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| author | Jiaxi Chen <jiaxi.chen@linux.intel.com> | 2022-11-25 20:58:45 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-11-28 13:33:30 -0500 |
| commit | 29c46979b25d5ca867e9859bfdd088d028739cdf (patch) | |
| tree | 5058c82c12f5eb7c248b7e656948e539a20abcf2 | |
| parent | 9977f0877de7f8fc51391e2d52bc993efbd58b90 (diff) | |
| download | lwn-29c46979b25d5ca867e9859bfdd088d028739cdf.tar.gz lwn-29c46979b25d5ca867e9859bfdd088d028739cdf.zip | |
KVM: x86: Advertise PREFETCHIT0/1 CPUID to user space
Latest Intel platform Granite Rapids has introduced a new instruction -
PREFETCHIT0/1, which moves code to memory (cache) closer to the
processor depending on specific hints.
The bit definition:
CPUID.(EAX=7,ECX=1):EDX[bit 14]
PREFETCHIT0/1 is on a KVM-only subleaf. Plus an x86_FEATURE definition
for this feature bit to direct it to the KVM entry.
Advertise PREFETCHIT0/1 to KVM userspace. This is safe because there are
no new VMX controls or additional host enabling required for guests to
use this feature.
Signed-off-by: Jiaxi Chen <jiaxi.chen@linux.intel.com>
Message-Id: <20221125125845.1182922-9-jiaxi.chen@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/reverse_cpuid.h | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 5a95624a658a..723502181a3a 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -668,7 +668,7 @@ 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(AVX_VNNI_INT8) | F(AVX_NE_CONVERT) | F(PREFETCHITI) ); 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 43eff7207e01..203fdad07bae 100644 --- a/arch/x86/kvm/reverse_cpuid.h +++ b/arch/x86/kvm/reverse_cpuid.h @@ -40,6 +40,7 @@ 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_PREFETCHITI KVM_X86_FEATURE(CPUID_7_1_EDX, 14) struct cpuid_reg { u32 function; |