ */
+struct virtio_blk_outhdr {
+	/* VIRTIO_BLK_T* */
+	__virtio32 type;
+	/* io priority. */
+	__virtio32 ioprio;
+	/* Sector (ie. 512 byte offset) */
+	__virtio64 sector;
+};
+
+/* Unmap this range (only valid for write zeroes command) */
+#define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP	0x00000001
+
+/* Discard/write zeroes range for each request. */
+struct virtio_blk_discard_write_zeroes {
+	/* discard/write zeroes start sector */
+	__le64 sector;
+	/* number of discard/write zeroes sectors */
+	__le32 num_sectors;
+	/* flags for this range */
+	__le32 flags;
+};
+
+#ifndef VIRTIO_BLK_NO_LEGACY
+struct virtio_scsi_inhdr {
+	__virtio32 errors;
+	__virtio32 data_len;
+	__virtio32 sense_len;
+	__virtio32 residual;
+};
+#endif /* !VIRTIO_BLK_NO_LEGACY */
+
+/* And this is the final byte of the write scatter-gather list. */
+#define VIRTIO_BLK_S_OK		0
+#define VIRTIO_BLK_S_IOERR	1
+#define VIRTIO_BLK_S_UNSUPP	2
+#endif /* _LINUX_VIRTIO_BLK_H */
diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
new file mode 100644
index 0000000000..b5eda06f0d
--- /dev/null
+++ b/include/uapi/linux/virtio_config.h
@@ -0,0 +1,95 @@
+#ifndef _UAPI_LINUX_VIRTIO_CONFIG_H
+#define _UAPI_LINUX_VIRTIO_CONFIG_H
+/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE. */
+
+/* Virtio devices use a standardized configuration space to define their
+ * features and pass configuration information, but each implementation can
+ * store and access that space differently. */
+#include <linux/types.h>
+
+/* Status byte for guest to report progress, and synchronize features. */
+/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
+#define VIRTIO_CONFIG_S_ACKNOWLEDGE	1
+/* We have found a driver for the device. */
+#define VIRTIO_CONFIG_S_DRIVER		2
+/* Driver has used its parts of the config, and is happy */
+#define VIRTIO_CONFIG_S_DRIVER_OK	4
+/* Driver has finished configuring features */
+#define VIRTIO_CONFIG_S_FEATURES_OK	8
+/* Device entered invalid state, driver must reset it */
+#define VIRTIO_CONFIG_S_NEEDS_RESET	0x40
+/* We've given up on this device. */
+#define VIRTIO_CONFIG_S_FAILED		0x80
+
+/*
+ * Virtio feature bits VIRTIO_TRANSPORT_F_START through
+ * VIRTIO_TRANSPORT_F_END are reserved for the transport
+ * being used (e.g. virtio_ring, virtio_pci etc.), the
+ * rest are per-device feature bits.
+ */
+#define VIRTIO_TRANSPORT_F_START	28
+#define VIRTIO_TRANSPORT_F_END		38
+
+#ifndef VIRTIO_CONFIG_NO_LEGACY
+/* Do we get callbacks when the ring is completely used, even if we've
+ * suppressed them? */
+#define VIRTIO_F_NOTIFY_ON_EMPTY	24
+
+/* Can the device handle any descriptor layout? */
+#define VIRTIO_F_ANY_LAYOUT		27
+#endif /* VIRTIO_CONFIG_NO_LEGACY */
+
+/* v1.0 compliant. */
+#define VIRTIO_F_VERSION_1		32
+
+/*
+ * If clear - device has the platform DMA (e.g. IOMMU) bypass quirk feature.
+ * If set - use platform DMA tools to access the memory.
+ *
+ * Note the reverse polarity (compared to most other features),
+ * this is for compatibility with legacy systems.
+ */
+#define VIRTIO_F_ACCESS_PLATFORM	33
+#ifndef __KERNEL__
+/* Legacy name for VIRTIO_F_ACCESS_PLATFORM (for compatibility with old userspace) */
+#define VIRTIO_F_IOMMU_PLATFORM		VIRTIO_F_ACCESS_PLATFORM
+#endif /* __KERNEL__ */
+
+/* This feature indicates support for the packed virtqueue layout. */
+#define VIRTIO_F_RING_PACKED		34
+
+/*
+ * This feature indicates that memory accesses by the driver and the
+ * device are ordered in a way described by the platform.
