diff mbox series

[5/6] x86: KVM: Enable AVX-NE-CONVERT CPUID and expose it to guest

Message ID 20221019084734.3590760-6-jiaxi.chen@linux.intel.com
State New
Headers
Series x86: KVM: Expose CPUID to guest for new Intel platform instructions |

Commit Message

Jiaxi Chen Oct. 19, 2022, 8:47 a.m. UTC 
  AVX-NE-CONVERT is a new set of instructions in the latest Intel platform
Sierra Forest, which can convert low precision floating point like
BF16/FP16 to high precision floating point FP32. It can also convert
FP32 elements to BF16. This instruction allows the platform to have
improved AI capabilities and better compatibility.

The bit definition:
CPUID.(EAX=7,ECX=1):EDX[bit 5]

This patch enables this CPUID in the kernel feature bits and expose it
to guest OS.

Signed-off-by: Jiaxi Chen <jiaxi.chen@linux.intel.com>
---
 arch/x86/include/asm/cpufeatures.h | 1 +
 arch/x86/kvm/cpuid.c               | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index b2aa761ea110..4e0bbffedbb4 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -425,6 +425,7 @@ 
 
 /* Intel-defined CPU features, CPUID level 0x00000007:1 (EDX), word 20 */
 #define X86_FEATURE_AVX_VNNI_INT8       (20*32+ 4) /* Support for VPDPB[SU,UU,SS]D[,S] */
+#define X86_FEATURE_AVX_NE_CONVERT      (20*32+ 5) /* AVX NE CONVERT Instructions */
 
 /*
  * BUG word(s)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b1b53a5c788a..fcd00c68e546 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -661,7 +661,8 @@  void kvm_set_cpu_caps(void)
 		F(AVX_IFMA));
 
 	kvm_cpu_cap_mask(CPUID_7_1_EDX,
-		F(AVX_VNNI_INT8));
+		F(AVX_VNNI_INT8) | F(AVX_NE_CONVERT)
+	);
 
 	kvm_cpu_cap_mask(CPUID_D_1_EAX,
 		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | f_xfd