[PATCH v3 7/7] x86: KVM: Advertise PREFETCHIT0/1 CPUID to user space

Jiaxi Chen
2022-11-10T01:55:25Z

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]

This CPUID is exposed to user space. Besides, there is no other VMX
control for this instruction.

Signed-off-by: Jiaxi Chen <jiaxi.chen@linux.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 47ac2a502d91..9021a80b3553 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -662,7 +662,7 @@ void kvm_set_cpu_caps(void)
);

kvm_cpu_cap_init_scattered(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 b8addd85b062..884aebe7b3c2 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -36,6 +36,7 @@ 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)