KVM: x86: Override host CPUID results with kvm_cpu_caps

Override CPUID entries with kvm_cpu_caps during KVM_GET_SUPPORTED_CPUID
instead of masking the host CPUID result, which is redundant now that
the host CPUID is incorporated into kvm_cpu_caps at runtime.

No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/cpuid.c

@@ -485,8 +485,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = min(entry->eax, 0x1fU);
 		break;
 	case 1:
-		cpuid_entry_mask(entry, CPUID_1_EDX);
-		cpuid_entry_mask(entry, CPUID_1_ECX);
+		cpuid_entry_override(entry, CPUID_1_EDX);
+		cpuid_entry_override(entry, CPUID_1_ECX);
 		/* we support x2apic emulation even if host does not support
 		 * it since we emulate x2apic in software */
 		cpuid_entry_set(entry, X86_FEATURE_X2APIC);
@@ -531,9 +531,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 	/* function 7 has additional index. */
 	case 7:
 		entry->eax = min(entry->eax, 1u);
-		cpuid_entry_mask(entry, CPUID_7_0_EBX);
-		cpuid_entry_mask(entry, CPUID_7_ECX);
-		cpuid_entry_mask(entry, CPUID_7_EDX);
+		cpuid_entry_override(entry, CPUID_7_0_EBX);
+		cpuid_entry_override(entry, CPUID_7_ECX);
+		cpuid_entry_override(entry, CPUID_7_EDX);
 
 		/* TSC_ADJUST and ARCH_CAPABILITIES are emulated in software. */
 		cpuid_entry_set(entry, X86_FEATURE_TSC_ADJUST);
@@ -552,7 +552,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			if (!entry)
 				goto out;
 
-			cpuid_entry_mask(entry, CPUID_7_1_EAX);
+			cpuid_entry_override(entry, CPUID_7_1_EAX);
 			entry->ebx = 0;
 			entry->ecx = 0;
 			entry->edx = 0;
@@ -618,7 +618,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		if (!entry)
 			goto out;
 
-		cpuid_entry_mask(entry, CPUID_D_1_EAX);
+		cpuid_entry_override(entry, CPUID_D_1_EAX);
 		if (entry->eax & (F(XSAVES)|F(XSAVEC)))
 			entry->ebx = xstate_required_size(supported_xcr0, true);
 		else
@@ -697,11 +697,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = min(entry->eax, 0x8000001f);
 		break;
 	case 0x80000001:
-		cpuid_entry_mask(entry, CPUID_8000_0001_EDX);
-		/* Add it manually because it may not be in host CPUID.  */
-		if (!tdp_enabled)
-			cpuid_entry_set(entry, X86_FEATURE_GBPAGES);
-		cpuid_entry_mask(entry, CPUID_8000_0001_ECX);
+		cpuid_entry_override(entry, CPUID_8000_0001_EDX);
+		cpuid_entry_override(entry, CPUID_8000_0001_ECX);
 		break;
 	case 0x80000007: /* Advanced power management */
 		/* invariant TSC is CPUID.80000007H:EDX[8] */
@@ -719,7 +716,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			g_phys_as = phys_as;
 		entry->eax = g_phys_as | (virt_as << 8);
 		entry->edx = 0;
-		cpuid_entry_mask(entry, CPUID_8000_0008_EBX);
+		cpuid_entry_override(entry, CPUID_8000_0008_EBX);
 		/*
 		 * AMD has separate bits for each SPEC_CTRL bit.
 		 * arch/x86/kernel/cpu/bugs.c is kind enough to
@@ -761,7 +758,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = min(entry->eax, 0xC0000004);
 		break;
 	case 0xC0000001:
-		cpuid_entry_mask(entry, CPUID_C000_0001_EDX);
+		cpuid_entry_override(entry, CPUID_C000_0001_EDX);
 		break;
 	case 3: /* Processor serial number */
 	case 5: /* MONITOR/MWAIT */

arch/x86/kvm/cpuid.h

@@ -170,13 +170,13 @@ static __always_inline void cpuid_entry_change(struct kvm_cpuid_entry2 *entry,
 		*reg &= ~__feature_bit(x86_feature);
 }
 
-static __always_inline void cpuid_entry_mask(struct kvm_cpuid_entry2 *entry,
+static __always_inline void cpuid_entry_override(struct kvm_cpuid_entry2 *entry,
 						 enum cpuid_leafs leaf)
 {
 	u32 *reg = cpuid_entry_get_reg(entry, leaf * 32);
 
 	BUILD_BUG_ON(leaf >= ARRAY_SIZE(kvm_cpu_caps));
-	*reg &= kvm_cpu_caps[leaf];
+	*reg = kvm_cpu_caps[leaf];
 }
 
 static __always_inline u32 *guest_cpuid_get_register(struct kvm_vcpu *vcpu,

arch/x86/kvm/svm.c

@@ -6072,8 +6072,7 @@ static void svm_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 		entry->ebx = 8; /* Lets support 8 ASIDs in case we add proper
 				   ASID emulation to nested SVM */
 		entry->ecx = 0; /* Reserved */
-		/* Note, 0x8000000A.EDX is managed via kvm_cpu_caps. */;
-		cpuid_entry_mask(entry, CPUID_8000_000A_EDX);
+		cpuid_entry_override(entry, CPUID_8000_000A_EDX);
 		break;
 	}
 }

arch/x86/kvm/vmx/vmx.c

@@ -7130,18 +7130,6 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
  */
 static void vmx_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 {
-	switch (entry->function) {
-	case 0x7:
-		/*
-		 * UMIP needs to be manually set even though vmx_set_cpu_caps()
-		 * also sets UMIP since do_host_cpuid() will drop it.
-		 */
-		if (vmx_umip_emulated())
-			cpuid_entry_set(entry, X86_FEATURE_UMIP);
-		break;
-	default:
-		break;
-	}
 }
 
 static __init void vmx_set_cpu_caps(void)