The patch below does not apply to the 4.3-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 127a457acb2131fdb31c68c98cf11eda8ba7b380 Mon Sep 17 00:00:00 2001
From: Matt Gingell <gingell@xxxxxxxxxx>
Date: Tue, 17 Nov 2015 17:32:05 +0100
Subject: [PATCH] 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: Matt Gingell <gingell@xxxxxxxxxx>
[A collage of two patches from Matt. - Paolo]
Fixes: 1c1a9ce973a7863dd46767226bce2a5f12d48bc6
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 00462bd63129..46ed8edad793 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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)
--
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