Commit 75f990ae authored by Yi Liu's avatar Yi Liu Committed by Jason Gunthorpe
Browse files

iommufd/device: Wrap igroup->hwpt and igroup->device_list into attach struct 

The igroup->hwpt and igroup->device_list are used to track the hwpt attach
of a group in the RID path. While the coming PASID path also needs such
tracking. To be prepared, wrap igroup->hwpt and igroup->device_list into
attach struct which is allocated per attaching the first device of the
group and freed per detaching the last device of the group.

Link: https://patch.msgid.link/r/20250321171940.7213-8-yi.l.liu@intel.com


Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarNicolin Chen <nicolinc@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 ba1de6cd

drivers/iommu/iommufd/device.c

+55 −21
Original line number Diff line number Diff line
@@ -17,12 +17,17 @@ MODULE_PARM_DESC( 
	"Allow IOMMUFD to bind to devices even if the platform cannot isolate "

	"the MSI interrupt window. Enabling this is a security weakness.");



struct iommufd_attach {

	struct iommufd_hw_pagetable *hwpt;

	struct list_head device_list;

};



static void iommufd_group_release(struct kref *kref)

{

	struct iommufd_group *igroup =

		container_of(kref, struct iommufd_group, ref);



	WARN_ON(igroup->hwpt || !list_empty(&igroup->device_list));

	WARN_ON(igroup->attach);



	xa_cmpxchg(&igroup->ictx->groups, iommu_group_id(igroup->group), igroup,

		   NULL, GFP_KERNEL);
@@ -89,7 +94,6 @@ static struct iommufd_group *iommufd_get_group(struct iommufd_ctx *ictx, 


	kref_init(&new_igroup->ref);

	mutex_init(&new_igroup->lock);

	INIT_LIST_HEAD(&new_igroup->device_list);

	new_igroup->sw_msi_start = PHYS_ADDR_MAX;

	/* group reference moves into new_igroup */

	new_igroup->group = group;
@@ -333,7 +337,7 @@ static bool 
iommufd_group_first_attach(struct iommufd_group *igroup, ioasid_t pasid)

{

	lockdep_assert_held(&igroup->lock);

	return !igroup->hwpt;

	return !igroup->attach;

}



static int
@@ -369,7 +373,7 @@ static bool iommufd_device_is_attached(struct iommufd_device *idev) 
{

	struct iommufd_device *cur;



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

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

		if (cur == idev)

			return true;

	return false;
@@ -493,19 +497,33 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, 
	struct iommufd_hwpt_paging *hwpt_paging = find_hwpt_paging(hwpt);

	bool attach_resv = hwpt_paging && pasid == IOMMU_NO_PASID;

	struct iommufd_group *igroup = idev->igroup;

	struct iommufd_hw_pagetable *old_hwpt;

	struct iommufd_attach *attach;

	int rc;



	mutex_lock(&igroup->lock);



	if (igroup->hwpt && igroup->hwpt != hwpt) {

		rc = -EINVAL;

	attach = igroup->attach;

	if (!attach) {

		attach = kzalloc(sizeof(*attach), GFP_KERNEL);

		if (!attach) {

			rc = -ENOMEM;

			goto err_unlock;

		}

		INIT_LIST_HEAD(&attach->device_list);

	}



	old_hwpt = attach->hwpt;



	if (old_hwpt && old_hwpt != hwpt) {

		rc = -EINVAL;

		goto err_free_attach;

	}



	if (attach_resv) {

		rc = iommufd_device_attach_reserved_iova(idev, hwpt_paging);

		if (rc)

			goto err_unlock;

			goto err_free_attach;

	}



	/*
@@ -519,15 +537,19 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt, 
		rc = iommufd_hwpt_attach_device(hwpt, idev, pasid);

		if (rc)

			goto err_unresv;

		igroup->hwpt = hwpt;

		attach->hwpt = hwpt;

		igroup->attach = attach;

	}

	refcount_inc(&hwpt->obj.users);

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

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

	mutex_unlock(&igroup->lock);

	return 0;

err_unresv:

	if (attach_resv)

