diff options
| author | Alex Williamson <alex.williamson@redhat.com> | 2017-06-28 13:50:05 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-27 15:06:07 -0700 |
| commit | 3457c0459496d028a4f47167a8b8871671abdeda (patch) | |
| tree | be46c9476658460252f2f266d5fe5ab1de847d7e | |
| parent | db42944cc63a2db5de17b6cb572327c7ab8ab637 (diff) | |
vfio: New external user group/file match
commit 5d6dee80a1e94cc284d03e06d930e60e8d3ecf7d 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>
| -rw-r--r-- | drivers/vfio/vfio.c | 9 | ||||
| -rw-r--r-- | include/linux/vfio.h | 2 | ||||
| -rw-r--r-- | virt/kvm/vfio.c | 27 |
3 files changed, 30 insertions, 8 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 402d54f963e4..1e01e28f40f3 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1587,6 +1587,15 @@ void vfio_group_put_external_user(struct vfio_group *group) } EXPORT_SYMBOL_GPL(vfio_group_put_external_user); +bool vfio_external_group_match_file(struct vfio_group *test_group, + struct file *filep) +{ + struct vfio_group *group = filep->private_data; + + return (filep->f_op == &vfio_group_fops) && (group == test_group); +} +EXPORT_SYMBOL_GPL(vfio_external_group_match_file); + int vfio_external_user_iommu_id(struct vfio_group *group) { return iommu_group_id(group->iommu_group); diff --git a/include/linux/vfio.h b/include/linux/vfio.h index ddb440975382..34851bf2e2c8 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -85,6 +85,8 @@ extern void vfio_unregister_iommu_driver( */ extern struct vfio_group *vfio_group_get_external_user(struct file *filep); extern void vfio_group_put_external_user(struct vfio_group *group); +extern bool vfio_external_group_match_file(struct vfio_group *group, + struct file *filep); extern int vfio_external_user_iommu_id(struct vfio_group *group); extern long vfio_external_check_extension(struct vfio_group *group, unsigned long arg); diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c index 1dd087da6f31..111e09c3f4bf 100644 --- a/virt/kvm/vfio.c +++ b/virt/kvm/vfio.c @@ -47,6 +47,22 @@ static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep) return vfio_group; } +static bool kvm_vfio_external_group_match_file(struct vfio_group *group, + struct file *filep) +{ + bool ret, (*fn)(struct vfio_group *, struct file *); + + fn = symbol_get(vfio_external_group_match_file); + if (!fn) + return false; + + ret = fn(group, filep); + + symbol_put(vfio_external_group_match_file); + + return ret; +} + static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group) { void (*fn)(struct vfio_group *); @@ -171,18 +187,13 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) if (!f.file) return -EBADF; - vfio_group = kvm_vfio_group_get_external_user(f.file); - fdput(f); - - if (IS_ERR(vfio_group)) - return PTR_ERR(vfio_group); - ret = -ENOENT; mutex_lock(&kv->lock); list_for_each_entry(kvg, &kv->group_list, node) { - if (kvg->vfio_group != vfio_group) + if (!kvm_vfio_external_group_match_file(kvg->vfio_group, + f.file)) continue; list_del(&kvg->node); @@ -196,7 +207,7 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg) mutex_unlock(&kv->lock); - kvm_vfio_group_put_external_user(vfio_group); + fdput(f); kvm_vfio_update_coherency(dev); |