The access object has been used externally by VFIO mdev devices, allowing
them to pin/unpin physical pages (via needs_pin_pages). Meanwhile, a racy
unmap can occur in this case, so these devices usually implement an unmap
handler, invoked by iommufd_access_notify_unmap().
The new HW queue object will need the same pin/unpin feature, although it
(unlike the mdev case) wants to reject any unmap attempt, during its life
cycle. Instead, it would not implement an unmap handler. Thus, bypass any
access->ops->unmap access call when the access is marked as internal.
Also, an area being pinned by an internal access should reject any unmap
request. This cannot be done inside iommufd_access_notify_unmap() as it's
a per-iopt action. Add a "num_locks" counter in the struct iopt_area, set
that in iopt_area_add_access() when the caller is an internal access.
Link: https://patch.msgid.link/r/6df9a43febf79c0379091ec59747276ce9d2493b.1752126748.git.nicolinc@nvidia.com
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
}
if (cur_ioas) {
- if (access->ops->unmap) {
+ if (!iommufd_access_is_internal(access) && access->ops->unmap) {
mutex_unlock(&access->ioas_lock);
access->ops->unmap(access->data, 0, ULONG_MAX);
mutex_lock(&access->ioas_lock);
xa_lock(&ioas->iopt.access_list);
xa_for_each(&ioas->iopt.access_list, index, access) {
- if (!iommufd_lock_obj(&access->obj))
+ if (!iommufd_lock_obj(&access->obj) ||
+ iommufd_access_is_internal(access))
continue;
xa_unlock(&ioas->iopt.access_list);
void iommufd_access_unpin_pages(struct iommufd_access *access,
unsigned long iova, unsigned long length)
{
+ bool internal = iommufd_access_is_internal(access);
struct iopt_area_contig_iter iter;
struct io_pagetable *iopt;
unsigned long last_iova;
area, iopt_area_iova_to_index(area, iter.cur_iova),
iopt_area_iova_to_index(
area,
- min(last_iova, iopt_area_last_iova(area))));
+ min(last_iova, iopt_area_last_iova(area))),
+ internal);
WARN_ON(!iopt_area_contig_done(&iter));
up_read(&iopt->iova_rwsem);
mutex_unlock(&access->ioas_lock);
unsigned long length, struct page **out_pages,
unsigned int flags)
{
+ bool internal = iommufd_access_is_internal(access);
struct iopt_area_contig_iter iter;
struct io_pagetable *iopt;
unsigned long last_iova;
/* Driver's ops don't support pin_pages */
if (IS_ENABLED(CONFIG_IOMMUFD_TEST) &&
- WARN_ON(access->iova_alignment != PAGE_SIZE || !access->ops->unmap))
+ WARN_ON(access->iova_alignment != PAGE_SIZE ||
+ (!internal && !access->ops->unmap)))
return -EINVAL;
if (!length)
}
rc = iopt_area_add_access(area, index, last_index, out_pages,
- flags);
+ flags, internal);
if (rc)
goto err_remove;
out_pages += last_index - index + 1;
iopt_area_iova_to_index(area, iter.cur_iova),
iopt_area_iova_to_index(
area, min(last_iova,
- iopt_area_last_iova(area))));
+ iopt_area_last_iova(area))),
+ internal);
}
up_read(&iopt->iova_rwsem);
mutex_unlock(&access->ioas_lock);
goto out_unlock_iova;
}
+ /* The area is locked by an object that has not been destroyed */
+ if (area->num_locks) {
+ rc = -EBUSY;
+ goto out_unlock_iova;
+ }
+
if (area_first < start || area_last > last) {
rc = -ENOENT;
goto out_unlock_iova;
int iommu_prot;
bool prevent_access : 1;
unsigned int num_accesses;
+ unsigned int num_locks;
};
struct iopt_allowed {
int iopt_area_add_access(struct iopt_area *area, unsigned long start,
unsigned long last, struct page **out_pages,
- unsigned int flags);
+ unsigned int flags, bool lock_area);
void iopt_area_remove_access(struct iopt_area *area, unsigned long start,
- unsigned long last);
+ unsigned long last, bool unlock_area);
int iopt_pages_rw_access(struct iopt_pages *pages, unsigned long start_byte,
void *data, unsigned long length, unsigned int flags);
* @last_index: Inclusive last page index
* @out_pages: Output list of struct page's representing the PFNs
* @flags: IOMMUFD_ACCESS_RW_* flags
+ * @lock_area: Fail userspace munmap on this area
*
* Record that an in-kernel access will be accessing the pages, ensure they are
* pinned, and return the PFNs as a simple list of 'struct page *'.
*/
int iopt_area_add_access(struct iopt_area *area, unsigned long start_index,
unsigned long last_index, struct page **out_pages,
- unsigned int flags)
+ unsigned int flags, bool lock_area)
{
struct iopt_pages *pages = area->pages;
struct iopt_pages_access *access;
access = iopt_pages_get_exact_access(pages, start_index, last_index);
if (access) {
area->num_accesses++;
+ if (lock_area)
+ area->num_locks++;
access->users++;
iopt_pages_fill_from_xarray(pages, start_index, last_index,
out_pages);
access->node.last = last_index;
access->users = 1;
area->num_accesses++;
+ if (lock_area)
+ area->num_locks++;
interval_tree_insert(&access->node, &pages->access_itree);
mutex_unlock(&pages->mutex);
return 0;
* @area: The source of PFNs
* @start_index: First page index
* @last_index: Inclusive last page index
+ * @unlock_area: Must match the matching iopt_area_add_access()'s lock_area
*
* Undo iopt_area_add_access() and unpin the pages if necessary. The caller
* must stop using the PFNs before calling this.
*/
void iopt_area_remove_access(struct iopt_area *area, unsigned long start_index,
- unsigned long last_index)
+ unsigned long last_index, bool unlock_area)
{
struct iopt_pages *pages = area->pages;
struct iopt_pages_access *access;
goto out_unlock;
WARN_ON(area->num_accesses == 0 || access->users == 0);
+ if (unlock_area) {
+ WARN_ON(area->num_locks == 0);
+ area->num_locks--;
+ }
area->num_accesses--;
access->users--;
if (access->users)
projects / thirdparty / kernel / linux.git / commitdiff
