Avoid races between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP by taking the kvm->lock when setting up routes. If KVM_CREATE_IRQCHIP fails, KVM_SET_GSI_ROUTING could have already set up routes pointing at pic/ioapic, being silently removed already. Also, as a side effect, this patch makes sure that KVM_SET_GSI_ROUTING and KVM_CAP_SPLIT_IRQCHIP cannot run in parallel. Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> --- virt/kvm/kvm_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 88257b3..a80e400 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3082,8 +3082,11 @@ static long kvm_vm_ioctl(struct file *filp, routing.nr * sizeof(*entries))) goto out_free_irq_routing; } + /* avoid races with KVM_CREATE_IRQCHIP on x86 */ + mutex_lock(&kvm->lock); r = kvm_set_irq_routing(kvm, entries, routing.nr, routing.flags); + mutex_unlock(&kvm->lock); out_free_irq_routing: vfree(entries); break; -- 2.9.3
