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

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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: Matt Gingell <gingell@google.com>
[A collage of two patches from Matt. - Paolo]
Fixes: 1c1a9ce973
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Matt Gingell 2015-11-17 17:32:05 +01:00 committed by Paolo Bonzini
parent 585bb8f9a5
commit 127a457acb
1 changed files with 19 additions and 14 deletions
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33
arch/x86/kvm/x86.c
View file

@ -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) &&
!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_run->ready_for_interrupt_injection =
pic_in_kernel(vcpu->kvm) ||
(kvm_arch_interrupt_allowed(vcpu) &&
!kvm_cpu_has_interrupt(vcpu) &&
!kvm_event_needs_reinjection(vcpu) &&
kvm_cpu_accept_dm_intr(vcpu));
}
static void update_cr8_intercept(struct kvm_vcpu *vcpu)