+ */
+#define VIRTIO_F_ORDER_PLATFORM		36
+
+/*
+ * Does the device support Single Root I/O Virtualization?
+ */
+#define VIRTIO_F_SR_IOV			37
+#endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */
diff --git a/include/uapi/linux/virtio_console.h b/include/uapi/linux/virtio_console.h
new file mode 100644
index 0000000000..7e6ec2ff05
--- /dev/null
+++ b/include/uapi/linux/virtio_console.h
@@ -0,0 +1,78 @@
+/*
+ * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers:
+ *
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Copyright (C) Red Hat, Inc., 2009, 2010, 2011
+ * Copyright (C) Amit Shah <amit.shah@redhat.com>, 2009, 2010, 2011
+ */
+#ifndef _UAPI_LINUX_VIRTIO_CONSOLE_H
+#define _UAPI_LINUX_VIRTIO_CONSOLE_H
+#include <linux/types.h>
+#include <linux/virtio_types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+
+/* Feature bits */
+#define VIRTIO_CONSOLE_F_SIZE	0	/* Does host provide console size? */
+#define VIRTIO_CONSOLE_F_MULTIPORT 1	/* Does host provide multiple ports? */
+#define VIRTIO_CONSOLE_F_EMERG_WRITE 2 /* Does host support emergency write? */
+
+#define VIRTIO_CONSOLE_BAD_ID		(~(__u32)0)
+
+struct virtio_console_config {
+	/* colums of the screens */
+	__virtio16 cols;
+	/* rows of the screens */
+	__virtio16 rows;
+	/* max. number of ports this device can hold */
+	__virtio32 max_nr_ports;
+	/* emergency write register */
+	__virtio32 emerg_wr;
+} __attribute__((packed));
+
+/*
+ * A message that's passed between the Host and the Guest for a
+ * particular port.
+ */
+struct virtio_console_control {
+	__virtio32 id;		/* Port number */
+	__virtio16 event;	/* The kind of control event (see below) */
+	__virtio16 value;	/* Extra information for the key */
+};
+
+/* Some events for control messages */
+#define VIRTIO_CONSOLE_DEVICE_READY	0
+#define VIRTIO_CONSOLE_PORT_ADD		1
+#define VIRTIO_CONSOLE_PORT_REMOVE	2
+#define VIRTIO_CONSOLE_PORT_READY	3
+#define VIRTIO_CONSOLE_CONSOLE_PORT	4
+#define VIRTIO_CONSOLE_RESIZE		5
+#define VIRTIO_CONSOLE_PORT_OPEN	6
+#define VIRTIO_CONSOLE_PORT_NAME	7
+
+
+#endif /* _UAPI_LINUX_VIRTIO_CONSOLE_H */
diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
new file mode 100644
index 0000000000..bc1c0621f5
--- /dev/null
+++ b/include/uapi/linux/virtio_ids.h
@@ -0,0 +1,58 @@
+#ifndef _LINUX_VIRTIO_IDS_H
+#define _LINUX_VIRTIO_IDS_H
+/*
+ * Virtio IDs
+ *
+ * This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE. */
+
+#define VIRTIO_ID_NET			1 /* virtio net */
+#define VIRTIO_ID_BLOCK			2 /* virtio block */
+#define VIRTIO_ID_CONSOLE		3 /* virtio console */
+#define VIRTIO_ID_RNG			4 /* virtio rng */
+#define VIRTIO_ID_BALLOON		5 /* virtio balloon */
+#define VIRTIO_ID_IOMEM			6 /* virtio ioMemory */
+#define VIRTIO_ID_RPMSG			7 /* virtio remote processor messaging */
+#define VIRTIO_ID_SCSI			8 /* virtio scsi */
+#define VIRTIO_ID_9P			9 /* 9p virtio console */
+#define VIRTIO_ID_MAC80211_WLAN		10 /* virtio WLAN MAC */
+#define VIRTIO_ID_RPROC_SERIAL		11 /* virtio remoteproc serial link */
+#define VIRTIO_ID_CAIF			12 /* Virtio caif */
+#define VIRTIO_ID_MEMORY_BALLOON	13 /* virtio memory balloon */
