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KVM: x86: Advertise AMX-COMPLEX CPUID to userspace

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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: Tao Su <tao1.su@linux.intel.com>
Reviewed-by: Xiaoyao 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: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Tao Su 2023-08-02 10:29:54 +08:00 committed by Sean Christopherson
parent a788fbb763
commit 99b6685453
2 changed files with 3 additions and 1 deletions
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3
arch/x86/kvm/cpuid.c
View File

@ -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,

1
arch/x86/kvm/reverse_cpuid.h
View File

@ -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). */