Userspace assumes that it can wire up IRQ injections after having created all VCPUs and after having created the VGIC, but potentially before starting the first VCPU. This can currently lead to lost IRQs because the state of that IRQ injection is not stored anywhere and we don't return an error to userspace.
We haven't seen this problem manifest itself yet, presumably because guests reset the devices on boot, but this could cause issues with migration and other non-standard startup configurations. Signed-off-by: Christoffer Dall <[email protected]> --- virt/kvm/arm/vgic.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index e1bef68..330445c 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1693,11 +1693,22 @@ out: int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, bool level) { - if (likely(vgic_ready(kvm)) && - vgic_update_irq_pending(kvm, cpuid, irq_num, level)) + int ret = 0; + + if (unlikely(!vgic_initialized(kvm))) { + mutex_lock(&kvm->lock); + ret = vgic_init(kvm); + mutex_unlock(&kvm->lock); + + if (ret) + goto out; + } + + if (vgic_update_irq_pending(kvm, cpuid, irq_num, level)) vgic_kick_vcpus(kvm); - return 0; +out: + return ret; } static irqreturn_t vgic_maintenance_handler(int irq, void *data) -- 2.1.2.330.g565301e.dirty -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
