KVM: x86: Use KVM cpu caps to detect MSR_TSC_AUX virt support

Check for MSR_TSC_AUX virtualization via kvm_cpu_cap_has() and drop
->rdtscp_supported().

Note, vmx_rdtscp_supported() needs to hang around a tiny bit longer due
other usage in VMX code.

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

@@ -1156,7 +1156,6 @@ struct kvm_x86_ops {
 	int (*get_tdp_level)(struct kvm_vcpu *vcpu);
 	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
 	int (*get_lpage_level)(void);
-	bool (*rdtscp_supported)(void);
 
 	void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
 

arch/x86/kvm/svm.c

@@ -6074,11 +6074,6 @@ static int svm_get_lpage_level(void)
 	return PT_PDPE_LEVEL;
 }
 
-static bool svm_rdtscp_supported(void)
-{
-	return boot_cpu_has(X86_FEATURE_RDTSCP);
-}
-
 static bool svm_pt_supported(void)
 {
 	return false;
@@ -7445,7 +7440,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 
 	.cpuid_update = svm_cpuid_update,
 
-	.rdtscp_supported = svm_rdtscp_supported,
 	.pt_supported = svm_pt_supported,
 
 	.set_supported_cpuid = svm_set_supported_cpuid,

arch/x86/kvm/vmx/vmx.c

@@ -7939,9 +7939,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.get_lpage_level = vmx_get_lpage_level,
 
 	.cpuid_update = vmx_cpuid_update,
-
-	.rdtscp_supported = vmx_rdtscp_supported,
-
 	.set_supported_cpuid = vmx_set_supported_cpuid,
 
 	.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,

arch/x86/kvm/x86.c

@@ -5215,7 +5215,7 @@ static void kvm_init_msr_list(void)
 				continue;
 			break;
 		case MSR_TSC_AUX:
-			if (!kvm_x86_ops->rdtscp_supported())
+			if (!kvm_cpu_cap_has(X86_FEATURE_RDTSCP))
 				continue;
 			break;
 		case MSR_IA32_RTIT_CTL: