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Message-Id: <20221125125845.1182922-9-jiaxi.chen@linux.intel.com>
Date: Fri, 25 Nov 2022 20:58:45 +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 v5 8/8] 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@...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 c4ea8f593b72..f60e9fa1b777 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;
--
2.27.0
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