+#define VIRTIO_ID_GPU			16 /* virtio GPU */
+#define VIRTIO_ID_CLOCK			17 /* virtio clock/timer */
+#define VIRTIO_ID_INPUT			18 /* virtio input */
+#define VIRTIO_ID_VSOCK			19 /* virtio vsock transport */
+#define VIRTIO_ID_CRYPTO		20 /* virtio crypto */
+#define VIRTIO_ID_SIGNAL_DIST		21 /* virtio signal distribution device */
+#define VIRTIO_ID_PSTORE		22 /* virtio pstore device */
+#define VIRTIO_ID_IOMMU			23 /* virtio IOMMU */
+#define VIRTIO_ID_MEM			24 /* virtio mem */
+#define VIRTIO_ID_FS			26 /* virtio filesystem */
+#define VIRTIO_ID_PMEM			27 /* virtio pmem */
+#define VIRTIO_ID_MAC80211_HWSIM	29 /* virtio mac80211-hwsim */
+
+#endif /* _LINUX_VIRTIO_IDS_H */
diff --git a/include/uapi/linux/virtio_mmio.h b/include/uapi/linux/virtio_mmio.h
new file mode 100644
index 0000000000..0650f91bea
--- /dev/null
+++ b/include/uapi/linux/virtio_mmio.h
@@ -0,0 +1,152 @@
+/*
+ * Virtio platform device driver
+ *
+ * Copyright 2011, ARM Ltd.
+ *
+ * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
+ *
+ * This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _LINUX_VIRTIO_MMIO_H
+#define _LINUX_VIRTIO_MMIO_H
+
+/*
+ * Control registers
+ */
+
+/* Magic value ("virt" string) - Read Only */
+#define VIRTIO_MMIO_MAGIC_VALUE		0x000
+
+/* Virtio device version - Read Only */
+#define VIRTIO_MMIO_VERSION		0x004
+
+/* Virtio device ID - Read Only */
+#define VIRTIO_MMIO_DEVICE_ID		0x008
+
+/* Virtio vendor ID - Read Only */
+#define VIRTIO_MMIO_VENDOR_ID		0x00c
+
+/* Bitmask of the features supported by the device (host)
+ * (32 bits per set) - Read Only */
+#define VIRTIO_MMIO_DEVICE_FEATURES	0x010
+
+/* Device (host) features set selector - Write Only */
+#define VIRTIO_MMIO_DEVICE_FEATURES_SEL	0x014
+
+/* Bitmask of features activated by the driver (guest)
+ * (32 bits per set) - Write Only */
+#define VIRTIO_MMIO_DRIVER_FEATURES	0x020
+
+/* Activated features set selector - Write Only */
+#define VIRTIO_MMIO_DRIVER_FEATURES_SEL	0x024
+
+
+#ifndef VIRTIO_MMIO_NO_LEGACY /* LEGACY DEVICES ONLY! */
+
+/* Guest's memory page size in bytes - Write Only */
+#define VIRTIO_MMIO_GUEST_PAGE_SIZE	0x028
+
+#endif
+
+
+/* Queue selector - Write Only */
+#define VIRTIO_MMIO_QUEUE_SEL		0x030
+
+/* Maximum size of the currently selected queue - Read Only */
+#define VIRTIO_MMIO_QUEUE_NUM_MAX	0x034
+
+/* Queue size for the currently selected queue - Write Only */
+#define VIRTIO_MMIO_QUEUE_NUM		0x038
+
+
+#ifndef VIRTIO_MMIO_NO_LEGACY /* LEGACY DEVICES ONLY! */
+
+/* Used Ring alignment for the currently selected queue - Write Only */
+#define VIRTIO_MMIO_QUEUE_ALIGN		0x03c
+
+/* Guest's PFN for the currently selected queue - Read Write */
+#define VIRTIO_MMIO_QUEUE_PFN		0x040
+
+#endif
+
+
+/* Ready bit for the currently selected queue - Read Write */
+#define VIRTIO_MMIO_QUEUE_READY		0x044
+
+/* Queue notifier - Write Only */
+#define VIRTIO_MMIO_QUEUE_NOTIFY	0x050
+
+/* Interrupt status - Read Only */
+#define VIRTIO_MMIO_INTERRUPT_STATUS	0x060
+
+/* Interrupt acknowledge - Write Only */
+#define VIRTIO_MMIO_INTERRUPT_ACK	0x064
+
+/* Device status register - Read Write */
