Commit 127a457a authored by Matt Gingell's avatar Matt Gingell Committed by Paolo Bonzini
Browse files

KVM: x86: fix interrupt window handling in split IRQ chip case 



This patch ensures that dm_request_for_irq_injection and
post_kvm_run_save are in sync, avoiding that an endless ping-pong
between userspace (who correctly notices that IF=0) and
the kernel (who insists that userspace handles its request
for the interrupt window).

To synchronize them, it also adds checks for kvm_arch_interrupt_allowed
and !kvm_event_needs_reinjection.  These are always needed, not
just for in-kernel LAPIC.

Signed-off-by: default avatarMatt Gingell <gingell@google.com>
[A collage of two patches from Matt. - Paolo]
Fixes: 1c1a9ce9
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 585bb8f9

arch/x86/kvm/x86.c

+19 −14
Original line number Diff line number Diff line
@@ -2763,6 +2763,12 @@ static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu, 
	return 0;

}



static int kvm_cpu_accept_dm_intr(struct kvm_vcpu *vcpu)

{

	return (!lapic_in_kernel(vcpu) ||

		kvm_apic_accept_pic_intr(vcpu));

}



static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,

				    struct kvm_interrupt *irq)

{
@@ -5921,12 +5927,16 @@ static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu) 
	if (!vcpu->run->request_interrupt_window || pic_in_kernel(vcpu->kvm))

		return false;



	if (!kvm_arch_interrupt_allowed(vcpu))

		return false;



	if (kvm_cpu_has_interrupt(vcpu))

		return false;



	return (irqchip_split(vcpu->kvm)

		? kvm_apic_accept_pic_intr(vcpu)

		: kvm_arch_interrupt_allowed(vcpu));

	if (kvm_event_needs_reinjection(vcpu))

		return false;



	return kvm_cpu_accept_dm_intr(vcpu);

}



static void post_kvm_run_save(struct kvm_vcpu *vcpu)
@@ -5937,17 +5947,12 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu) 
	kvm_run->flags = is_smm(vcpu) ? KVM_RUN_X86_SMM : 0;

	kvm_run->cr8 = kvm_get_cr8(vcpu);

	kvm_run->apic_base = kvm_get_apic_base(vcpu);

	if (!irqchip_in_kernel(vcpu->kvm))

	kvm_run->ready_for_interrupt_injection =

			kvm_arch_interrupt_allowed(vcpu) &&

		pic_in_kernel(vcpu->kvm) ||

		(kvm_arch_interrupt_allowed(vcpu) &&

		 !kvm_cpu_has_interrupt(vcpu) &&

			!kvm_event_needs_reinjection(vcpu);

	else if (!pic_in_kernel(vcpu->kvm))

		kvm_run->ready_for_interrupt_injection =

			kvm_apic_accept_pic_intr(vcpu) &&

			!kvm_cpu_has_interrupt(vcpu);

	else

		kvm_run->ready_for_interrupt_injection = 1;

		 !kvm_event_needs_reinjection(vcpu) &&

		 kvm_cpu_accept_dm_intr(vcpu));

}



static void update_cr8_intercept(struct kvm_vcpu *vcpu)

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