vfio: New external user group/file match
commit 5d6dee80a1
upstream.
At the point where the kvm-vfio pseudo device wants to release its
vfio group reference, we can't always acquire a new reference to make
that happen. The group can be in a state where we wouldn't allow a
new reference to be added. This new helper function allows a caller
to match a file to a group to facilitate this. Given a file and
group, report if they match. Thus the caller needs to already have a
group reference to match to the file. This allows the deletion of a
group without acquiring a new reference.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
master
parent
e91a55790d
commit
8f9dec0c2d
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@ -1751,6 +1751,15 @@ void vfio_group_put_external_user(struct vfio_group *group)
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}
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EXPORT_SYMBOL_GPL(vfio_group_put_external_user);
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bool vfio_external_group_match_file(struct vfio_group *test_group,
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struct file *filep)
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{
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struct vfio_group *group = filep->private_data;
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return (filep->f_op == &vfio_group_fops) && (group == test_group);
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}
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EXPORT_SYMBOL_GPL(vfio_external_group_match_file);
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int vfio_external_user_iommu_id(struct vfio_group *group)
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{
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return iommu_group_id(group->iommu_group);
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@ -88,6 +88,8 @@ extern void vfio_unregister_iommu_driver(
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*/
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extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
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extern void vfio_group_put_external_user(struct vfio_group *group);
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extern bool vfio_external_group_match_file(struct vfio_group *group,
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struct file *filep);
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extern int vfio_external_user_iommu_id(struct vfio_group *group);
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extern long vfio_external_check_extension(struct vfio_group *group,
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unsigned long arg);
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@ -47,6 +47,22 @@ static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep)
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return vfio_group;
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}
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static bool kvm_vfio_external_group_match_file(struct vfio_group *group,
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struct file *filep)
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{
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bool ret, (*fn)(struct vfio_group *, struct file *);
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fn = symbol_get(vfio_external_group_match_file);
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if (!fn)
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return false;
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ret = fn(group, filep);
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symbol_put(vfio_external_group_match_file);
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return ret;
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}
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static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
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{
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void (*fn)(struct vfio_group *);
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@ -171,18 +187,13 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
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if (!f.file)
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return -EBADF;
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vfio_group = kvm_vfio_group_get_external_user(f.file);
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fdput(f);
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if (IS_ERR(vfio_group))
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return PTR_ERR(vfio_group);
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ret = -ENOENT;
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mutex_lock(&kv->lock);
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list_for_each_entry(kvg, &kv->group_list, node) {
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if (kvg->vfio_group != vfio_group)
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if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
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f.file))
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continue;
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list_del(&kvg->node);
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@ -196,7 +207,7 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
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mutex_unlock(&kv->lock);
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kvm_vfio_group_put_external_user(vfio_group);
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fdput(f);
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kvm_vfio_update_coherency(dev);
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