linux-kernel - [PATCH v3 20/57] KVM: x86: Do reverse CPUID sanity checks in __feature

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Message-ID: <20241128013424.4096668-21-seanjc@google.com>
Date: Wed, 27 Nov 2024 17:33:47 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Sean Christopherson <seanjc@...gle.com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>, Jarkko Sakkinen <jarkko@...nel.org>
Cc: kvm@...r.kernel.org, linux-sgx@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Maxim Levitsky <mlevitsk@...hat.com>, 
	Hou Wenlong <houwenlong.hwl@...group.com>, Xiaoyao Li <xiaoyao.li@...el.com>, 
	Kechen Lu <kechenl@...dia.com>, Oliver Upton <oliver.upton@...ux.dev>, 
	Binbin Wu <binbin.wu@...ux.intel.com>, Yang Weijiang <weijiang.yang@...el.com>, 
	Robert Hoo <robert.hoo.linux@...il.com>
Subject: [PATCH v3 20/57] KVM: x86: Do reverse CPUID sanity checks in __feature_leaf()

Do the compile-time sanity checks on reverse_cpuid in __feature_leaf() so
that higher level APIs don't need to "manually" perform the sanity checks.

No functional change intended.

Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/cpuid.h         | 3 ---
 arch/x86/kvm/reverse_cpuid.h | 6 ++++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index d4ece5db7b46..5d0fe3793d75 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -179,7 +179,6 @@ static __always_inline void kvm_cpu_cap_clear(unsigned int x86_feature)
 {
 	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
-	reverse_cpuid_check(x86_leaf);
 	kvm_cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature);
 }
 
@@ -187,7 +186,6 @@ static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature)
 {
 	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
-	reverse_cpuid_check(x86_leaf);
 	kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature);
 }
 
@@ -195,7 +193,6 @@ static __always_inline u32 kvm_cpu_cap_get(unsigned int x86_feature)
 {
 	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
-	reverse_cpuid_check(x86_leaf);
 	return kvm_cpu_caps[x86_leaf] & __feature_bit(x86_feature);
 }
 
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index e46220ece83c..1d2db9d529ff 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -145,7 +145,10 @@ static __always_inline u32 __feature_translate(int x86_feature)
 
 static __always_inline u32 __feature_leaf(int x86_feature)
 {
-	return __feature_translate(x86_feature) / 32;
+	u32 x86_leaf = __feature_translate(x86_feature) / 32;
+
+	reverse_cpuid_check(x86_leaf);
+	return x86_leaf;
 }
 
 /*
@@ -168,7 +171,6 @@ static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned int x86_featu
 {
 	unsigned int x86_leaf = __feature_leaf(x86_feature);
 
-	reverse_cpuid_check(x86_leaf);
 	return reverse_cpuid[x86_leaf];
 }
 
-- 
2.47.0.338.g60cca15819-goog