iommu: Limit iommu_attach/detach_device to devices with their own group

This patch changes the behavior of the iommu_attach_device
and iommu_detach_device functions. With this change these
functions only work on devices that have their own group.
For all other devices the iommu_group_attach/detach
functions must be used.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 49eb9bf..ef73923 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -433,6 +433,17 @@ void iommu_group_remove_device(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(iommu_group_remove_device);
 
+static int iommu_group_device_count(struct iommu_group *group)
+{
+       struct iommu_device *entry;
+       int ret = 0;
+
+       list_for_each_entry(entry, &group->devices, list)
+               ret++;
+
+       return ret;
+}
+
 /**
  * iommu_group_for_each_dev - iterate over each device in the group
  * @group: the group
@@ -969,7 +980,8 @@ void iommu_domain_free(struct iommu_domain *domain)
 }
 EXPORT_SYMBOL_GPL(iommu_domain_free);
 
-int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
+static int __iommu_attach_device(struct iommu_domain *domain,
+                                struct device *dev)
 {
        int ret;
        if (unlikely(domain->ops->attach_dev == NULL))
@@ -980,9 +992,38 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
                trace_attach_device_to_domain(dev);
        return ret;
 }
+
+int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
+{
+       struct iommu_group *group;
+       int ret;
+
+       group = iommu_group_get(dev);
+       /* FIXME: Remove this when groups a mandatory for iommu drivers */
+       if (group == NULL)
+               return __iommu_attach_device(domain, dev);
+
+       /*
+        * We have a group - lock it to make sure the device-count doesn't
+        * change while we are attaching
+        */
+       mutex_lock(&group->mutex);
+       ret = -EINVAL;
+       if (iommu_group_device_count(group) != 1)
+               goto out_unlock;
+
+       ret = __iommu_attach_device(domain, dev);
+
+out_unlock:
+       mutex_unlock(&group->mutex);
+       iommu_group_put(group);
+
+       return ret;
+}
 EXPORT_SYMBOL_GPL(iommu_attach_device);
 
-void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
+static void __iommu_detach_device(struct iommu_domain *domain,
+                                 struct device *dev)
 {
        if (unlikely(domain->ops->detach_dev == NULL))
                return;
@@ -990,6 +1031,28 @@ void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
        domain->ops->detach_dev(domain, dev);
        trace_detach_device_from_domain(dev);
 }
+
+void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
+{
+       struct iommu_group *group;
+
+       group = iommu_group_get(dev);
+       /* FIXME: Remove this when groups a mandatory for iommu drivers */
+       if (group == NULL)
+               return __iommu_detach_device(domain, dev);
+
+       mutex_lock(&group->mutex);
+       if (iommu_group_device_count(group) != 1) {
+               WARN_ON(1);
+               goto out_unlock;
+       }
+
+       __iommu_detach_device(domain, dev);
+
+out_unlock:
+       mutex_unlock(&group->mutex);
+       iommu_group_put(group);
+}
 EXPORT_SYMBOL_GPL(iommu_detach_device);
 
 /*
@@ -1006,7 +1069,7 @@ static int iommu_group_do_attach_device(struct device *dev, void *data)
 {
        struct iommu_domain *domain = data;
 
-       return iommu_attach_device(domain, dev);
+       return __iommu_attach_device(domain, dev);
 }
 
 int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group)
@@ -1020,7 +1083,7 @@ static int iommu_group_do_detach_device(struct device *dev, void *data)
 {
        struct iommu_domain *domain = data;
 
-       iommu_detach_device(domain, dev);
+       __iommu_detach_device(domain, dev);
 
        return 0;
 }