Messages in this thread | | | From | Paolo Bonzini <> | Subject | Re: [PATCH v2 1/4] KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES on nested vmexit | Date | Thu, 7 Jan 2021 18:59:59 +0100 |
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On 07/01/21 18:51, Paolo Bonzini wrote: > On 07/01/21 18:00, Sean Christopherson wrote: >> Ugh, I assume this is due to one of the "premature" >> nested_ops->check_events() >> calls that are necessitated by the event mess? I'm guessing >> kvm_vcpu_running() >> is the culprit? >> >> If my assumption is correct, this bug affects nVMX as well. > > Yes, though it may be latent. For SVM it was until we started > allocating svm->nested on demand. > >> Rather than clear the request blindly on any nested VM-Exit, what >> about something like the following? > > I think your patch is overkill, KVM_REQ_GET_NESTED_STATE_PAGES is only > set from KVM_SET_NESTED_STATE so it cannot happen while the VM runs.
... and when leaving SMM. But in either case, there cannot be something else causing a nested vmexit before the request is set, because SMM does not support VMX operation. So I still don't think that it justifies the extra code and indirection.
Paolo
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