KVM: x86: Set emulated/transmuted feature bits via kvm_cpu_caps

Set emulated and transmuted (set based on other features) feature bits
via kvm_cpu_caps now that the CPUID output for KVM_GET_SUPPORTED_CPUID
is direcly overidden with kvm_cpu_caps.

Note, VMX emulation of UMIP already sets kvm_cpu_caps.

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

arch/x86/kvm/cpuid.c

@@ -306,6 +306,8 @@ void kvm_set_cpu_caps(void)
 		0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
 		F(F16C) | F(RDRAND)
 	);
+	/* KVM emulates x2apic in software irrespective of host support. */
+	kvm_cpu_cap_set(X86_FEATURE_X2APIC);
 
 	kvm_cpu_cap_mask(CPUID_1_EDX,
 		F(FPU) | F(VME) | F(DE) | F(PSE) |
@@ -342,6 +344,17 @@ void kvm_set_cpu_caps(void)
 		F(MD_CLEAR)
 	);
 
+	/* TSC_ADJUST and ARCH_CAPABILITIES are emulated in software. */
+	kvm_cpu_cap_set(X86_FEATURE_TSC_ADJUST);
+	kvm_cpu_cap_set(X86_FEATURE_ARCH_CAPABILITIES);
+
+	if (boot_cpu_has(X86_FEATURE_IBPB) && boot_cpu_has(X86_FEATURE_IBRS))
+		kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL);
+	if (boot_cpu_has(X86_FEATURE_STIBP))
+		kvm_cpu_cap_set(X86_FEATURE_INTEL_STIBP);
+	if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
+		kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD);
+
 	kvm_cpu_cap_mask(CPUID_7_1_EAX,
 		F(AVX512_BF16)
 	);
@@ -378,6 +391,29 @@ void kvm_set_cpu_caps(void)
 		F(AMD_SSB_NO) | F(AMD_STIBP) | F(AMD_STIBP_ALWAYS_ON)
 	);
 
+	/*
+	 * AMD has separate bits for each SPEC_CTRL bit.
+	 * arch/x86/kernel/cpu/bugs.c is kind enough to
+	 * record that in cpufeatures so use them.
+	 */
+	if (boot_cpu_has(X86_FEATURE_IBPB))
+		kvm_cpu_cap_set(X86_FEATURE_AMD_IBPB);
+	if (boot_cpu_has(X86_FEATURE_IBRS))
+		kvm_cpu_cap_set(X86_FEATURE_AMD_IBRS);
+	if (boot_cpu_has(X86_FEATURE_STIBP))
+		kvm_cpu_cap_set(X86_FEATURE_AMD_STIBP);
+	if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
+		kvm_cpu_cap_set(X86_FEATURE_AMD_SSBD);
+	if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
+		kvm_cpu_cap_set(X86_FEATURE_AMD_SSB_NO);
+	/*
+	 * The preference is to use SPEC CTRL MSR instead of the
+	 * VIRT_SPEC MSR.
+	 */
+	if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) &&
+	    !boot_cpu_has(X86_FEATURE_AMD_SSBD))
+		kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
+
 	/*
 	 * Hide all SVM features by default, SVM will set the cap bits for
 	 * features it emulates and/or exposes for L1.
@@ -487,9 +523,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 	case 1:
 		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);
 		break;
 	case 2:
 		/*
@@ -535,17 +568,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		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);
-		cpuid_entry_set(entry, X86_FEATURE_ARCH_CAPABILITIES);
-
-		if (boot_cpu_has(X86_FEATURE_IBPB) && boot_cpu_has(X86_FEATURE_IBRS))
-			cpuid_entry_set(entry, X86_FEATURE_SPEC_CTRL);
-		if (boot_cpu_has(X86_FEATURE_STIBP))
-			cpuid_entry_set(entry, X86_FEATURE_INTEL_STIBP);
-		if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
-			cpuid_entry_set(entry, X86_FEATURE_SPEC_CTRL_SSBD);
-
 		/* KVM only supports 0x7.0 and 0x7.1, capped above via min(). */
 		if (entry->eax == 1) {
 			entry = do_host_cpuid(array, function, 1);
@@ -717,28 +739,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = g_phys_as | (virt_as << 8);
 		entry->edx = 0;
 		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
-		 * record that in cpufeatures so use them.
-		 */
-		if (boot_cpu_has(X86_FEATURE_IBPB))
-			cpuid_entry_set(entry, X86_FEATURE_AMD_IBPB);
-		if (boot_cpu_has(X86_FEATURE_IBRS))
-			cpuid_entry_set(entry, X86_FEATURE_AMD_IBRS);
-		if (boot_cpu_has(X86_FEATURE_STIBP))
-			cpuid_entry_set(entry, X86_FEATURE_AMD_STIBP);
-		if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
-			cpuid_entry_set(entry, X86_FEATURE_AMD_SSBD);
-		if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
-			cpuid_entry_set(entry, X86_FEATURE_AMD_SSB_NO);
-		/*
-		 * The preference is to use SPEC CTRL MSR instead of the
-		 * VIRT_SPEC MSR.
-		 */
-		if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) &&
-		    !boot_cpu_has(X86_FEATURE_AMD_SSBD))
-			cpuid_entry_set(entry, X86_FEATURE_VIRT_SSBD);
 		break;
 	}
 	case 0x80000019:

arch/x86/kvm/svm.c

@@ -1375,6 +1375,11 @@ static __init void svm_set_cpu_caps(void)
 	if (nested)
 		kvm_cpu_cap_set(X86_FEATURE_SVM);
 
+	/* CPUID 0x80000008 */
+	if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) ||
+	    boot_cpu_has(X86_FEATURE_AMD_SSBD))
+		kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
+
 	/* CPUID 0x8000000A */
 	/* Support next_rip if host supports it */
 	kvm_cpu_cap_check_and_set(X86_FEATURE_NRIPS);
@@ -6051,22 +6056,9 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu)
 					 APICV_INHIBIT_REASON_NESTED);
 }
 
-/*
- * Vendor specific emulation must be handled via ->set_supported_cpuid(), not
- * svm_set_cpu_caps(), as capabilities configured during hardware_setup() are
- * masked against hardware/kernel support, i.e. they'd be lost.
- *
- * Note, setting a flag based on a *different* feature, e.g. setting VIRT_SSBD
- * if LS_CFG_SSBD or AMD_SSBD is supported, is effectively emulation.
- */
 static void svm_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 {
 	switch (entry->function) {
-	case 0x80000008:
-		if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) ||
-		    boot_cpu_has(X86_FEATURE_AMD_SSBD))
-			cpuid_entry_set(entry, X86_FEATURE_VIRT_SSBD);
-		break;
 	case 0x8000000A:
 		entry->eax = 1; /* SVM revision 1 */
 		entry->ebx = 8; /* Lets support 8 ASIDs in case we add proper

arch/x86/kvm/vmx/vmx.c

@@ -7123,11 +7123,6 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 	}
 }
 
-/*
- * Vendor specific emulation must be handled via ->set_supported_cpuid(), not
- * vmx_set_cpu_caps(), as capabilities configured during hardware_setup() are
- * masked against hardware/kernel support, i.e. they'd be lost.
- */
 static void vmx_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 {
 }