KVM: svm: add support for RDTSCP

[mirror_ubuntu-artful-kernel.git] / arch / x86 / kvm / svm.c

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2401fc88905b3f5369d353e41039ef8553e94d8b..af342150558afa146ef70cfc7e6a5fb8223b1dca 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -86,6 +86,7 @@ static const u32 host_save_user_msrs[] = {
        MSR_FS_BASE,
 #endif
        MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
+       MSR_TSC_AUX,
 };
 
 #define NR_HOST_SAVE_USER_MSRS ARRAY_SIZE(host_save_user_msrs)
@@ -135,6 +136,7 @@ struct vcpu_svm {
        uint64_t asid_generation;
        uint64_t sysenter_esp;
        uint64_t sysenter_eip;
+       uint64_t tsc_aux;
 
        u64 next_rip;
 
@@ -1238,6 +1240,9 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
                        wrmsrl(MSR_AMD64_TSC_RATIO, tsc_ratio);
                }
        }
+       /* This assumes that the kernel never uses MSR_TSC_AUX */
+       if (static_cpu_has(X86_FEATURE_RDTSCP))
+               wrmsrl(MSR_TSC_AUX, svm->tsc_aux);
 }
 
 static void svm_vcpu_put(struct kvm_vcpu *vcpu)
@@ -3024,6 +3029,11 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
        case MSR_IA32_SYSENTER_ESP:
                msr_info->data = svm->sysenter_esp;
                break;
+       case MSR_TSC_AUX:
+               if (!boot_cpu_has(X86_FEATURE_RDTSCP))
+                       return 1;
+               msr_info->data = svm->tsc_aux;
+               break;
        /*
         * Nobody will change the following 5 values in the VMCB so we can
         * safely return them on rdmsr. They will always be 0 until LBRV is
@@ -3145,6 +3155,18 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
                svm->sysenter_esp = data;
                svm->vmcb->save.sysenter_esp = data;
                break;
+       case MSR_TSC_AUX:
+               if (!boot_cpu_has(X86_FEATURE_RDTSCP))
+                       return 1;
+
+               /*
+                * This is rare, so we update the MSR here instead of using
+                * direct_access_msrs.  Doing that would require a rdmsr in
+                * svm_vcpu_put.
+                */
+               svm->tsc_aux = data;
+               wrmsrl(MSR_TSC_AUX, svm->tsc_aux);
+               break;
        case MSR_IA32_DEBUGCTLMSR:
                if (!boot_cpu_has(X86_FEATURE_LBRV)) {
                        vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTL 0x%llx, nop\n",
@@ -4041,7 +4063,7 @@ static int svm_get_lpage_level(void)
 
 static bool svm_rdtscp_supported(void)
 {
-       return false;
+       return boot_cpu_has(X86_FEATURE_RDTSCP);
 }
 
 static bool svm_invpcid_supported(void)