[PATCH 3/5] iommu: Limit iommu_attach/detach_device to devices with their own group

Joerg Roedel
2015-01-27T00:10:25Z

From: Joerg Roedel <jroedel@suse.de>

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>
---
drivers/iommu/iommu.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 59 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 8f33ddd3..b63a550 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -51,6 +51,7 @@ struct iommu_group {
void (*iommu_data_release)(void *iommu_data);
char *name;
int id;
+ unsigned dev_cnt;
struct iommu_domain *default_domain;
};

@@ -380,6 +381,7 @@ rename:

mutex_lock(&group->mutex);
list_add_tail(&device->list, &group->devices);
+ group->dev_cnt += 1;
mutex_unlock(&group->mutex);

/* Notify any listeners about change to group. */
@@ -408,6 +410,7 @@ void iommu_group_remove_device(struct device *dev)
IOMMU_GROUP_NOTIFY_DEL_DEVICE, dev);

mutex_lock(&group->mutex);
+ group->dev_cnt -= 1;
list_for_each_entry(tmp_device, &group->devices, list) {
if (tmp_device->dev == dev) {
device = tmp_device;
@@ -943,7 +946,8 @@ 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))
@@ -954,9 +958,38 @@ 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 (group->dev_cnt != 1)
+ goto out_unlock;
+
+ ret = iommu_attach_group(domain, group);
+
+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;
@@ -964,6 +997,28 @@ 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 (group->dev_cnt != 1) {
+ WARN_ON(1);
+ goto out_unlock;
+ }
+
+ iommu_detach_group(domain, group);
+
+out_unlock:
+ mutex_unlock(&group->mutex);
+ iommu_group_put(group);
+}
EXPORT_SYMBOL_GPL(iommu_detach_device);

/*
@@ -980,7 +1035,7 @@ 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)
@@ -994,7 +1049,7 @@ 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;
}
--
1.9.1