On Wed, Mar 22, 2023, Vitaly Kuznetsov wrote:
Sean Christopherson seanjc@google.com writes:
diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h index cff838f15db5..d91e019fb7da 100644 --- a/arch/x86/kvm/svm/svm_onhyperv.h +++ b/arch/x86/kvm/svm/svm_onhyperv.h @@ -15,6 +15,13 @@ static struct kvm_x86_ops svm_x86_ops; int svm_hv_enable_l2_tlb_flush(struct kvm_vcpu *vcpu); +static inline bool svm_hv_is_enlightened_tlb_enabled(struct kvm_vcpu *vcpu) +{
- struct hv_vmcb_enlightenments *hve = &to_svm(vcpu)->vmcb->control.hv_enlightenments;
- return !!hve->hv_enlightenments_control.enlightened_npt_tlb;
In theory, we should not look at Hyper-V enlightenments in VMCB control just because our kernel has CONFIG_HYPERV enabled.
Oooh, right, because hv_enlightenments uses software reserved bits, and in theory KVM could be running on a different hypervisor that uses those bits for something completely different.
I'd suggest we add a real check that we're running on Hyper-V and we can do it the same way it is done in svm_hv_hardware_setup()/svm_hv_init_vmcb():
return (ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) && !!hve->hv_enlightenments_control.enlightened_npt_tlb;
Jeremi, if you grab this, can you put the && on the previous line? I.e.
return (ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) && !!hve->hv_enlightenments_control.enlightened_npt_tlb;