A new iommu-group sysfs attribute file is introduced. It contains
the list of reserved regions for the iommu-group. Each reserved
region is described on a separate line:
- first field is the start IOVA address,
- second is the end IOVA address,

Signed-off-by: Eric Auger <eric.au...@redhat.com>

---

v3 -> v4:
- add cast to long long int when printing to avoid warning on
  i386
- change S_IRUGO into 0444
- remove sort. The list is natively sorted now.

The file layout is inspired of /sys/bus/pci/devices/BDF/resource.
I also read Documentation/filesystems/sysfs.txt so I expect this
to be frowned upon.
---
 drivers/iommu/iommu.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index a2d51b3..15756d8 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -211,8 +211,32 @@ int iommu_get_group_resv_regions(struct iommu_group *group,
 }
 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\n",
+                              (long long int)region->start,
+                              (long long int)(region->start +
+                                               region->length - 1));
+               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);
@@ -227,6 +251,8 @@ static void iommu_group_release(struct kobject *kobj)
        if (group->default_domain)
                iommu_domain_free(group->default_domain);
 
+       iommu_group_remove_file(group, &iommu_group_attr_reserved_regions);
+
        kfree(group->name);
        kfree(group);
 }
@@ -290,6 +316,11 @@ struct iommu_group *iommu_group_alloc(void)
         */
        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;
-- 
1.9.1

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