KVM: x86: Handle PKU CPUID adjustment in VMX code

Move the setting of the PKU CPUID bit into VMX to eliminate an instance
of the undesirable "unsigned f_* = *_supported ? F(*) : 0" pattern in
the common CPUID handling code.  Drop ->pku_supported(), CPUID
adjustment was the only user.

Note, some AMD CPUs now support PKU, but SVM doesn't yet support
exposing it to a guest.

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/include/asm/kvm_host.h

@@ -1180,7 +1180,6 @@ struct kvm_x86_ops {
 	bool (*xsaves_supported)(void);
 	bool (*umip_emulated)(void);
 	bool (*pt_supported)(void);
-	bool (*pku_supported)(void);
 
 	int (*check_nested_events)(struct kvm_vcpu *vcpu);
 	void (*request_immediate_exit)(struct kvm_vcpu *vcpu);

arch/x86/kvm/cpuid.c

@@ -333,7 +333,6 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry)
 {
 	unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;
 	unsigned f_la57;
-	unsigned f_pku = kvm_x86_ops->pku_supported() ? F(PKU) : 0;
 
 	/* cpuid 7.0.ebx */
 	const u32 kvm_cpuid_7_0_ebx_x86_features =
@@ -373,10 +372,6 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry)
 		cpuid_entry_mask(entry, CPUID_7_ECX);
 		/* Set LA57 based on hardware capability. */
 		entry->ecx |= f_la57;
-		entry->ecx |= f_pku;
-		/* PKU is not yet implemented for shadow paging. */
-		if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
-			cpuid_entry_clear(entry, X86_FEATURE_PKU);
 
 		entry->edx &= kvm_cpuid_7_0_edx_x86_features;
 		cpuid_entry_mask(entry, CPUID_7_EDX);

arch/x86/kvm/svm.c

@@ -6093,11 +6093,6 @@ static bool svm_has_wbinvd_exit(void)
 	return true;
 }
 
-static bool svm_pku_supported(void)
-{
-	return false;
-}
-
 #define PRE_EX(exit)  { .exit_code = (exit), \
 			.stage = X86_ICPT_PRE_EXCEPT, }
 #define POST_EX(exit) { .exit_code = (exit), \
@@ -7458,7 +7453,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.xsaves_supported = svm_xsaves_supported,
 	.umip_emulated = svm_umip_emulated,
 	.pt_supported = svm_pt_supported,
-	.pku_supported = svm_pku_supported,
 
 	.set_supported_cpuid = svm_set_supported_cpuid,
 

arch/x86/kvm/vmx/capabilities.h

@@ -146,11 +146,6 @@ static inline bool vmx_umip_emulated(void)
 		SECONDARY_EXEC_DESC;
 }
 
-static inline bool vmx_pku_supported(void)
-{
-	return boot_cpu_has(X86_FEATURE_PKU);
-}
-
 static inline bool cpu_has_vmx_rdtscp(void)
 {
 	return vmcs_config.cpu_based_2nd_exec_ctrl &

arch/x86/kvm/vmx/vmx.c

@@ -7137,6 +7137,11 @@ static void vmx_set_supported_cpuid(struct kvm_cpuid_entry2 *entry)
 			cpuid_entry_set(entry, X86_FEATURE_INVPCID);
 		if (vmx_umip_emulated())
 			cpuid_entry_set(entry, X86_FEATURE_UMIP);
+
+		/* PKU is not yet implemented for shadow paging. */
+		if (enable_ept && boot_cpu_has(X86_FEATURE_PKU) &&
+		    boot_cpu_has(X86_FEATURE_OSPKE))
+			cpuid_entry_set(entry, X86_FEATURE_PKU);
 		break;
 	default:
 		break;
@@ -7938,7 +7943,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.xsaves_supported = vmx_xsaves_supported,
 	.umip_emulated = vmx_umip_emulated,
 	.pt_supported = vmx_pt_supported,
-	.pku_supported = vmx_pku_supported,
 
 	.request_immediate_exit = vmx_request_immediate_exit,