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KVM: x86: properly update ready_for_interrupt_injection

PATCH Applied Marcelo Tosatti 2 participants 2 messages May 4, 2010

Subsystems (3)
x86 KVM KVM x86
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Marcelo Tosatti

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#0 lore raw

The recent changes to emulate string instructions without entering guest mode exposed a bug where pending interrupts are not properly reflected in ready_for_interrupt_injection.

The result is that userspace overwrites a previously queued interrupt, when irqchip's are emulated in qemu.

Fix by always updating state before returning to userspace.

Signed-off-by Marcelo Tosatti <[email protected]>
arch/x86/kvm/x86.c +1 -1
index 6b2ce1d..dff08e5 100644
@@ -4653,7 +4653,6 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
 	}
 
 	srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
-	post_kvm_run_save(vcpu);
 
 	vapic_exit(vcpu);
 

@@ -4703,6 +4702,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	r = __vcpu_run(vcpu);
 
 out:
+	post_kvm_run_save(vcpu);
 	if (vcpu->sigset_active)
 		sigprocmask(SIG_SETMASK, &sigsaved, NULL);
Applied
#1 lore raw
Quoted 8 lines · Marcelo Tosatti

The recent changes to emulate string instructions without entering guest mode exposed a bug where pending interrupts are not properly reflected in ready_for_interrupt_injection.

The result is that userspace overwrites a previously queued interrupt, when irqchip's are emulated in qemu.

Applied, thanks.

Quoted 2 lines

Fix by always updating state before returning to userspace.

Why are we even doing this if irqchip_in_kernel?

Signature · 1 line
error compiling committee.c: too many arguments to function