From 1df6ddede10a1cacbf1da4cdfca3342510db1882 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 7 Apr 2017 10:50:18 +0200 Subject: [PATCH] KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Radim Krčmář --- 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 f489167839c4..357e67cba32e 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3069,8 +3069,11 @@ 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;