[PATCH v3 08/34] iommu: Move default domain allocation to iommu_probe_device()

Joerg Roedel
2020-04-29T13:38:33Z

Well, not really. The call to iommu_alloc_default_domain() in
iommu_group_get_for_dev() has to stay around as long as there are
IOMMU drivers using the add/remove_device() call-backs instead of
probe/release_device().

Those drivers expect that iommu_group_get_for_dev() returns the device
attached to a group and the group set up with a default domain (and
the device attached to the groups current domain).

But when all drivers are converted this compatability mess can be
removed.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/iommu.c | 102 +++++++++++++++++++++++++++++-------------
1 file changed, 71 insertions(+), 31 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 6cfe7799dc8c..7a385c18e1a5 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -79,6 +79,16 @@ static bool iommu_cmd_line_dma_api(void)
return !!(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API);
}

+static int iommu_alloc_default_domain(struct device *dev);
+static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
+ unsigned type);
+static int __iommu_attach_device(struct iommu_domain *domain,
+ struct device *dev);
+static int __iommu_attach_group(struct iommu_domain *domain,
+ struct iommu_group *group);
+static void __iommu_detach_group(struct iommu_domain *domain,
+ struct iommu_group *group);
+
#define IOMMU_GROUP_ATTR(_name, _mode, _show, _store) \
struct iommu_group_attribute iommu_group_attr_##_name = \
__ATTR(_name, _mode, _show, _store)
@@ -221,10 +231,29 @@ int iommu_probe_device(struct device *dev)
goto err_free_dev_param;
}

- if (ops->probe_device)
+ if (ops->probe_device) {
+ struct iommu_group *group;
+
ret = __iommu_probe_device(dev);
- else
+
+ /*
+ * Try to allocate a default domain - needs support from the
+ * IOMMU driver. There are still some drivers which don't
+ * support default domains, so the return value is not yet
+ * checked.
+ */
+ if (!ret)
+ iommu_alloc_default_domain(dev);
+
+ group = iommu_group_get(dev);
+ if (group && group->default_domain) {
+ ret = __iommu_attach_device(group->default_domain, dev);
+ iommu_group_put(group);
+ }
+
+ } else {
ret = ops->add_device(dev);
+ }

if (ret)
goto err_module_put;
@@ -268,15 +297,6 @@ void iommu_release_device(struct device *dev)
dev_iommu_free(dev);
}

-static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
- unsigned type);
-static int __iommu_attach_device(struct iommu_domain *domain,
- struct device *dev);
-static int __iommu_attach_group(struct iommu_domain *domain,
- struct iommu_group *group);
-static void __iommu_detach_group(struct iommu_domain *domain,
- struct iommu_group *group);
-
static int __init iommu_set_def_domain_type(char *str)
{
bool pt;
@@ -1423,25 +1443,18 @@ static int iommu_get_def_domain_type(struct device *dev)
return (type == 0) ? iommu_def_domain_type : type;
}

-static int iommu_alloc_default_domain(struct device *dev,
- struct iommu_group *group)
+static int iommu_group_alloc_default_domain(struct bus_type *bus,
+ struct iommu_group *group,
+ unsigned int type)
{
struct iommu_domain *dom;
- unsigned int type;
-
- if (group->default_domain)
- return 0;

- type = iommu_get_def_domain_type(dev);
-
- dom = __iommu_domain_alloc(dev->bus, type);
+ dom = __iommu_domain_alloc(bus, type);
if (!dom && type != IOMMU_DOMAIN_DMA) {
- dom = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_DMA);
- if (dom) {
- dev_warn(dev,
- "failed to allocate default IOMMU domain of type %u; falling back to IOMMU_DOMAIN_DMA",
- type);
- }
+ 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);
}

if (!dom)
@@ -1461,6 +1474,23 @@ static int iommu_alloc_default_domain(struct device *dev,
return 0;
}

+static int iommu_alloc_default_domain(struct device *dev)
+{
+ struct iommu_group *group;
+ unsigned int type;
+
+ group = iommu_group_get(dev);
+ if (!group)
+ return -ENODEV;
+
+ if (group->default_domain)
+ return 0;
+
+ type = iommu_get_def_domain_type(dev);
+
+ return iommu_group_alloc_default_domain(dev->bus, group, type);
+}
+
/**
* iommu_group_get_for_dev - Find or create the IOMMU group for a device
* @dev: target device
@@ -1491,16 +1521,26 @@ struct iommu_group *iommu_group_get_for_dev(struct device *dev)
if (IS_ERR(group))
return group;

+ ret = iommu_group_add_device(group, dev);
+ if (ret)
+ goto out_put_group;
+
/*
* Try to allocate a default domain - needs support from the
* IOMMU driver. There are still some drivers which don't support
- * default domains, so the return value is not yet checked.
+ * default domains, so the return value is not yet checked. Only
+ * allocate the domain here when the driver still has the
+ * add_device/remove_device call-backs implemented.
*/
- iommu_alloc_default_domain(dev, group);
+ if (!ops->probe_device) {
+ iommu_alloc_default_domain(dev);

- ret = iommu_group_add_device(group, dev);
- if (ret)
- goto out_put_group;
+ if (group->default_domain)
+ ret = __iommu_attach_device(group->default_domain, dev);
+
+ if (ret)
+ goto out_put_group;
+ }

return group;