diff options
Diffstat (limited to 'arch/x86/kvm/hyperv.c')
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 4943f6b2bb..8a47f8541e 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1322,6 +1322,56 @@ static bool hv_check_msr_access(struct kvm_vcpu_hv *hv_vcpu, u32 msr) return false; } +#define KVM_HV_WIN2016_GUEST_ID 0x1040a00003839 +#define KVM_HV_WIN2016_GUEST_ID_MASK (~GENMASK_ULL(23, 16)) /* mask out the service version */ + +/* + * Hyper-V enabled Windows Server 2016 SMP VMs fail to boot in !XSAVES && XSAVEC + * configuration. + * Such configuration can result from, for example, AMD Erratum 1386 workaround. + * + * Print a notice so users aren't left wondering what's suddenly gone wrong. + */ +static void __kvm_hv_xsaves_xsavec_maybe_warn(struct kvm_vcpu *vcpu) +{ + struct kvm *kvm = vcpu->kvm; + struct kvm_hv *hv = to_kvm_hv(kvm); + + /* Check again under the hv_lock. */ + if (hv->xsaves_xsavec_checked) + return; + + if ((hv->hv_guest_os_id & KVM_HV_WIN2016_GUEST_ID_MASK) != + KVM_HV_WIN2016_GUEST_ID) + return; + + hv->xsaves_xsavec_checked = true; + + /* UP configurations aren't affected */ + if (atomic_read(&kvm->online_vcpus) < 2) + return; + + if (guest_cpuid_has(vcpu, X86_FEATURE_XSAVES) || + !guest_cpuid_has(vcpu, X86_FEATURE_XSAVEC)) + return; + + pr_notice_ratelimited("Booting SMP Windows KVM VM with !XSAVES && XSAVEC. " + "If it fails to boot try disabling XSAVEC in the VM config.\n"); +} + +void kvm_hv_xsaves_xsavec_maybe_warn(struct kvm_vcpu *vcpu) +{ + struct kvm_hv *hv = to_kvm_hv(vcpu->kvm); + + if (!vcpu->arch.hyperv_enabled || + hv->xsaves_xsavec_checked) + return; + + mutex_lock(&hv->hv_lock); + __kvm_hv_xsaves_xsavec_maybe_warn(vcpu); + mutex_unlock(&hv->hv_lock); +} + static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) { |