Commit e719b4c8 authored by Marc Zyngier's avatar Marc Zyngier Committed by Luis Henriques

KVM: ARM: vgic: plug irq injection race

commit 71afaba4 upstream.

As it stands, nothing prevents userspace from injecting an interrupt
before the guest's GIC is actually initialized.

This goes unnoticed so far (as everything is pretty much statically
allocated), but ends up exploding in a spectacular way once we switch
to a more dynamic allocation (the GIC data structure isn't there yet).

The fix is to test for the "ready" flag in the VGIC distributor before
trying to inject the interrupt. Note that in order to avoid breaking
userspace, we have to ignore what is essentially an error.
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Acked-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarShannon Zhao <shannon.zhao@linaro.org>
[ luis: backported to 3.16: used shannon's backport to 3.14 ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 1992d9ec
......@@ -1387,7 +1387,8 @@ static bool vgic_update_irq_state(struct kvm *kvm, int cpuid,
int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
bool level)
{
if (vgic_update_irq_state(kvm, cpuid, irq_num, level))
if (likely(vgic_initialized(kvm)) &&
vgic_update_irq_state(kvm, cpuid, irq_num, level))
vgic_kick_vcpus(kvm);
return 0;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment