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Commit 682edb4c authored by Mark McLoughlin's avatar Mark McLoughlin Committed by Avi Kivity
Browse files

KVM: Fix assigned devices circular locking dependency 



kvm->slots_lock is outer to kvm->lock, so take slots_lock
in kvm_vm_ioctl_assign_device() before taking kvm->lock,
rather than taking it in kvm_iommu_map_memslots().

Cc: stable@kernel.org
Signed-off-by: default avatarMark McLoughlin <markmc@redhat.com>
Acked-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent b682b814

virt/kvm/iommu.c

+2 −4
Original line number Diff line number Diff line
@@ -73,14 +73,13 @@ static int kvm_iommu_map_memslots(struct kvm *kvm) 
{

	int i, r = 0;



	down_read(&kvm->slots_lock);

	for (i = 0; i < kvm->nmemslots; i++) {

		r = kvm_iommu_map_pages(kvm, kvm->memslots[i].base_gfn,

					kvm->memslots[i].npages);

		if (r)

			break;

	}

	up_read(&kvm->slots_lock);



	return r;

}
@@ -190,12 +189,11 @@ static void kvm_iommu_put_pages(struct kvm *kvm, 
static int kvm_iommu_unmap_memslots(struct kvm *kvm)

{

	int i;

	down_read(&kvm->slots_lock);



	for (i = 0; i < kvm->nmemslots; i++) {

		kvm_iommu_put_pages(kvm, kvm->memslots[i].base_gfn,

				    kvm->memslots[i].npages);

	}

	up_read(&kvm->slots_lock);



	return 0;

}

virt/kvm/kvm_main.c

+3 −0
Original line number Diff line number Diff line
@@ -466,6 +466,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm, 
	struct kvm_assigned_dev_kernel *match;

	struct pci_dev *dev;



	down_read(&kvm->slots_lock);

	mutex_lock(&kvm->lock);



	match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
@@ -527,6 +528,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm, 


out:

	mutex_unlock(&kvm->lock);

	up_read(&kvm->slots_lock);

	return r;

out_list_del:

	list_del(&match->list);
@@ -538,6 +540,7 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm, 
out_free:

	kfree(match);

	mutex_unlock(&kvm->lock);

	up_read(&kvm->slots_lock);

	return r;

}

#endif