linux-kernel - Re: [PATCH 1/5] KVM: x86: Get vmcs12 pages before checking pending interrupts

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Date:   Wed, 3 Aug 2022 10:51:25 -0700
From:   Mingwei Zhang <mizhang@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm <kvm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Oliver Upton <oupton@...gle.com>
Subject: Re: [PATCH 1/5] KVM: x86: Get vmcs12 pages before checking pending interrupts

On Wed, Aug 3, 2022 at 10:18 AM Paolo Bonzini <pbonzini@...hat.com> wrote:
>
> On 8/3/22 01:07, Mingwei Zhang wrote:
> > +     /*
> > +      * We must first get the vmcs12 pages before checking for interrupts
> > +      * that might unblock the guest if L1 is using virtual-interrupt
> > +      * delivery.
> > +      */
> > +     if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu)) {
> > +             /*
> > +              * If we have to ask user-space to post-copy a page,
> > +              * then we have to keep trying to get all of the
> > +              * VMCS12 pages until we succeed.
> > +              */
> > +             if (unlikely(!kvm_x86_ops.nested_ops->get_nested_state_pages(vcpu))) {
> > +                     kvm_make_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
> > +                     return 0;
> > +             }
> > +     }
> > +
>
> I think request handling (except for KVM_REQ_EVENT) could be more
> generically moved from vcpu_enter_guest() to vcpu_run().

Yeah, sounds good to me. I can come up with an updated version. At
least, I will remove the repeat request here.

>
> Paolo
>