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iommufd: Allow a hwpt to be aborted after allocation

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During creation the hwpt must have the ioas->mutex held until the object
is finalized. This means we need to be able to call
iommufd_object_abort_and_destroy() while holding the mutex.

Since iommufd_hw_pagetable_destroy() also needs the mutex this is
problematic.

Fix it by creating a special abort op for the object that can assume the
caller is holding the lock, as required by the contract.

The next patch will add another iommufd_object_abort_and_destroy() for a
hwpt.

Fixes: e8d5721003 ("iommufd: Add kAPI toward external drivers for physical devices")
Link: https://lore.kernel.org/r/10-v8-6659224517ea+532-iommufd_alloc_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe 2023-07-17 15:12:06 -03:00
parent 17bad52708
commit 70eadc7fc7
3 changed files with 26 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/iommu/iommufd/hw_pagetable.c
View File

@ -25,6 +25,21 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
refcount_dec(&hwpt->ioas->obj.users);
}
void iommufd_hw_pagetable_abort(struct iommufd_object *obj)
{
struct iommufd_hw_pagetable *hwpt =
container_of(obj, struct iommufd_hw_pagetable, obj);
/* The ioas->mutex must be held until finalize is called. */
lockdep_assert_held(&hwpt->ioas->mutex);
if (!list_empty(&hwpt->hwpt_item)) {
list_del_init(&hwpt->hwpt_item);
iopt_table_remove_domain(&hwpt->ioas->iopt, hwpt->domain);
}
iommufd_hw_pagetable_destroy(obj);
}
int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
{
if (hwpt->enforce_cache_coherency)
@ -49,6 +64,10 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
* Allocate a new iommu_domain and return it as a hw_pagetable. The HWPT
* will be linked to the given ioas and upon return the underlying iommu_domain
* is fully popoulated.
*
* The caller must hold the ioas->mutex until after
* iommufd_object_abort_and_destroy() or iommufd_object_finalize() is called on
* the returned hwpt.
*/
struct iommufd_hw_pagetable *
iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,

1
drivers/iommu/iommufd/iommufd_private.h
View File

@ -260,6 +260,7 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
struct iommufd_hw_pagetable *
iommufd_hw_pagetable_detach(struct iommufd_device *idev);
void iommufd_hw_pagetable_destroy(struct iommufd_object *obj);
void iommufd_hw_pagetable_abort(struct iommufd_object *obj);
static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx,
struct iommufd_hw_pagetable *hwpt)

7
drivers/iommu/iommufd/main.c
View File

@ -24,6 +24,7 @@
struct iommufd_object_ops {
void (*destroy)(struct iommufd_object *obj);
void (*abort)(struct iommufd_object *obj);
};
static const struct iommufd_object_ops iommufd_object_ops[];
static struct miscdevice vfio_misc_dev;
@ -95,7 +96,10 @@ void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj)
void iommufd_object_abort_and_destroy(struct iommufd_ctx *ictx,
struct iommufd_object *obj)
{
iommufd_object_ops[obj->type].destroy(obj);
if (iommufd_object_ops[obj->type].abort)
iommufd_object_ops[obj->type].abort(obj);
else
iommufd_object_ops[obj->type].destroy(obj);
iommufd_object_abort(ictx, obj);
}
@ -425,6 +429,7 @@ static const struct iommufd_object_ops iommufd_object_ops[] = {
},
[IOMMUFD_OBJ_HW_PAGETABLE] = {
.destroy = iommufd_hw_pagetable_destroy,
.abort = iommufd_hw_pagetable_abort,
},
#ifdef CONFIG_IOMMUFD_TEST
[IOMMUFD_OBJ_SELFTEST] = {