1 files changed, 60 insertions, 0 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 14d6f908196b..2198b2dbbcd3 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -27,8 +27,59 @@
 #include <linux/errno.h>
 #include <linux/iommu.h>
 
+static ssize_t show_iommu_group(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	unsigned int groupid;
+
+	if (iommu_device_group(dev, &groupid))
+		return 0;
+
+	return sprintf(buf, "%u", groupid);
+}
+static DEVICE_ATTR(iommu_group, S_IRUGO, show_iommu_group, NULL);
+
+static int add_iommu_group(struct device *dev, void *data)
+{
+	unsigned int groupid;
+
+	if (iommu_device_group(dev, &groupid) == 0)
+		return device_create_file(dev, &dev_attr_iommu_group);
+
+	return 0;
+}
+
+static int remove_iommu_group(struct device *dev)
+{
+	unsigned int groupid;
+
+	if (iommu_device_group(dev, &groupid) == 0)
+		device_remove_file(dev, &dev_attr_iommu_group);
+
+	return 0;
+}
+
+static int iommu_device_notifier(struct notifier_block *nb,
+				 unsigned long action, void *data)
+{
+	struct device *dev = data;
+
+	if (action == BUS_NOTIFY_ADD_DEVICE)
+		return add_iommu_group(dev, NULL);
+	else if (action == BUS_NOTIFY_DEL_DEVICE)
+		return remove_iommu_group(dev);
+
+	return 0;
+}
+
+static struct notifier_block iommu_device_nb = {
+	.notifier_call = iommu_device_notifier,
+};
+
 static void iommu_bus_init(struct bus_type *bus, struct iommu_ops *ops)
 {
+	bus_register_notifier(bus, &iommu_device_nb);
+	bus_for_each_dev(bus, NULL, NULL, add_iommu_group);
 }
 
 /**
@@ -281,3 +332,12 @@ size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size)
 	return unmapped;
 }
 EXPORT_SYMBOL_GPL(iommu_unmap);
+
+int iommu_device_group(struct device *dev, unsigned int *groupid)
+{
+	if (iommu_present(dev->bus) && dev->bus->iommu_ops->device_group)
+		return dev->bus->iommu_ops->device_group(dev, groupid);
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(iommu_device_group);