From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v2 3/3] KVM: Non-atomic interrupt injection
Date: Wed, 21 Jul 2010 13:27:00 -0300
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 <20100721005533.GA9989@amt.cnet>
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Cc: kvm@vger.kernel.org
To: Avi Kivity <avi@redhat.com>
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On Wed, Jul 21, 2010 at 08:37:26AM +0300, Avi Kivity wrote:
> On 07/21/2010 03:55 AM, Marcelo Tosatti wrote:
> >
> >>--- a/arch/x86/kvm/x86.c
> >>+++ b/arch/x86/kvm/x86.c
> >>@@ -4709,6 +4709,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> >>  	if (unlikely(r))
> >>  		goto out;
> >>
> >>+	inject_pending_event(vcpu);
> >>+
> >>+	/* enable NMI/IRQ window open exits if needed */
> >>+	if (vcpu->arch.nmi_pending)
> >>+		kvm_x86_ops->enable_nmi_window(vcpu);
> >>+	else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> >>+		kvm_x86_ops->enable_irq_window(vcpu);
> >>+
> >>+	if (kvm_lapic_enabled(vcpu)) {
> >>+		update_cr8_intercept(vcpu);
> >>+		kvm_lapic_sync_to_vapic(vcpu);
> >>+	}
> >>+
> >>  	preempt_disable();
> >>
> >>  	kvm_x86_ops->prepare_guest_switch(vcpu);
> >>@@ -4727,23 +4740,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> >>  		smp_wmb();
> >>  		local_irq_enable();
> >>  		preempt_enable();
> >>+		kvm_x86_ops->cancel_injection(vcpu);
> >>  		r = 1;
> >>  		goto out;
> >>  	}
> >>
> >>-	inject_pending_event(vcpu);
> >>-
> >>-	/* enable NMI/IRQ window open exits if needed */
> >>-	if (vcpu->arch.nmi_pending)
> >>-		kvm_x86_ops->enable_nmi_window(vcpu);
> >>-	else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> >>-		kvm_x86_ops->enable_irq_window(vcpu);
> >>-
> >>-	if (kvm_lapic_enabled(vcpu)) {
> >>-		update_cr8_intercept(vcpu);
> >>-		kvm_lapic_sync_to_vapic(vcpu);
> >>-	}
> >>-
> >>  	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
> >>
> >>  	kvm_guest_enter();
> >This breaks
> >
> >int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
> >{
> >         struct kvm_lapic *apic = vcpu->arch.apic;
> >         int highest_irr;
> >
> >         /* This may race with setting of irr in __apic_accept_irq() and
> >          * value returned may be wrong, but kvm_vcpu_kick() in
> >          * __apic_accept_irq
> >          * will cause vmexit immediately and the value will be
> >          * recalculated
> >          * on the next vmentry.
> >          */
> >
> >(also valid for nmi_pending and PIC). Can't simply move
> >atomic_set(guest_mode, 1) in preemptible section as that would make it
> >possible for kvm_vcpu_kick to IPI stale vcpu->cpu.
> 
> Right.  Can fix by adding a kvm_make_request() to force the retry loop.
> 
> >Also should undo vmx.rmode.* ?
> 
> Elaborate?

Undo vmx.rmode assignments on cancel_injection.