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Commit d290f1e7 authored by Joerg Roedel's avatar Joerg Roedel
Browse files

iommu: Introduce iommu_request_dm_for_dev() 



This function can be called by an IOMMU driver to request
that a device's default domain is direct mapped.

Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 6827ca83

drivers/iommu/iommu.c

+53 −0
Original line number Diff line number Diff line
@@ -1538,3 +1538,56 @@ void iommu_put_dm_regions(struct device *dev, struct list_head *list) 
	if (ops && ops->put_dm_regions)

		ops->put_dm_regions(dev, list);

}



/* Request that a device is direct mapped by the IOMMU */

int iommu_request_dm_for_dev(struct device *dev)

{

	struct iommu_domain *dm_domain;

	struct iommu_group *group;

	int ret;



	/* Device must already be in a group before calling this function */

	group = iommu_group_get_for_dev(dev);

	if (!group)

		return -EINVAL;



	mutex_lock(&group->mutex);



	/* Check if the default domain is already direct mapped */

	ret = 0;

	if (group->default_domain &&

	    group->default_domain->type == IOMMU_DOMAIN_IDENTITY)

		goto out;



	/* Don't change mappings of existing devices */

	ret = -EBUSY;

	if (iommu_group_device_count(group) != 1)

		goto out;



	/* Allocate a direct mapped domain */

	ret = -ENOMEM;

	dm_domain = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_IDENTITY);

	if (!dm_domain)

		goto out;



	/* Attach the device to the domain */

	ret = __iommu_attach_group(dm_domain, group);

	if (ret) {

		iommu_domain_free(dm_domain);

		goto out;

	}



	/* Make the direct mapped domain the default for this group */

	if (group->default_domain)

		iommu_domain_free(group->default_domain);

	group->default_domain = dm_domain;



	pr_info("Using direct mapping for device %s\n", dev_name(dev));



	ret = 0;

out:

	mutex_unlock(&group->mutex);

	iommu_group_put(group);



	return ret;

}

include/linux/iommu.h

+6 −0
Original line number Diff line number Diff line
@@ -225,6 +225,7 @@ extern void iommu_set_fault_handler(struct iommu_domain *domain, 


extern void iommu_get_dm_regions(struct device *dev, struct list_head *list);

extern void iommu_put_dm_regions(struct device *dev, struct list_head *list);

extern int iommu_request_dm_for_dev(struct device *dev);



extern int iommu_attach_group(struct iommu_domain *domain,

			      struct iommu_group *group);
@@ -411,6 +412,11 @@ static inline void iommu_put_dm_regions(struct device *dev, 
{

}



static inline int iommu_request_dm_for_dev(struct device *dev)

{

	return -ENODEV;

}



static inline int iommu_attach_group(struct iommu_domain *domain,

				     struct iommu_group *group)

{