iommu: Implement reserved_regions iommu-group sysfs file

		file if the IOMMU driver has chosen to register a more

		common name for the group.

Users:

What:		/sys/kernel/iommu_groups/reserved_regions

Date: 		January 2017

KernelVersion:  v4.11

Contact: 	Eric Auger <eric.auger@redhat.com>

Description:    /sys/kernel/iommu_groups/reserved_regions list IOVA

		regions that are reserved. Not necessarily all

		reserved regions are listed. This is typically used to

		output direct-mapped, MSI, non mappable regions. Each

		region is described on a single line: the 1st field is

		the base IOVA, the second is the end IOVA and the third

		field describes the type of the region.

			 const char *buf, size_t count);

};

static const char * const iommu_group_resv_type_string[] = {

	[IOMMU_RESV_DIRECT]	= "direct",

	[IOMMU_RESV_RESERVED]	= "reserved",

	[IOMMU_RESV_MSI]	= "msi",

};

#define IOMMU_GROUP_ATTR(_name, _mode, _show, _store)		\

struct iommu_group_attribute iommu_group_attr_##_name =		\

	__ATTR(_name, _mode, _show, _store)

}

EXPORT_SYMBOL_GPL(iommu_get_group_resv_regions);

static ssize_t iommu_group_show_resv_regions(struct iommu_group *group,

					     char *buf)

{

	struct iommu_resv_region *region, *next;

	struct list_head group_resv_regions;

	char *str = buf;

	INIT_LIST_HEAD(&group_resv_regions);

	iommu_get_group_resv_regions(group, &group_resv_regions);

	list_for_each_entry_safe(region, next, &group_resv_regions, list) {

		str += sprintf(str, "0x%016llx 0x%016llx %s\n",

			       (long long int)region->start,

			       (long long int)(region->start +

						region->length - 1),

			       iommu_group_resv_type_string[region->type]);

		kfree(region);

	}

	return (str - buf);

}

static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL);

static IOMMU_GROUP_ATTR(reserved_regions, 0444,

			iommu_group_show_resv_regions, NULL);

static void iommu_group_release(struct kobject *kobj)

{

	struct iommu_group *group = to_iommu_group(kobj);

	 */

	kobject_put(&group->kobj);

	ret = iommu_group_create_file(group,

				      &iommu_group_attr_reserved_regions);

	if (ret)

		return ERR_PTR(ret);

	pr_debug("Allocated group %d\n", group->id);

	return group;