MIPS: KVM: Expose MSA registers

Add KVM register numbers for the MIPS SIMD Architecture (MSA) registers,
and implement access to them with the KVM_GET_ONE_REG / KVM_SET_ONE_REG
ioctls when the MSA capability is enabled (exposed in a later patch) and
present in the guest according to its Config3.MSAP bit.

The MSA vector registers use the same register numbers as the FPU
registers except with a different size (128bits). Since MSA depends on
Status.FR=1, these registers are inaccessible when Status.FR=0. These
registers are returned as a single native endian 128bit value, rather
than least significant half first with each 64-bit half native endian as
the kernel uses internally.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: linux-doc@vger.kernel.org

1 files changed, 11 insertions, 1 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index a1e9bfa5fe9ea..62809871814b3 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1981,8 +1981,11 @@ registers, find a list below:
   MIPS  | KVM_REG_MIPS_COUNT_HZ         | 64
   MIPS  | KVM_REG_MIPS_FPR_32(0..31)    | 32
   MIPS  | KVM_REG_MIPS_FPR_64(0..31)    | 64
+  MIPS  | KVM_REG_MIPS_VEC_128(0..31)   | 128
   MIPS  | KVM_REG_MIPS_FCR_IR           | 32
   MIPS  | KVM_REG_MIPS_FCR_CSR          | 32
+  MIPS  | KVM_REG_MIPS_MSA_IR           | 32
+  MIPS  | KVM_REG_MIPS_MSA_CSR          | 32
 
 ARM registers are mapped using the lower 32 bits.  The upper 16 of that
 is the register group type, or coprocessor number:
@@ -2040,14 +2043,21 @@ MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following
 id bit patterns depending on the size of the register being accessed. They are
 always accessed according to the current guest FPU mode (Status.FR and
 Config5.FRE), i.e. as the guest would see them, and they become unpredictable
-if the guest FPU mode is changed:
+if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector
+registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they
+overlap the FPU registers:
   0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers)
   0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers)
+  0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers)
 
 MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the
 following id bit patterns:
   0x7020 0000 0003 01 <0:3> <reg:5>
 
+MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the
+following id bit patterns:
+  0x7020 0000 0003 02 <0:3> <reg:5>
+
 
 4.69 KVM_GET_ONE_REG