+#define VIRTIO_MMIO_STATUS		0x070
+
+/* Selected queue's Descriptor Table address, 64 bits in two halves */
+#define VIRTIO_MMIO_QUEUE_DESC_LOW	0x080
+#define VIRTIO_MMIO_QUEUE_DESC_HIGH	0x084
+
+/* Selected queue's Available Ring address, 64 bits in two halves */
+#define VIRTIO_MMIO_QUEUE_AVAIL_LOW	0x090
+#define VIRTIO_MMIO_QUEUE_AVAIL_HIGH	0x094
+
+/* Selected queue's Used Ring address, 64 bits in two halves */
+#define VIRTIO_MMIO_QUEUE_USED_LOW	0x0a0
+#define VIRTIO_MMIO_QUEUE_USED_HIGH	0x0a4
+
+/* Shared memory region id */
+#define VIRTIO_MMIO_SHM_SEL             0x0ac
+
+/* Shared memory region length, 64 bits in two halves */
+#define VIRTIO_MMIO_SHM_LEN_LOW         0x0b0
+#define VIRTIO_MMIO_SHM_LEN_HIGH        0x0b4
+
+/* Shared memory region base address, 64 bits in two halves */
+#define VIRTIO_MMIO_SHM_BASE_LOW        0x0b8
+#define VIRTIO_MMIO_SHM_BASE_HIGH       0x0bc
+
+/* Configuration atomicity value */
+#define VIRTIO_MMIO_CONFIG_GENERATION	0x0fc
+
+/* The config space is defined by each driver as
+ * the per-driver configuration space - Read Write */
+#define VIRTIO_MMIO_CONFIG		0x100
+
+
+
+/*
+ * Interrupt flags (re: interrupt status & acknowledge registers)
+ */
+
+#define VIRTIO_MMIO_INT_VRING		(1 << 0)
+#define VIRTIO_MMIO_INT_CONFIG		(1 << 1)
+
+#endif
diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
new file mode 100644
index 0000000000..b72a5b8b4a
--- /dev/null
+++ b/include/uapi/linux/virtio_ring.h
@@ -0,0 +1,244 @@
+#ifndef _UAPI_LINUX_VIRTIO_RING_H
+#define _UAPI_LINUX_VIRTIO_RING_H
+/* An interface for efficient virtio implementation, currently for use by KVM,
+ * but hopefully others soon.  Do NOT change this since it will
+ * break existing servers and clients.
+ *
+ * This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Copyright Rusty Russell IBM Corporation 2007. */
+#ifndef __KERNEL__
+#include <stdint.h>
+#endif
+#include <linux/types.h>
+#include <uapi/linux/virtio_types.h>
+
+/* This marks a buffer as continuing via the next field. */
+#define VRING_DESC_F_NEXT	1
+/* This marks a buffer as write-only (otherwise read-only). */
+#define VRING_DESC_F_WRITE	2
+/* This means the buffer contains a list of buffer descriptors. */
+#define VRING_DESC_F_INDIRECT	4
+
+/*
+ * Mark a descriptor as available or used in packed ring.
+ * Notice: they are defined as shifts instead of shifted values.
+ */
+#define VRING_PACKED_DESC_F_AVAIL	7
+#define VRING_PACKED_DESC_F_USED	15
+
+/* The Host uses this in used->flags to advise the Guest: don't kick me when
+ * you add a buffer.  It's unreliable, so it's simply an optimization.  Guest
+ * will still kick if it's out of buffers. */
+#define VRING_USED_F_NO_NOTIFY	1
+/* The Guest uses this in avail->flags to advise the Host: don't interrupt me
+ * when you consume a buffer.  It's unreliable, so it's simply an
+ * optimization.  */
+#define VRING_AVAIL_F_NO_INTERRUPT	1
+
+/* Enable events in packed ring. */
+#define VRING_PACKED_EVENT_FLAG_ENABLE	0x0
+/* Disable events in packed ring. */
+#define VRING_PACKED_EVENT_FLAG_DISABLE	0x1
+/*
+ * Enable events for a specific descriptor in packed ring.
