From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jim Mattson <jmattson@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Joerg Roedel <joro@8bytes.org>, kvm list <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Oliver Upton <oupton@google.com>, Peter Shier <pshier@google.com>
Subject: Re: [PATCH 12/13] KVM: x86: Replace late check_nested_events() hack with more precise fix
Date: Tue, 28 Apr 2020 15:20:10 -0700 [thread overview]
Message-ID: <20200428222010.GN12735@linux.intel.com> (raw)
In-Reply-To: <CALMp9eTiGdYPpejAOLNz7zzqP1wPXb_zSL02F27VMHeHGzANJg@mail.gmail.com>
On Tue, Apr 28, 2020 at 03:12:51PM -0700, Jim Mattson wrote:
> On Wed, Apr 22, 2020 at 7:26 PM Sean Christopherson
> <sean.j.christopherson@intel.com> wrote:
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 7c49a7dc601f..d9d6028a77e0 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -7755,24 +7755,10 @@ static int inject_pending_event(struct kvm_vcpu *vcpu)
> > --vcpu->arch.nmi_pending;
> > vcpu->arch.nmi_injected = true;
> > kvm_x86_ops.set_nmi(vcpu);
> > - } else if (kvm_cpu_has_injectable_intr(vcpu)) {
> > - /*
> > - * Because interrupts can be injected asynchronously, we are
> > - * calling check_nested_events again here to avoid a race condition.
> > - * See https://lkml.org/lkml/2014/7/2/60 for discussion about this
> > - * proposal and current concerns. Perhaps we should be setting
> > - * KVM_REQ_EVENT only on certain events and not unconditionally?
> > - */
> > - if (is_guest_mode(vcpu) && kvm_x86_ops.check_nested_events) {
> > - r = kvm_x86_ops.check_nested_events(vcpu);
> > - if (r != 0)
> > - return r;
> > - }
> > - if (kvm_x86_ops.interrupt_allowed(vcpu)) {
> > - kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu),
> > - false);
> > - kvm_x86_ops.set_irq(vcpu);
> > - }
> > + } else if (kvm_cpu_has_injectable_intr(vcpu) &&
> > + kvm_x86_ops.interrupt_injection_allowed(vcpu)) {
> > + kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu), false);
> > + kvm_x86_ops.set_irq(vcpu);
> > }
> So, that's what this mess was all about! Well, this certainly looks better.
Right? I can't count the number of times I've looked at this code and
wondered what the hell it was doing.
Side topic, I just realized you're reviewing my original series. Paolo
commandeered it to extend it to SVM. https://patchwork.kernel.org/cover/11508679/
next prev parent reply other threads:[~2020-04-28 22:20 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-23 2:25 [PATCH 00/13] KVM: x86: Event fixes and cleanup Sean Christopherson
2020-04-23 2:25 ` [PATCH 01/13] KVM: nVMX: Preserve exception priority irrespective of exiting behavior Sean Christopherson
2020-04-28 18:54 ` Jim Mattson
2020-04-28 20:07 ` Oliver Upton
2020-04-23 2:25 ` [PATCH 02/13] KVM: nVMX: Open a window for pending nested VMX preemption timer Sean Christopherson
2020-04-28 21:39 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 03/13] KVM: x86: Set KVM_REQ_EVENT if run is canceled with req_immediate_exit set Sean Christopherson
2020-04-28 21:41 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 04/13] KVM: x86: Make return for {interrupt_nmi}_allowed() a bool instead of int Sean Christopherson
2020-04-28 21:42 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 05/13] KVM: nVMX: Move nested_exit_on_nmi() to nested.h Sean Christopherson
2020-04-28 21:44 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 06/13] KVM: nVMX: Report NMIs as allowed when in L2 and Exit-on-NMI is set Sean Christopherson
2020-04-28 21:46 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 07/13] KVM: VMX: Split out architectural interrupt/NMI blocking checks Sean Christopherson
2020-04-28 21:57 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 08/13] KVM: nVMX: Preserve IRQ/NMI priority irrespective of exiting behavior Sean Christopherson
2020-04-28 21:58 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 09/13] KVM: nVMX: Prioritize SMI over nested IRQ/NMI Sean Christopherson
2020-04-28 22:04 ` Jim Mattson
2020-04-28 22:59 ` Sean Christopherson
2020-04-28 23:16 ` Jim Mattson
2020-04-29 14:50 ` Sean Christopherson
2020-04-29 20:06 ` Sean Christopherson
2020-04-28 23:23 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 10/13] KVM: x86: WARN on injected+pending exception even in nested case Sean Christopherson
2020-04-28 22:05 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 11/13] KVM: VMX: Use vmx_interrupt_blocked() directly from vmx_handle_exit() Sean Christopherson
2020-04-28 22:07 ` Jim Mattson
2020-04-23 2:25 ` [PATCH 12/13] KVM: x86: Replace late check_nested_events() hack with more precise fix Sean Christopherson
2020-04-23 11:00 ` Paolo Bonzini
2020-04-28 22:12 ` Jim Mattson
2020-04-28 22:20 ` Sean Christopherson [this message]
2020-04-29 8:36 ` Paolo Bonzini
2020-04-29 16:45 ` Sean Christopherson
2020-04-29 16:58 ` Paolo Bonzini
2020-04-29 17:07 ` Sean Christopherson
2020-04-23 2:25 ` [PATCH 13/13] KVM: VMX: Use vmx_get_rflags() to query RFLAGS in vmx_interrupt_blocked() Sean Christopherson
2020-04-28 22:13 ` Jim Mattson
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