Commit 9ffc6fc6 authored by Alex Williamson's avatar Alex Williamson Committed by Greg Kroah-Hartman

vfio: New external user group/file match

commit 5d6dee80 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: default avatarAlex Williamson <alex.williamson@redhat.com>
Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Tested-by: default avatarEric Auger <eric.auger@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4fb3d76f
......@@ -1776,6 +1776,15 @@ 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);
......
......@@ -97,6 +97,8 @@ 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);
......
......@@ -51,6 +51,22 @@ 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 *);
......@@ -231,18 +247,13 @@ 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);
......@@ -260,7 +271,7 @@ 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);
......
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