linux-kernel - [PATCH v3 26/57] KVM: x86: Handle kernel- and KVM-defined CPUID words in a single helper

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Message-ID: <20241128013424.4096668-27-seanjc@google.com>
Date: Wed, 27 Nov 2024 17:33:53 -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 26/57] KVM: x86: Handle kernel- and KVM-defined CPUID words
 in a single helper

Merge kvm_cpu_cap_init() and kvm_cpu_cap_init_kvm_defined() into a single
helper.  The only advantage of separating the two was to make it somewhat
obvious that KVM directly initializes the KVM-defined words, whereas using
a common helper will allow for hardening both kernel- and KVM-defined
CPUID words without needing copy+paste.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/cpuid.c | 46 +++++++++++++++-----------------------------
 1 file changed, 16 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index ddff0c7c78b9..73e756d097e4 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -602,37 +602,23 @@ static __always_inline u32 raw_cpuid_get(struct cpuid_reg cpuid)
 	return *__cpuid_entry_get_reg(&entry, cpuid.reg);
 }
 
-/* Mask kvm_cpu_caps for @leaf with the raw CPUID capabilities of this CPU. */
-static __always_inline void __kvm_cpu_cap_mask(unsigned int leaf)
+static __always_inline void kvm_cpu_cap_init(u32 leaf, u32 mask)
 {
 	const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32);
 
-	reverse_cpuid_check(leaf);
+	/*
+	 * For kernel-defined leafs, mask the boot CPU's pre-populated value.
+	 * For KVM-defined leafs, explicitly set the leaf, as KVM is the one
+	 * and only authority.
+	 */
+	if (leaf < NCAPINTS)
+		kvm_cpu_caps[leaf] &= mask;
+	else
+		kvm_cpu_caps[leaf] = mask;
 
 	kvm_cpu_caps[leaf] &= raw_cpuid_get(cpuid);
 }
 
-static __always_inline
-void kvm_cpu_cap_init_kvm_defined(enum kvm_only_cpuid_leafs leaf, u32 mask)
-{
-	/* Use kvm_cpu_cap_init for leafs that aren't KVM-only. */
-	BUILD_BUG_ON(leaf < NCAPINTS);
-
-	kvm_cpu_caps[leaf] = mask;
-
-	__kvm_cpu_cap_mask(leaf);
-}
-
-static __always_inline void kvm_cpu_cap_init(enum cpuid_leafs leaf, u32 mask)
-{
-	/* Use kvm_cpu_cap_init_kvm_defined for KVM-only leafs. */
-	BUILD_BUG_ON(leaf >= NCAPINTS);
-
-	kvm_cpu_caps[leaf] &= mask;
-
-	__kvm_cpu_cap_mask(leaf);
-}
-
 #define F feature_bit
 
 /* Scattered Flag - For features that are scattered by cpufeatures.h. */
@@ -843,7 +829,7 @@ void kvm_set_cpu_caps(void)
 		F(LAM)
 	);
 
-	kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,
+	kvm_cpu_cap_init(CPUID_7_1_EDX,
 		F(AVX_VNNI_INT8) |
 		F(AVX_NE_CONVERT) |
 		F(AMX_COMPLEX) |
@@ -852,7 +838,7 @@ void kvm_set_cpu_caps(void)
 		F(AVX10)
 	);
 
-	kvm_cpu_cap_init_kvm_defined(CPUID_7_2_EDX,
+	kvm_cpu_cap_init(CPUID_7_2_EDX,
 		F(INTEL_PSFD) |
 		F(IPRED_CTRL) |
 		F(RRSBA_CTRL) |
@@ -869,13 +855,13 @@ void kvm_set_cpu_caps(void)
 		X86_64_F(XFD)
 	);
 
-	kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX,
+	kvm_cpu_cap_init(CPUID_12_EAX,
 		SF(SGX1) |
 		SF(SGX2) |
 		SF(SGX_EDECCSSA)
 	);
 
-	kvm_cpu_cap_init_kvm_defined(CPUID_24_0_EBX,
+	kvm_cpu_cap_init(CPUID_24_0_EBX,
 		F(AVX10_128) |
 		F(AVX10_256) |
 		F(AVX10_512)
@@ -938,7 +924,7 @@ void kvm_set_cpu_caps(void)
 	if (!tdp_enabled && IS_ENABLED(CONFIG_X86_64))
 		kvm_cpu_cap_set(X86_FEATURE_GBPAGES);
 
-	kvm_cpu_cap_init_kvm_defined(CPUID_8000_0007_EDX,
+	kvm_cpu_cap_init(CPUID_8000_0007_EDX,
 		SF(CONSTANT_TSC)
 	);
 
@@ -1012,7 +998,7 @@ void kvm_set_cpu_caps(void)
 	kvm_cpu_cap_check_and_set(X86_FEATURE_IBPB_BRTYPE);
 	kvm_cpu_cap_check_and_set(X86_FEATURE_SRSO_NO);
 
-	kvm_cpu_cap_init_kvm_defined(CPUID_8000_0022_EAX,
+	kvm_cpu_cap_init(CPUID_8000_0022_EAX,
 		F(PERFMON_V2)
 	);
 
-- 
2.47.0.338.g60cca15819-goog