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iommu: Revise iommu_group_alloc_default_domain()

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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: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/13-v5-1b99ae392328+44574-iommu_err_unwind_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Jason Gunthorpe 2023-05-11 01:42:11 -03:00 • committed by Joerg Roedel
parent 8b4eb75ee5
commit fcbb0a4d73
1 changed files with 38 additions and 35 deletions
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73
drivers/iommu/iommu.c
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@ -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 (req_type)
return __iommu_domain_alloc(bus, req_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;
/* 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 -ENOMEM;
return NULL;
group->default_domain = dom;
return 0;
}
static int iommu_alloc_default_domain(struct iommu_group *group,
struct device *dev)
{
unsigned int type;
type = iommu_get_def_domain_type(dev) ? : iommu_def_domain_type;
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);