Commit 831b40f8 authored by Yi Liu's avatar Yi Liu Committed by Jason Gunthorpe
Browse files

iommufd/device: Replace device_list with device_array 

igroup->attach->device_list is used to track attached device of a group
in the RID path. Such tracking is also needed in the PASID path in order
to share path with the RID path.

While there is only one list_head in the iommufd_device. It cannot work
if the device has been attached in both RID path and PASID path. To solve
it, replacing the device_list with an xarray. The attached iommufd_device
is stored in the entry indexed by the idev->obj.id.

Link: https://patch.msgid.link/r/20250321171940.7213-9-yi.l.liu@intel.com


Reviewed-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarYi Liu <yi.l.liu@intel.com>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 75f990ae

drivers/iommu/iommufd/device.c

+39 −19
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ MODULE_PARM_DESC( 


struct iommufd_attach {

	struct iommufd_hw_pagetable *hwpt;

	struct list_head device_list;

	struct xarray device_array;

};



static void iommufd_group_release(struct kref *kref)
@@ -297,6 +297,20 @@ u32 iommufd_device_to_id(struct iommufd_device *idev) 
}

EXPORT_SYMBOL_NS_GPL(iommufd_device_to_id, "IOMMUFD");



static unsigned int iommufd_group_device_num(struct iommufd_group *igroup)

{

	struct iommufd_device *idev;

	unsigned int count = 0;

	unsigned long index;



	lockdep_assert_held(&igroup->lock);



	if (igroup->attach)

		xa_for_each(&igroup->attach->device_array, index, idev)

			count++;

	return count;

}



#ifdef CONFIG_IRQ_MSI_IOMMU

static int iommufd_group_setup_msi(struct iommufd_group *igroup,

				   struct iommufd_hwpt_paging *hwpt_paging)
@@ -371,12 +385,7 @@ iommufd_device_attach_reserved_iova(struct iommufd_device *idev, 
/* Check if idev is attached to igroup->hwpt */

static bool iommufd_device_is_attached(struct iommufd_device *idev)

{

	struct iommufd_device *cur;



	list_for_each_entry(cur, &idev->igroup->attach->device_list, group_item)

		if (cur == idev)

			return true;

	return false;

	return xa_load(&idev->igroup->attach->device_array, idev->obj.id);

}



static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
@@ -510,20 +519,27 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, 
			rc = -ENOMEM;

			goto err_unlock;

		}

		INIT_LIST_HEAD(&attach->device_list);

		xa_init(&attach->device_array);

	}



	old_hwpt = attach->hwpt;



	rc = xa_insert(&attach->device_array, idev->obj.id, XA_ZERO_ENTRY,

		       GFP_KERNEL);

	if (rc) {

		WARN_ON(rc == -EBUSY && !old_hwpt);

		goto err_free_attach;

	}



	if (old_hwpt && old_hwpt != hwpt) {

		rc = -EINVAL;

		goto err_free_attach;

		goto err_release_devid;

	}



	if (attach_resv) {

		rc = iommufd_device_attach_reserved_iova(idev, hwpt_paging);

		if (rc)

			goto err_free_attach;

			goto err_release_devid;

	}



	/*
@@ -541,12 +557,15 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, 
		igroup->attach = attach;

	}

	refcount_inc(&hwpt->obj.users);

	list_add_tail(&idev->group_item, &attach->device_list);

	WARN_ON(xa_is_err(xa_store(&attach->device_array, idev->obj.id,

				   idev, GFP_KERNEL)));

	mutex_unlock(&igroup->lock);

	return 0;

err_unresv:

	if (attach_resv)

		iopt_remove_reserved_iova(&hwpt_paging->ioas->iopt, idev->dev);

err_release_devid:

	xa_release(&attach->device_array, idev->obj.id);

err_free_attach:

	if (iommufd_group_first_attach(igroup, pasid))

		kfree(attach);
@@ -568,8 +587,8 @@ iommufd_hw_pagetable_detach(struct iommufd_device *idev, ioasid_t pasid) 
	hwpt = attach->hwpt;

	hwpt_paging = find_hwpt_paging(hwpt);



	list_del(&idev->group_item);

	if (list_empty(&attach->device_list)) {

	xa_erase(&attach->device_array, idev->obj.id);

	if (xa_empty(&attach->device_array)) {

		iommufd_hwpt_detach_device(hwpt, idev, pasid);

		igroup->attach = NULL;

		kfree(attach);
@@ -599,10 +618,11 @@ iommufd_group_remove_reserved_iova(struct iommufd_group *igroup, 
				   struct iommufd_hwpt_paging *hwpt_paging)

{

	struct iommufd_device *cur;

	unsigned long index;



	lockdep_assert_held(&igroup->lock);



	list_for_each_entry(cur, &igroup->attach->device_list, group_item)

	xa_for_each(&igroup->attach->device_array, index, cur)

		iopt_remove_reserved_iova(&hwpt_paging->ioas->iopt, cur->dev);

}
@@ -612,14 +632,14 @@ iommufd_group_do_replace_reserved_iova(struct iommufd_group *igroup, 
{

	struct iommufd_hwpt_paging *old_hwpt_paging;

	struct iommufd_device *cur;

	unsigned long index;

	int rc;



	lockdep_assert_held(&igroup->lock);



	old_hwpt_paging = find_hwpt_paging(igroup->attach->hwpt);

	if (!old_hwpt_paging || hwpt_paging->ioas != old_hwpt_paging->ioas) {

		list_for_each_entry(cur,

				    &igroup->attach->device_list, group_item) {

		xa_for_each(&igroup->attach->device_array, index, cur) {

			rc = iopt_table_enforce_dev_resv_regions(

				&hwpt_paging->ioas->iopt, cur->dev, NULL);

			if (rc)
@@ -660,7 +680,7 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid, 


	old_hwpt = attach->hwpt;



	WARN_ON(!old_hwpt || list_empty(&attach->device_list));

	WARN_ON(!old_hwpt || xa_empty(&attach->device_array));



	if (!iommufd_device_is_attached(idev)) {

		rc = -EINVAL;
@@ -689,9 +709,9 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid, 


	attach->hwpt = hwpt;



	num_devices = list_count_nodes(&attach->device_list);

	num_devices = iommufd_group_device_num(igroup);

	/*

	 * Move the refcounts held by the device_list to the new hwpt. Retain a

	 * Move the refcounts held by the device_array to the new hwpt. Retain a

	 * refcount for this thread as the caller will free it.

	 */

	refcount_add(num_devices, &hwpt->obj.users);