[PATCH v6 13/21] kvm: x86: Emulate IA32_XFD_ERR for guest

Paolo Bonzini
2022-01-07T18:56:29Z

From: Jing Liu <jing2.liu@intel.com>

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: 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>
---
arch/x86/kvm/x86.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bb9534590a3a..2475b64cb762 100644
--- 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;
--
2.31.1