Commit fcbb0a4d authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Joerg Roedel
Browse files

iommu: Revise iommu_group_alloc_default_domain() 



Robin points out that the fallback to guessing what domains the driver
supports should only happen if the driver doesn't return a preference from
its ops->def_domain_type().

Re-organize iommu_group_alloc_default_domain() so it internally uses
iommu_def_domain_type only during the fallback and makes it clearer how
the fallback sequence works.

Make iommu_group_alloc_default_domain() return the domain so the return
based logic is cleaner and to prepare for the next patch.

Remove the iommu_alloc_default_domain() function as it is now trivially
just calling iommu_group_alloc_default_domain().

Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Tested-by: default avatarHeiko Stuebner <heiko@sntech.de>
Tested-by: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/13-v5-1b99ae392328+44574-iommu_err_unwind_jgg@nvidia.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 8b4eb75e

drivers/iommu/iommu.c

+37 −34
Original line number Diff line number Diff line
@@ -93,8 +93,9 @@ static const char * const iommu_group_resv_type_string[] = { 
static int iommu_bus_notifier(struct notifier_block *nb,

			      unsigned long action, void *data);

static void iommu_release_device(struct device *dev);

static int iommu_alloc_default_domain(struct iommu_group *group,

				      struct device *dev);

static struct iommu_domain *

iommu_group_alloc_default_domain(struct iommu_group *group, int req_type);

static int iommu_get_def_domain_type(struct device *dev);

static struct iommu_domain *__iommu_domain_alloc(const struct bus_type *bus,

						 unsigned type);

static int __iommu_attach_device(struct iommu_domain *domain,
@@ -434,7 +435,8 @@ int iommu_probe_device(struct device *dev) 
		 * support default domains, so the return value is not yet

		 * checked.

		 */

		iommu_alloc_default_domain(group, dev);

		group->default_domain = iommu_group_alloc_default_domain(

			group, iommu_get_def_domain_type(dev));

		if (group->default_domain) {

			iommu_create_device_direct_mappings(group, dev);

			ret = __iommu_group_set_domain(group,
@@ -1645,35 +1647,38 @@ static int iommu_get_def_domain_type(struct device *dev) 
	return 0;

}



static int iommu_group_alloc_default_domain(const struct bus_type *bus,

					    struct iommu_group *group,

					    unsigned int type)

/*

 * req_type of 0 means "auto" which means to select a domain based on

 * iommu_def_domain_type or what the driver actually supports.

 */

static struct iommu_domain *

iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)

{

	const struct bus_type *bus =

		list_first_entry(&group->devices, struct group_device, list)

			->dev->bus;

	struct iommu_domain *dom;



	dom = __iommu_domain_alloc(bus, type);

	if (!dom && type != IOMMU_DOMAIN_DMA) {

		dom = __iommu_domain_alloc(bus, IOMMU_DOMAIN_DMA);

		if (dom)

			pr_warn("Failed to allocate default IOMMU domain of type %u for group %s - Falling back to IOMMU_DOMAIN_DMA",

				type, group->name);

	}

	lockdep_assert_held(&group->mutex);



	if (!dom)

		return -ENOMEM;

	if (req_type)

		return __iommu_domain_alloc(bus, req_type);



	group->default_domain = dom;

	return 0;

}



static int iommu_alloc_default_domain(struct iommu_group *group,

				      struct device *dev)

{

	unsigned int type;

	/* The driver gave no guidance on what type to use, try the default */

	dom = __iommu_domain_alloc(bus, iommu_def_domain_type);

	if (dom)

		return dom;



	type = iommu_get_def_domain_type(dev) ? : iommu_def_domain_type;

	/* Otherwise IDENTITY and DMA_FQ defaults will try DMA */

	if (iommu_def_domain_type == IOMMU_DOMAIN_DMA)

		return NULL;

	dom = __iommu_domain_alloc(bus, IOMMU_DOMAIN_DMA);

	if (!dom)

		return NULL;



	return iommu_group_alloc_default_domain(dev->bus, group, type);

	pr_warn("Failed to allocate default IOMMU domain of type %u for group %s - Falling back to IOMMU_DOMAIN_DMA",

		iommu_def_domain_type, group->name);

	return dom;

}



/**
@@ -1785,15 +1790,12 @@ static int iommu_get_default_domain_type(struct iommu_group *group, 
				"Device needs domain type %s, but device %s in the same iommu group requires type %s - using default\n",

				iommu_domain_type_str(type), dev_name(last_dev),

				iommu_domain_type_str(best_type));

			return iommu_def_domain_type;

			return 0;

		}

		if (!best_type)

			best_type = type;

		last_dev = gdev->dev;

	}



	if (!best_type)

		return iommu_def_domain_type;

	return best_type;

}
@@ -1850,9 +1852,8 @@ int bus_iommu_probe(const struct bus_type *bus) 
		list_del_init(&group->entry);



		/* Try to allocate default domain */

		iommu_group_alloc_default_domain(

			bus, group, iommu_get_default_domain_type(group, 0));



		group->default_domain = iommu_group_alloc_default_domain(

			group, iommu_get_default_domain_type(group, 0));

		if (!group->default_domain) {

			mutex_unlock(&group->mutex);

			continue;
@@ -2897,9 +2898,11 @@ static int iommu_change_dev_def_domain(struct iommu_group *group, 
	group->domain = NULL;



	/* Sets group->default_domain to the newly allocated domain */

	ret = iommu_group_alloc_default_domain(dev->bus, group, type);

	if (ret)

	group->default_domain = iommu_group_alloc_default_domain(group, type);

	if (!group->default_domain) {

		ret = -EINVAL;

		goto restore_old_domain;

	}



	group->domain = prev_dom;

	ret = iommu_create_device_direct_mappings(group, dev);