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.

Link: https://lore.kernel.org/r/20241128013424.4096668-27-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 11cd176a26f8fcb3f453db182391d0c6d2fa6733..2cd06155684ef10016ca57936f0340537263f7a5 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -623,37 +623,23 @@ 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. */
@@ -864,7 +850,7 @@ 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) |
@@ -873,7 +859,7 @@ 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) |
@@ -890,13 +876,13 @@ 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)
@@ -959,7 +945,7 @@ 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)
        );
 
@@ -1033,7 +1019,7 @@ 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)
        );