[PATCH v1 01/22] KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP

David Hildenbrand
2017-03-14T13:34:55Z

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.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
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 a17d787..ad0f8b2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3079,8 +3079,11 @@ 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