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iommu: Introduce iommu_request_dm_for_dev()

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

Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Joerg Roedel 2015-05-28 18:41:36 +02:00
parent 6827ca8369
commit d290f1e70d
2 changed files with 59 additions and 0 deletions
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53
drivers/iommu/iommu.c
View File

@ -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;
}

6
include/linux/iommu.h
View File

@ -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)
{