Commit 3e7f57d1 authored by Lu Baolu's avatar Lu Baolu Committed by Will Deacon
Browse files

iommu: Remove sva handle list 



The struct sva_iommu represents an association between an SVA domain and
a PASID of a device. It's stored in the iommu group's pasid array and also
tracked by a list in the per-mm data structure. Removes duplicate tracking
of sva_iommu by eliminating the list.

Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240702063444.105814-3-baolu.lu@linux.intel.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 14678219

drivers/iommu/iommu-priv.h

+3 −0
Original line number Diff line number Diff line
@@ -28,4 +28,7 @@ void iommu_device_unregister_bus(struct iommu_device *iommu, 
				 const struct bus_type *bus,

				 struct notifier_block *nb);



struct iommu_attach_handle *iommu_attach_handle_get(struct iommu_group *group,

						    ioasid_t pasid,

						    unsigned int type);

#endif /* __LINUX_IOMMU_PRIV_H */

drivers/iommu/iommu-sva.c

+20 −10
Original line number Diff line number Diff line
@@ -41,7 +41,6 @@ static struct iommu_mm_data *iommu_alloc_mm_data(struct mm_struct *mm, struct de 
	}

	iommu_mm->pasid = pasid;

	INIT_LIST_HEAD(&iommu_mm->sva_domains);

	INIT_LIST_HEAD(&iommu_mm->sva_handles);

	/*

	 * Make sure the write to mm->iommu_mm is not reordered in front of

	 * initialization to iommu_mm fields. If it does, readers may see a
@@ -69,11 +68,16 @@ static struct iommu_mm_data *iommu_alloc_mm_data(struct mm_struct *mm, struct de 
 */

struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)

{

	struct iommu_group *group = dev->iommu_group;

	struct iommu_attach_handle *attach_handle;

	struct iommu_mm_data *iommu_mm;

	struct iommu_domain *domain;

	struct iommu_sva *handle;

	int ret;



	if (!group)

		return ERR_PTR(-ENODEV);



	mutex_lock(&iommu_sva_lock);



	/* Allocate mm->pasid if necessary. */
@@ -83,12 +87,22 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm 
		goto out_unlock;

	}



	list_for_each_entry(handle, &mm->iommu_mm->sva_handles, handle_item) {

		if (handle->dev == dev) {

	/* A bond already exists, just take a reference`. */

	attach_handle = iommu_attach_handle_get(group, iommu_mm->pasid, IOMMU_DOMAIN_SVA);

	if (!IS_ERR(attach_handle)) {

		handle = container_of(attach_handle, struct iommu_sva, handle);

		if (attach_handle->domain->mm != mm) {

			ret = -EBUSY;

			goto out_unlock;

		}

		refcount_inc(&handle->users);

		mutex_unlock(&iommu_sva_lock);

		return handle;

	}



	if (PTR_ERR(attach_handle) != -ENOENT) {

		ret = PTR_ERR(attach_handle);

		goto out_unlock;

	}



	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
@@ -99,7 +113,6 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm 


	/* Search for an existing domain. */

	list_for_each_entry(domain, &mm->iommu_mm->sva_domains, next) {

		handle->handle.domain = domain;

		ret = iommu_attach_device_pasid(domain, dev, iommu_mm->pasid,

						&handle->handle);

		if (!ret) {
@@ -115,7 +128,6 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm 
		goto out_free_handle;

	}



	handle->handle.domain = domain;

	ret = iommu_attach_device_pasid(domain, dev, iommu_mm->pasid,

					&handle->handle);

	if (ret)
@@ -125,7 +137,6 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm 


out:

	refcount_set(&handle->users, 1);

	list_add(&handle->handle_item, &mm->iommu_mm->sva_handles);

	mutex_unlock(&iommu_sva_lock);

	handle->dev = dev;

	return handle;
@@ -159,7 +170,6 @@ void iommu_sva_unbind_device(struct iommu_sva *handle) 
		mutex_unlock(&iommu_sva_lock);

		return;

	}

	list_del(&handle->handle_item);



	iommu_detach_device_pasid(domain, dev, iommu_mm->pasid);

	if (--domain->users == 0) {

drivers/iommu/iommu.c

+31 −0
Original line number Diff line number Diff line
@@ -3486,3 +3486,34 @@ void iommu_free_global_pasid(ioasid_t pasid) 
	ida_free(&iommu_global_pasid_ida, pasid);

}

EXPORT_SYMBOL_GPL(iommu_free_global_pasid);



/**

 * iommu_attach_handle_get - Return the attach handle

 * @group: the iommu group that domain was attached to

 * @pasid: the pasid within the group

 * @type: matched domain type, 0 for any match

 *

 * Return handle or ERR_PTR(-ENOENT) on none, ERR_PTR(-EBUSY) on mismatch.

 *

 * Return the attach handle to the caller. The life cycle of an iommu attach

 * handle is from the time when the domain is attached to the time when the

 * domain is detached. Callers are required to synchronize the call of

 * iommu_attach_handle_get() with domain attachment and detachment. The attach

 * handle can only be used during its life cycle.

 */

struct iommu_attach_handle *

iommu_attach_handle_get(struct iommu_group *group, ioasid_t pasid, unsigned int type)

{

	struct iommu_attach_handle *handle;



	xa_lock(&group->pasid_array);

	handle = xa_load(&group->pasid_array, pasid);

	if (!handle)

		handle = ERR_PTR(-ENOENT);

	else if (type && handle->domain->type != type)

		handle = ERR_PTR(-EBUSY);

	xa_unlock(&group->pasid_array);



	return handle;

}

EXPORT_SYMBOL_NS_GPL(iommu_attach_handle_get, IOMMUFD_INTERNAL);

include/linux/iommu.h

+0 −2
Original line number Diff line number Diff line
@@ -1005,14 +1005,12 @@ struct iommu_attach_handle { 
struct iommu_sva {

	struct iommu_attach_handle	handle;

	struct device			*dev;

	struct list_head		handle_item;

	refcount_t			users;

};



struct iommu_mm_data {

	u32			pasid;

	struct list_head	sva_domains;

	struct list_head	sva_handles;

};



int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,