kvm: x86: Emulate IA32_XFD_ERR for guest

Emulate read/write to IA32_XFD_ERR MSR.

Only the saved value in the guest_fpu container is touched in the
emulation handler. Actual MSR update is handled right before entering
the guest (with preemption disabled)

Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Zeng Guang <guang.zeng@intel.com>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-14-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bb9534590a3a9a267ec203b98b2daff4a1104d16..2475b64cb7621a163f295e6340d9eac6b8b96570 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1377,7 +1377,7 @@ static const u32 msrs_to_save_all[] = {
        MSR_F15H_PERF_CTL3, MSR_F15H_PERF_CTL4, MSR_F15H_PERF_CTL5,
        MSR_F15H_PERF_CTR0, MSR_F15H_PERF_CTR1, MSR_F15H_PERF_CTR2,
        MSR_F15H_PERF_CTR3, MSR_F15H_PERF_CTR4, MSR_F15H_PERF_CTR5,
-       MSR_IA32_XFD,
+       MSR_IA32_XFD, MSR_IA32_XFD_ERR,
 };
 
 static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_all)];
@@ -3699,6 +3699,17 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 
                fpu_update_guest_xfd(&vcpu->arch.guest_fpu, data);
                break;
+       case MSR_IA32_XFD_ERR:
+               if (!msr_info->host_initiated &&
+                   !guest_cpuid_has(vcpu, X86_FEATURE_XFD))
+                       return 1;
+
+               if (data & ~(XFEATURE_MASK_USER_DYNAMIC &
+                            vcpu->arch.guest_supported_xcr0))
+                       return 1;
+
+               vcpu->arch.guest_fpu.xfd_err = data;
+               break;
 #endif
        default:
                if (kvm_pmu_is_valid_msr(vcpu, msr))
@@ -4028,6 +4039,13 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 
                msr_info->data = vcpu->arch.guest_fpu.fpstate->xfd;
                break;
+       case MSR_IA32_XFD_ERR:
+               if (!msr_info->host_initiated &&
+                   !guest_cpuid_has(vcpu, X86_FEATURE_XFD))
+                       return 1;
+
+               msr_info->data = vcpu->arch.guest_fpu.xfd_err;
+               break;
 #endif
        default:
                if (kvm_pmu_is_valid_msr(vcpu, msr_info->index))
@@ -6465,6 +6483,7 @@ static void kvm_init_msr_list(void)
                                continue;
                        break;
                case MSR_IA32_XFD:
+               case MSR_IA32_XFD_ERR:
                        if (!kvm_cpu_cap_has(X86_FEATURE_XFD))
                                continue;
                        break;