Commit 70eadc7f authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

iommufd: Allow a hwpt to be aborted after allocation 

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: e8d57210 ("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: default avatarKevin Tian <kevin.tian@intel.com>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 17bad527

drivers/iommu/iommufd/hw_pagetable.c

+19 −0
Original line number Diff line number Diff line
@@ -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,

drivers/iommu/iommufd/iommufd_private.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

drivers/iommu/iommufd/main.c

+6 −1
Original line number Diff line number Diff line
@@ -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;
@@ -95,6 +96,9 @@ 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)

{

	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] = {