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Date: Thu, 3 Nov 2022 10:50:26 +0800 From: Jiaxi Chen <jiaxi.chen@...ux.intel.com> To: kvm@...r.kernel.org Cc: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com, seanjc@...gle.com, pbonzini@...hat.com, ndesaulniers@...gle.com, alexandre.belloni@...tlin.com, peterz@...radead.org, jpoimboe@...nel.org, chang.seok.bae@...el.com, pawan.kumar.gupta@...ux.intel.com, babu.moger@....com, jmattson@...gle.com, sandipan.das@....com, tony.luck@...el.com, sathyanarayanan.kuppuswamy@...ux.intel.com, fenghua.yu@...el.com, keescook@...omium.org, nathan@...nel.org, linux-kernel@...r.kernel.org Subject: [PATCH v2 4/8] x86: KVM: Advertise AMX-FP16 CPUID to user space Latest Intel platform Granite Rapids has introduced a new instruction - AMX-FP16, which performs dot-products of two FP16 tiles and accumulates the results into a packed single precision tile. This instrucion needs no additional enabling on top of the existing kernel AMX enabling. AMX-FP16 adds FP16 capability and also allows a FP16 GPU trained model to run faster without loss of accuracy or added SW overhead. The bit definition: CPUID.(EAX=7,ECX=1):EAX[bit 21] This CPUID is exposed to user space. Besides, there is no other VMX control for this instruction. Signed-off-by: Jiaxi Chen <jiaxi.chen@...ux.intel.com> --- arch/x86/kvm/cpuid.c | 2 +- arch/x86/kvm/reverse_cpuid.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index b388ef52f8c8..19ef02d5b11b 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -657,7 +657,7 @@ void kvm_set_cpu_caps(void) kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD); kvm_cpu_cap_init_scattered(CPUID_7_1_EAX, - F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) + F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) | F(AMX_FP16) ); kvm_cpu_cap_mask(CPUID_D_1_EAX, diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h index 24f570ddb225..05fd43ebd226 100644 --- a/arch/x86/kvm/reverse_cpuid.h +++ b/arch/x86/kvm/reverse_cpuid.h @@ -29,6 +29,7 @@ enum kvm_only_cpuid_leafs { #define X86_FEATURE_AVX_VNNI KVM_X86_FEATURE(CPUID_7_1_EAX, 4) #define X86_FEATURE_AVX512_BF16 KVM_X86_FEATURE(CPUID_7_1_EAX, 5) #define X86_FEATURE_CMPCCXADD KVM_X86_FEATURE(CPUID_7_1_EAX, 7) +#define X86_FEATURE_AMX_FP16 KVM_X86_FEATURE(CPUID_7_1_EAX, 21) struct cpuid_reg { u32 function; -- 2.27.0
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