+ * (as specified by Descriptor Ring Change Event Offset/Wrap Counter).
+ * Only valid if VIRTIO_RING_F_EVENT_IDX has been negotiated.
+ */
+#define VRING_PACKED_EVENT_FLAG_DESC	0x2
+
+/*
+ * Wrap counter bit shift in event suppression structure
+ * of packed ring.
+ */
+#define VRING_PACKED_EVENT_F_WRAP_CTR	15
+
+/* We support indirect buffer descriptors */
+#define VIRTIO_RING_F_INDIRECT_DESC	28
+
+/* The Guest publishes the used index for which it expects an interrupt
+ * at the end of the avail ring. Host should ignore the avail->flags field. */
+/* The Host publishes the avail index for which it expects a kick
+ * at the end of the used ring. Guest should ignore the used->flags field. */
+#define VIRTIO_RING_F_EVENT_IDX		29
+
+/* Alignment requirements for vring elements.
+ * When using pre-virtio 1.0 layout, these fall out naturally.
+ */
+#define VRING_AVAIL_ALIGN_SIZE 2
+#define VRING_USED_ALIGN_SIZE 4
+#define VRING_DESC_ALIGN_SIZE 16
+
+/* Virtio ring descriptors: 16 bytes.  These can chain together via "next". */
+struct vring_desc {
+	/* Address (guest-physical). */
+	__virtio64 addr;
+	/* Length. */
+	__virtio32 len;
+	/* The flags as indicated above. */
+	__virtio16 flags;
+	/* We chain unused descriptors via this, too */
+	__virtio16 next;
+};
+
+struct vring_avail {
+	__virtio16 flags;
+	__virtio16 idx;
+	__virtio16 ring[];
+};
+
+/* u32 is used here for ids for padding reasons. */
+struct vring_used_elem {
+	/* Index of start of used descriptor chain. */
+	__virtio32 id;
+	/* Total length of the descriptor chain which was used (written to) */
+	__virtio32 len;
+};
+
+typedef struct vring_used_elem __attribute__((aligned(VRING_USED_ALIGN_SIZE)))
+	vring_used_elem_t;
+
+struct vring_used {
+	__virtio16 flags;
+	__virtio16 idx;
+	vring_used_elem_t ring[];
+};
+
+/*
+ * The ring element addresses are passed between components with different
+ * alignments assumptions. Thus, we might need to decrease the compiler-selected
+ * alignment, and so must use a typedef to make sure the aligned attribute
+ * actually takes hold:
+ *
+ * https://gcc.gnu.org/onlinedocs//gcc/Common-Type-Attributes.html#Common-Type-Attributes
+ *
+ * When used on a struct, or struct member, the aligned attribute can only
+ * increase the alignment; in order to decrease it, the packed attribute must
+ * be specified as well. When used as part of a typedef, the aligned attribute
+ * can both increase and decrease alignment, and specifying the packed
+ * attribute generates a warning.
+ */
+typedef struct vring_desc __attribute__((aligned(VRING_DESC_ALIGN_SIZE)))
+	vring_desc_t;
+typedef struct vring_avail __attribute__((aligned(VRING_AVAIL_ALIGN_SIZE)))
+	vring_avail_t;
+typedef struct vring_used __attribute__((aligned(VRING_USED_ALIGN_SIZE)))
+	vring_used_t;
+
+struct vring {
+	unsigned int num;
+
+	vring_desc_t *desc;
+
+	vring_avail_t *avail;
+
+	vring_used_t *used;
+};
+
+#ifndef VIRTIO_RING_NO_LEGACY
+
+/* The standard layout for the ring is a continuous chunk of memory which looks
+ * like this.  We assume num is a power of 2.
+ *
+ * struct vring
+ * {
+ *	// The actual descriptors (16 bytes each)
+ *	struct vring_desc desc[num];
+ *
+ *	// A ring of available descriptor heads with free-running index.
+ *	__virtio16 avail_flags;
+ *	__virtio16 avail_idx;
+ *	__virtio16 available[num];
+ *	__virtio16 used_event_idx;
+ *
+ *	// Padding to the next align boundary.