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

err_free_attach:

	if (iommufd_group_first_attach(igroup, pasid))

		kfree(attach);

err_unlock:

	mutex_unlock(&igroup->lock);

	return rc;
@@ -537,14 +559,20 @@ struct iommufd_hw_pagetable * 
iommufd_hw_pagetable_detach(struct iommufd_device *idev, ioasid_t pasid)

{

	struct iommufd_group *igroup = idev->igroup;

	struct iommufd_hw_pagetable *hwpt = igroup->hwpt;

	struct iommufd_hwpt_paging *hwpt_paging = find_hwpt_paging(hwpt);

	struct iommufd_hwpt_paging *hwpt_paging;

	struct iommufd_hw_pagetable *hwpt;

	struct iommufd_attach *attach;



	mutex_lock(&igroup->lock);

	attach = igroup->attach;

	hwpt = attach->hwpt;

	hwpt_paging = find_hwpt_paging(hwpt);



	list_del(&idev->group_item);

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

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

		iommufd_hwpt_detach_device(hwpt, idev, pasid);

		igroup->hwpt = NULL;

		igroup->attach = NULL;

		kfree(attach);

	}

	if (hwpt_paging && pasid == IOMMU_NO_PASID)

		iopt_remove_reserved_iova(&hwpt_paging->ioas->iopt, idev->dev);
@@ -574,7 +602,7 @@ iommufd_group_remove_reserved_iova(struct iommufd_group *igroup, 


	lockdep_assert_held(&igroup->lock);



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

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

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

}
@@ -588,9 +616,10 @@ iommufd_group_do_replace_reserved_iova(struct iommufd_group *igroup, 


	lockdep_assert_held(&igroup->lock);



	old_hwpt_paging = find_hwpt_paging(igroup->hwpt);

	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->device_list, group_item) {

		list_for_each_entry(cur,

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

			rc = iopt_table_enforce_dev_resv_regions(

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

			if (rc)
@@ -617,27 +646,32 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid, 
	struct iommufd_hwpt_paging *old_hwpt_paging;

	struct iommufd_group *igroup = idev->igroup;

	struct iommufd_hw_pagetable *old_hwpt;

	struct iommufd_attach *attach;

	unsigned int num_devices;

	int rc;



	mutex_lock(&igroup->lock);



	if (igroup->hwpt == NULL) {

	attach = igroup->attach;

	if (!attach) {

		rc = -EINVAL;

		goto err_unlock;

	}



	old_hwpt = attach->hwpt;



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



	if (!iommufd_device_is_attached(idev)) {

		rc = -EINVAL;

		goto err_unlock;

	}



	if (hwpt == igroup->hwpt) {

	if (hwpt == old_hwpt) {

		mutex_unlock(&igroup->lock);

		return NULL;

	}



	old_hwpt = igroup->hwpt;

	if (attach_resv) {

		rc = iommufd_group_do_replace_reserved_iova(igroup, hwpt_paging);

		if (rc)
@@ -653,9 +687,9 @@ iommufd_device_do_replace(struct iommufd_device *idev, ioasid_t pasid, 
	    (!hwpt_paging || hwpt_paging->ioas != old_hwpt_paging->ioas))

		iommufd_group_remove_reserved_iova(igroup, old_hwpt_paging);



	igroup->hwpt = hwpt;

	attach->hwpt = hwpt;



	num_devices = list_count_nodes(&igroup->device_list);

	num_devices = list_count_nodes(&attach->device_list);

	/*

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

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

drivers/iommu/iommufd/iommufd_private.h

+3 −2
Original line number Diff line number Diff line
@@ -399,13 +399,14 @@ static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx, 
	refcount_dec(&hwpt->obj.users);

}



struct iommufd_attach;



struct iommufd_group {

	struct kref ref;

	struct mutex lock;

	struct iommufd_ctx *ictx;

	struct iommu_group *group;

	struct iommufd_hw_pagetable *hwpt;

	struct list_head device_list;

	struct iommufd_attach *attach;

	struct iommufd_sw_msi_maps required_sw_msi;

	phys_addr_t sw_msi_start;

};