linux-kernel - [PATCH v4 10/12] KVM: x86/cpuid: Add X86_FEATURE_PERFMON

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Message-Id: <20230214050757.9623-11-likexu@tencent.com>
Date:   Tue, 14 Feb 2023 13:07:55 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 10/12] KVM: x86/cpuid: Add X86_FEATURE_PERFMON_V2 as a scattered flag

From: Like Xu <likexu@...cent.com>

Considering that the core kernel may also want to know this flag, to avoid
confusion this needs to be a scattered flag rather than a pure KVM flag so
that KVM can redirect it to the hardware-defined bit position, which is the
role of __feature_translate() and KVM_X86_FEATURE_PERFMON_V2.

Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Like Xu <likexu@...cent.com>
---
 arch/x86/kvm/reverse_cpuid.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index 4945456fd646..333e28b0a13c 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -15,6 +15,7 @@ enum kvm_only_cpuid_leafs {
 	CPUID_12_EAX	 = NCAPINTS,
 	CPUID_7_1_EDX,
 	CPUID_8000_0007_EDX,
+	CPUID_8000_0022_EAX,
 	NR_KVM_CPU_CAPS,
 
 	NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
@@ -47,6 +48,9 @@ enum kvm_only_cpuid_leafs {
 /* CPUID level 0x80000007 (EDX). */
 #define KVM_X86_FEATURE_CONSTANT_TSC	KVM_X86_FEATURE(CPUID_8000_0007_EDX, 8)
 
+/* CPUID level 0x80000022 (EAX) */
+#define KVM_X86_FEATURE_PERFMON_V2	KVM_X86_FEATURE(CPUID_8000_0022_EAX, 0)
+
 struct cpuid_reg {
 	u32 function;
 	u32 index;
@@ -73,6 +77,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
 	[CPUID_8000_001F_EAX] = {0x8000001f, 0, CPUID_EAX},
 	[CPUID_7_1_EDX]       = {         7, 1, CPUID_EDX},
 	[CPUID_8000_0007_EDX] = {0x80000007, 0, CPUID_EDX},
+	[CPUID_8000_0022_EAX] = {0x80000022, 0, CPUID_EAX},
 };
 
 /*
@@ -107,6 +112,8 @@ static __always_inline u32 __feature_translate(int x86_feature)
 		return KVM_X86_FEATURE_SGX_EDECCSSA;
 	else if (x86_feature == X86_FEATURE_CONSTANT_TSC)
 		return KVM_X86_FEATURE_CONSTANT_TSC;
+	else if (x86_feature == X86_FEATURE_PERFMON_V2)
+		return KVM_X86_FEATURE_PERFMON_V2;
 
 	return x86_feature;
 }
-- 
2.39.1