+ *	char pad[];
+ *
+ *	// A ring of used descriptor heads with free-running index.
+ *	__virtio16 used_flags;
+ *	__virtio16 used_idx;
+ *	struct vring_used_elem used[num];
+ *	__virtio16 avail_event_idx;
+ * };
+ */
+/* We publish the used event index at the end of the available ring, and vice
+ * versa. They are at the end for backwards compatibility. */
+#define vring_used_event(vr) ((vr)->avail->ring[(vr)->num])
+#define vring_avail_event(vr) (*(__virtio16 *)&(vr)->used->ring[(vr)->num])
+
+static inline void vring_init(struct vring *vr, unsigned int num, void *p,
+			      unsigned long align)
+{
+	vr->num = num;
+	vr->desc = p;
+	vr->avail = (struct vring_avail *)((char *)p + num * sizeof(struct vring_desc));
+	vr->used = (void *)(((uintptr_t)&vr->avail->ring[num] + sizeof(__virtio16)
+		+ align-1) & ~(align - 1));
+}
+
+static inline unsigned vring_size(unsigned int num, unsigned long align)
+{
+	return ((sizeof(struct vring_desc) * num + sizeof(__virtio16) * (3 + num)
+		 + align - 1) & ~(align - 1))
+		+ sizeof(__virtio16) * 3 + sizeof(struct vring_used_elem) * num;
+}
+
+#endif /* VIRTIO_RING_NO_LEGACY */
+
+/* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */
+/* Assuming a given event_idx value from the other side, if
+ * we have just incremented index from old to new_idx,
+ * should we trigger an event? */
+static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
+{
+	/* Note: Xen has similar logic for notification hold-off
+	 * in include/xen/interface/io/ring.h with req_event and req_prod
+	 * corresponding to event_idx + 1 and new_idx respectively.
+	 * Note also that req_event and req_prod in Xen start at 1,
+	 * event indexes in virtio start at 0. */
+	return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
+}
+
+struct vring_packed_desc_event {
+	/* Descriptor Ring Change Event Offset/Wrap Counter. */
+	__le16 off_wrap;
+	/* Descriptor Ring Change Event Flags. */
+	__le16 flags;
+};
+
+struct vring_packed_desc {
+	/* Buffer Address. */
+	__le64 addr;
+	/* Buffer Length. */
+	__le32 len;
+	/* Buffer ID. */
+	__le16 id;
+	/* The flags depending on descriptor type. */
+	__le16 flags;
+};
+
+#endif /* _UAPI_LINUX_VIRTIO_RING_H */
diff --git a/include/uapi/linux/virtio_rng.h b/include/uapi/linux/virtio_rng.h
new file mode 100644
index 0000000000..c4d5de896f
--- /dev/null
+++ b/include/uapi/linux/virtio_rng.h
@@ -0,0 +1,8 @@
+#ifndef _LINUX_VIRTIO_RNG_H
+#define _LINUX_VIRTIO_RNG_H
+/* This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers. */
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+
+#endif /* _LINUX_VIRTIO_RNG_H */
diff --git a/include/uapi/linux/virtio_types.h b/include/uapi/linux/virtio_types.h
new file mode 100644
index 0000000000..55c3b73872
--- /dev/null
+++ b/include/uapi/linux/virtio_types.h
@@ -0,0 +1,46 @@
+#ifndef _UAPI_LINUX_VIRTIO_TYPES_H
+#define _UAPI_LINUX_VIRTIO_TYPES_H
+/* Type definitions for virtio implementations.
+ *
+ * This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * Copyright (C) 2014 Red Hat, Inc.
+ * Author: Michael S. Tsirkin <mst@redhat.com>
+ */
+#include <linux/types.h>
+
+/*
+ * __virtio{16,32,64} have the following meaning:
+ * - __u{16,32,64} for virtio devices in legacy mode, accessed in native endian
+ * - __le{16,32,64} for standard-compliant virtio devices
+ */
+
+typedef __u16 __bitwise __virtio16;
+typedef __u32 __bitwise __virtio32;
+typedef __u64 __bitwise __virtio64;
+
+#endif /* _UAPI_LINUX_VIRTIO_TYPES_H */