kvm: nVMX: Introduce KVM_CAP_NESTED_STATE

For nested virtualization L0 KVM is managing a bit of state for L2 guests,
this state can not be captured through the currently available IOCTLs. In
fact the state captured through all of these IOCTLs is usually a mix of L1
and L2 state. It is also dependent on whether the L2 guest was running at
the moment when the process was interrupted to save its state.

With this capability, there are two new vcpu ioctls: KVM_GET_NESTED_STATE
and KVM_SET_NESTED_STATE. These can be used for saving and restoring a VM
that is in VMX operation.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Jim Mattson <jmattson@google.com>
[karahmed@ - rename structs and functions and make them ready for AMD and
             address previous comments.
           - handle nested.smm state.
           - rebase & a bit of refactoring.
           - Merge 7/8 and 8/8 into one patch. ]
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index c535c2fdea136..86299efa804ad 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -378,4 +378,41 @@ struct kvm_sync_regs {
 #define KVM_X86_QUIRK_LINT0_REENABLED	(1 << 0)
 #define KVM_X86_QUIRK_CD_NW_CLEARED	(1 << 1)
 
+#define KVM_STATE_NESTED_GUEST_MODE	0x00000001
+#define KVM_STATE_NESTED_RUN_PENDING	0x00000002
+
+#define KVM_STATE_NESTED_SMM_GUEST_MODE	0x00000001
+#define KVM_STATE_NESTED_SMM_VMXON	0x00000002
+
+struct kvm_vmx_nested_state {
+	__u64 vmxon_pa;
+	__u64 vmcs_pa;
+
+	struct {
+		__u16 flags;
+	} smm;
+};
+
+/* for KVM_CAP_NESTED_STATE */
+struct kvm_nested_state {
+	/* KVM_STATE_* flags */
+	__u16 flags;
+
+	/* 0 for VMX, 1 for SVM.  */
+	__u16 format;
+
+	/* 128 for SVM, 128 + VMCS size for VMX.  */
+	__u32 size;
+
+	union {
+		/* VMXON, VMCS */
+		struct kvm_vmx_nested_state vmx;
+
+		/* Pad the header to 128 bytes.  */
+		__u8 pad[120];
+	};
+
+	__u8 data[0];
+};
+
 #endif /* _ASM_X86_KVM_H */