KVM: x86: Add MSR_AMD64_DC_CFG to the list of ignored MSRs

Hyper-V writes 0x800000000000 to MSR_AMD64_DC_CFG when running on AMD CPUs
as recommended in erratum 383, analogous to our svm_init_erratum_383.

By ignoring the MSR, this patch enables running Hyper-V in L1 on AMD.
Signed-off-by: NLadi Prosek <lprosek@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/x86.c

@@ -2137,6 +2137,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_VM_HSAVE_PA:
 	case MSR_AMD64_PATCH_LOADER:
 	case MSR_AMD64_BU_CFG2:
+	case MSR_AMD64_DC_CFG:
 		break;
 
 	case MSR_EFER:
@@ -2399,6 +2400,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_FAM10H_MMIO_CONF_BASE:
 	case MSR_AMD64_BU_CFG2:
 	case MSR_IA32_PERF_CTL:
+	case MSR_AMD64_DC_CFG:
 		msr_info->data = 0;
 		break;
 	case MSR_K7_EVNTSEL0 ... MSR_K7_EVNTSEL3: