[RFC v3 06/10] iommu: iommu_get_group_resv_regions

[Eric Auger]

Introduce iommu_get_group_resv_regions whose role consists in
enumerating all devices from the group and collecting their
reserved regions. It checks duplicates.

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

---

- we do not move list elements from device to group list since
  the iommu_put_resv_regions() could not be called.
- at the moment I did not introduce any iommu_put_group_resv_regions
  since it simply consists in voiding/freeing the list
---
 drivers/iommu/iommu.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/iommu.h |  8 ++++++++
 2 files changed, 61 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index a4530ad..e0fbcc5 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -133,6 +133,59 @@ static ssize_t iommu_group_show_name(struct iommu_group 
*group, char *buf)
        return sprintf(buf, "%s\n", group->name);
 }
 
+static bool iommu_resv_region_present(struct iommu_resv_region *region,
+                                     struct list_head *head)
+{
+       struct iommu_resv_region *entry;
+
+       list_for_each_entry(entry, head, list) {
+               if ((region->start == entry->start) &&
+                   (region->length == entry->length) &&
+                   (region->prot == entry->prot))
+                       return true;
+       }
+       return false;
+}
+
+static int
+iommu_insert_device_resv_regions(struct list_head *dev_resv_regions,
+                                struct list_head *group_resv_regions)
+{
+       struct iommu_resv_region *entry, *region;
+
+       list_for_each_entry(entry, dev_resv_regions, list) {
+               if (iommu_resv_region_present(entry, group_resv_regions))
+                       continue;
+               region = iommu_alloc_resv_region(entry->start, entry->length,
+                                              entry->prot);
+               if (!region)
+                       return -ENOMEM;
+
+               list_add_tail(&region->list, group_resv_regions);
+       }
+       return 0;
+}
+
+int iommu_get_group_resv_regions(struct iommu_group *group,
+                                struct list_head *head)
+{
+       struct iommu_device *device;
+       int ret = 0;
+
+       list_for_each_entry(device, &group->devices, list) {
+               struct list_head dev_resv_regions;
+
+               INIT_LIST_HEAD(&dev_resv_regions);
+               iommu_get_resv_regions(device->dev, &dev_resv_regions);
+               ret = iommu_insert_device_resv_regions(&dev_resv_regions, head);
+               iommu_put_resv_regions(device->dev, &dev_resv_regions);
+               if (ret)
+                       break;
+       }
+       return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_get_group_resv_regions);
+
 static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL);
 
 static void iommu_group_release(struct kobject *kobj)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 0aea877..0f7ae2c 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -243,6 +243,8 @@ extern void iommu_set_fault_handler(struct iommu_domain 
*domain,
 extern int iommu_request_dm_for_dev(struct device *dev);
 extern struct iommu_resv_region *
 iommu_alloc_resv_region(phys_addr_t start, size_t length, unsigned int prot);
+extern int iommu_get_group_resv_regions(struct iommu_group *group,
+                                       struct list_head *head);
 
 extern int iommu_attach_group(struct iommu_domain *domain,
                              struct iommu_group *group);
@@ -462,6 +464,12 @@ static inline void iommu_put_resv_regions(struct device 
*dev,
        return NULL;
 }
 
+static inline int iommu_get_group_resv_regions(struct iommu_group *group,
+                                              struct list_head *head)
+{
+       return -ENODEV;
+}
+
 static inline int iommu_request_dm_for_dev(struct device *dev)
 {
        return -ENODEV;
-- 
1.9.1