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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>
This commit is contained in:
David Hildenbrand 2017-04-07 10:50:18 +02:00 committed by Radim Krčmář
parent f7b1a77d3b
commit 1df6ddede1
1 changed files with 3 additions and 0 deletions
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3
virt/kvm/kvm_main.c
View File

@ -3069,8 +3069,11 @@ static long kvm_vm_ioctl(struct file *filp,
routing.nr * sizeof(*entries))) routing.nr * sizeof(*entries)))
goto out_free_irq_routing; 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, r = kvm_set_irq_routing(kvm, entries, routing.nr,
routing.flags); routing.flags);
mutex_unlock(&kvm->lock);
out_free_irq_routing: out_free_irq_routing:
vfree(entries); vfree(entries);
break; break;