memory: introduce memory_region_notify_one()

Generalizing the notify logic in memory_region_notify_iommu() into a
single function. This can be further used in customized replay()
functions for IOMMUs.
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Reviewed-by: N\"Michael S. Tsirkin\" <mst@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <1491562755-23867-5-git-send-email-peterx@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

include/exec/memory.h

@@ -687,6 +687,21 @@ uint64_t memory_region_iommu_get_min_page_size(MemoryRegion *mr);
 void memory_region_notify_iommu(MemoryRegion *mr,
                                 IOMMUTLBEntry entry);
 
+/**
+ * memory_region_notify_one: notify a change in an IOMMU translation
+ *                           entry to a single notifier
+ *
+ * This works just like memory_region_notify_iommu(), but it only
+ * notifies a specific notifier, not all of them.
+ *
+ * @notifier: the notifier to be notified
+ * @entry: the new entry in the IOMMU translation table.  The entry
+ *         replaces all old entries for the same virtual I/O address range.
+ *         Deleted entries have .@perm == 0.
+ */
+void memory_region_notify_one(IOMMUNotifier *notifier,
+                              IOMMUTLBEntry *entry);
+
 /**
  * memory_region_register_iommu_notifier: register a notifier for changes to
  * IOMMU translation entries.

memory.c

@@ -1662,32 +1662,40 @@ void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
     memory_region_update_iommu_notify_flags(mr);
 }
 
-void memory_region_notify_iommu(MemoryRegion *mr,
-                                IOMMUTLBEntry entry)
+void memory_region_notify_one(IOMMUNotifier *notifier,
+                              IOMMUTLBEntry *entry)
 {
-    IOMMUNotifier *iommu_notifier;
     IOMMUNotifierFlag request_flags;
 
-    assert(memory_region_is_iommu(mr));
+    /*
+     * Skip the notification if the notification does not overlap
+     * with registered range.
+     */
+    if (notifier->start > entry->iova + entry->addr_mask + 1 ||
+        notifier->end < entry->iova) {
+        return;
+    }
 
-    if (entry.perm & IOMMU_RW) {
+    if (entry->perm & IOMMU_RW) {
         request_flags = IOMMU_NOTIFIER_MAP;
     } else {
         request_flags = IOMMU_NOTIFIER_UNMAP;
     }
 
+    if (notifier->notifier_flags & request_flags) {
+        notifier->notify(notifier, entry);
+    }
+}
+
+void memory_region_notify_iommu(MemoryRegion *mr,
+                                IOMMUTLBEntry entry)
+{
+    IOMMUNotifier *iommu_notifier;
+
+    assert(memory_region_is_iommu(mr));
+
     IOMMU_NOTIFIER_FOREACH(iommu_notifier, mr) {
-        /*
-         * Skip the notification if the notification does not overlap
-         * with registered range.
-         */
-        if (iommu_notifier->start > entry.iova + entry.addr_mask + 1 ||
-            iommu_notifier->end < entry.iova) {
-            continue;
-        }
-        if (iommu_notifier->notifier_flags & request_flags) {
-            iommu_notifier->notify(iommu_notifier, &entry);
-        }
+        memory_region_notify_one(iommu_notifier, &entry);
     }
 }