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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: Mark McLoughlin <markmc@redhat.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Mark McLoughlin 2009-02-05 18:23:46 +00:00 committed by Avi Kivity
parent b682b814e3
commit 682edb4c01
2 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
virt/kvm/iommu.c
View File

@ -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;
}

3
virt/kvm/kvm_main.c
View File

@ -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