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| author | Jing Liu <jing2.liu@linux.intel.com> | 2019-07-11 13:49:57 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-15 12:49:30 +0200 |
| commit | 0b774629512057b4becc705e2495220844e6e795 (patch) | |
| tree | d2e505c37161a274d8655acac0d727a7300b1582 | |
| parent | 964a4eacef67503a1154f7e0a75f52fbdce52022 (diff) | |
| download | linux-0b774629512057b4becc705e2495220844e6e795.tar.bz2 | |
KVM: x86: expose AVX512_BF16 feature to guest
AVX512 BFLOAT16 instructions support 16-bit BFLOAT16 floating-point
format (BF16) for deep learning optimization.
Intel adds AVX512 BFLOAT16 feature in CooperLake, which is CPUID.7.1.EAX[5].
Detailed information of the CPUID bit can be found here,
https://software.intel.com/sites/default/files/managed/c5/15/\
architecture-instruction-set-extensions-programming-reference.pdf.
Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
[Fix type mismatch in min, changing constant "1" to "1u". - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index ead681210306..22c2720cd948 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -368,9 +368,13 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index) F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) | F(MD_CLEAR); + /* cpuid 7.1.eax */ + const u32 kvm_cpuid_7_1_eax_x86_features = + F(AVX512_BF16); + switch (index) { case 0: - entry->eax = 0; + entry->eax = min(entry->eax, 1u); entry->ebx &= kvm_cpuid_7_0_ebx_x86_features; cpuid_mask(&entry->ebx, CPUID_7_0_EBX); /* TSC_ADJUST is emulated */ @@ -394,6 +398,12 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index) */ entry->edx |= F(ARCH_CAPABILITIES); break; + case 1: + entry->eax &= kvm_cpuid_7_1_eax_x86_features; + entry->ebx = 0; + entry->ecx = 0; + entry->edx = 0; + break; default: WARN_ON_ONCE(1); entry->eax = 0; |