linux-kernel - [RFC PATCH 09/22] KVM: x86: Introduce KVM_X86_FEATURE

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Message-ID: <20241121185315.3416855-10-mizhang@google.com>
Date: Thu, 21 Nov 2024 18:53:01 +0000
From: Mingwei Zhang <mizhang@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Huang Rui <ray.huang@....com>, "Gautham R. Shenoy" <gautham.shenoy@....com>, 
	Mario Limonciello <mario.limonciello@....com>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Viresh Kumar <viresh.kumar@...aro.org>, 
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>, Len Brown <lenb@...nel.org>
Cc: "H. Peter Anvin" <hpa@...or.com>, Perry Yuan <perry.yuan@....com>, kvm@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, 
	Jim Mattson <jmattson@...gle.com>, Mingwei Zhang <mizhang@...gle.com>
Subject: [RFC PATCH 09/22] KVM: x86: Introduce KVM_X86_FEATURE_APERFMPERF

The APERFMPERF feature bit appears in CPUID.6H:ECX[0], but is exposed to
Linux via X86_FEATURE_APERFMPERF in a Linux-defined feature word. To
enable KVM's reverse CPUID functionality for this feature, define a KVM
feature word matching the hardware CPUID leaf that contains the APERFMPERF
bit.

This patch only adds the feature definition - enabling and advertising
the feature to guests will be handled in later patches.

Signed-off-by: Mingwei Zhang <mizhang@...gle.com>
Co-developed-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Jim Mattson <jmattson@...gle.com>
---
 arch/x86/kvm/reverse_cpuid.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index 0d17d6b706396..d12e5d9ab2251 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -18,6 +18,7 @@ enum kvm_only_cpuid_leafs {
 	CPUID_8000_0022_EAX,
 	CPUID_7_2_EDX,
 	CPUID_24_0_EBX,
+	CPUID_6_ECX,
 	NR_KVM_CPU_CAPS,
 
 	NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
@@ -42,6 +43,9 @@ enum kvm_only_cpuid_leafs {
 #define KVM_X86_FEATURE_SGX2		KVM_X86_FEATURE(CPUID_12_EAX, 1)
 #define KVM_X86_FEATURE_SGX_EDECCSSA	KVM_X86_FEATURE(CPUID_12_EAX, 11)
 
+/* Intel-defined sub-features, CPUID level 0x00000006 (ECX) */
+#define KVM_X86_FEATURE_APERFMPERF	KVM_X86_FEATURE(CPUID_6_ECX, 0)
+
 /* 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)
@@ -98,6 +102,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
 	[CPUID_8000_0022_EAX] = {0x80000022, 0, CPUID_EAX},
 	[CPUID_7_2_EDX]       = {         7, 2, CPUID_EDX},
 	[CPUID_24_0_EBX]      = {      0x24, 0, CPUID_EBX},
+	[CPUID_6_ECX]         = {         6, 0, CPUID_ECX},
 };
 
 /*
@@ -135,6 +140,7 @@ static __always_inline u32 __feature_translate(int x86_feature)
 	KVM_X86_TRANSLATE_FEATURE(SGX_EDECCSSA);
 	KVM_X86_TRANSLATE_FEATURE(CONSTANT_TSC);
 	KVM_X86_TRANSLATE_FEATURE(PERFMON_V2);
+	KVM_X86_TRANSLATE_FEATURE(APERFMPERF);
 	KVM_X86_TRANSLATE_FEATURE(RRSBA_CTRL);
 	KVM_X86_TRANSLATE_FEATURE(BHI_CTRL);
 	default:
-- 
2.47.0.371.ga323438b13-goog