iommu: Move default domain allocation to iommu_probe_device()

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.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200429133712.31431-9-joro@8bytes.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 6cfe779..7a385c1 100644 (file)
--- 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;