Commit 99b66854 authored by Tao Su's avatar Tao Su Committed by Sean Christopherson
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KVM: x86: Advertise AMX-COMPLEX CPUID to userspace 



Latest Intel platform GraniteRapids-D introduces AMX-COMPLEX, which adds
two instructions to perform matrix multiplication of two tiles containing
complex elements and accumulate the results into a packed single precision
tile.

AMX-COMPLEX is enumerated via CPUID.(EAX=7,ECX=1):EDX[bit 8]

Advertise AMX_COMPLEX if it's supported in hardware.  There are no VMX
controls for the feature, i.e. the instructions can't be interecepted, and
KVM advertises base AMX in CPUID if AMX is supported in hardware, even if
KVM doesn't advertise AMX as being supported in XCR0, e.g. because the
process didn't opt-in to allocating tile data.

Signed-off-by: default avatarTao Su <tao1.su@linux.intel.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230802022954.193843-1-tao1.su@linux.intel.com


[sean: tweak last paragraph of changelog]
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent a788fbb7

arch/x86/kvm/cpuid.c

+2 −1
Original line number Diff line number Diff line
@@ -647,7 +647,8 @@ void kvm_set_cpu_caps(void) 
	);



	kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,

		F(AVX_VNNI_INT8) | F(AVX_NE_CONVERT) | F(PREFETCHITI)

		F(AVX_VNNI_INT8) | F(AVX_NE_CONVERT) | F(PREFETCHITI) |

		F(AMX_COMPLEX)

	);



	kvm_cpu_cap_mask(CPUID_D_1_EAX,

arch/x86/kvm/reverse_cpuid.h

+1 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ enum kvm_only_cpuid_leafs { 
/* Intel-defined sub-features, CPUID level 0x00000007:1 (EDX) */

#define X86_FEATURE_AVX_VNNI_INT8       KVM_X86_FEATURE(CPUID_7_1_EDX, 4)

#define X86_FEATURE_AVX_NE_CONVERT      KVM_X86_FEATURE(CPUID_7_1_EDX, 5)

#define X86_FEATURE_AMX_COMPLEX         KVM_X86_FEATURE(CPUID_7_1_EDX, 8)

#define X86_FEATURE_PREFETCHITI         KVM_X86_FEATURE(CPUID_7_1_EDX, 14)



/* CPUID level 0x80000007 (EDX). */