[Qemu-devel] [PATCH v2] memory: add section range info for IOMMU notifier

[Peter Xu <peterx@redhat.com>]

In this patch, IOMMUNotifier.{start|end} are introduced to store section
information for a specific notifier. When notification occurs, we not
only check the notification type (MAP|UNMAP), but also check whether the
notified iova is in the range of specific IOMMU notifier, and skip those
notifiers if not in the listened range.

When removing an region, we need to make sure we removed the correct
VFIOGuestIOMMU by checking the IOMMUNotifier.start address as well.

Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
v2:
- replace offset_within_address_space with offset_within_region since
  IOTLB iova is relative to region [David]
---
 hw/vfio/common.c      | 7 ++++++-
 include/exec/memory.h | 3 +++
 memory.c              | 4 +++-
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 801578b..6f648da 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -455,6 +455,10 @@ static void vfio_listener_region_add(MemoryListener *listener,
         giommu->container = container;
         giommu->n.notify = vfio_iommu_map_notify;
         giommu->n.notifier_flags = IOMMU_NOTIFIER_ALL;
+        giommu->n.start = section->offset_within_region;
+        llend = int128_add(int128_make64(giommu->n.start), section->size);
+        llend = int128_sub(llend, int128_one());
+        giommu->n.end = int128_get64(llend);
         QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
 
         memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
@@ -525,7 +529,8 @@ static void vfio_listener_region_del(MemoryListener *listener,
         VFIOGuestIOMMU *giommu;
 
         QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
-            if (giommu->iommu == section->mr) {
+            if (giommu->iommu == section->mr &&
+                giommu->n.start == section->offset_within_region) {
                 memory_region_unregister_iommu_notifier(giommu->iommu,
                                                         &giommu->n);
                 QLIST_REMOVE(giommu, giommu_next);
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 9728a2f..87357ea 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -84,6 +84,9 @@ typedef enum {
 struct IOMMUNotifier {
     void (*notify)(struct IOMMUNotifier *notifier, IOMMUTLBEntry *data);
     IOMMUNotifierFlag notifier_flags;
+    /* Notify for address space range start <= addr <= end */
+    hwaddr start;
+    hwaddr end;
     QLIST_ENTRY(IOMMUNotifier) node;
 };
 typedef struct IOMMUNotifier IOMMUNotifier;
diff --git a/memory.c b/memory.c
index 33110e9..f89d047 100644
--- a/memory.c
+++ b/memory.c
@@ -1662,7 +1662,9 @@ void memory_region_notify_iommu(MemoryRegion *mr,
     }
 
     QLIST_FOREACH(iommu_notifier, &mr->iommu_notify, node) {
-        if (iommu_notifier->notifier_flags & request_flags) {
+        if (iommu_notifier->notifier_flags & request_flags &&
+            iommu_notifier->start <= entry.iova &&
+            iommu_notifier->end >= entry.iova) {
             iommu_notifier->notify(iommu_notifier, &entry);
         }
     }
-- 
2.7.4