Commit 1df6dded authored Apr 07, 2017 by David Hildenbrand Committed by Radim Krčmář Apr 12, 2017

KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP



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@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

parent f7b1a77d

virt/kvm/kvm_main.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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;

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