[Qemu-devel] [PATCH RFC v4 10/20] 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>
---
changelog (start from vt-d vfio enablement series v3):
v4:
- introduce memory_region_iommu_notifier_init() [Jason]
---
 hw/vfio/common.c      | 12 +++++++++---
 hw/virtio/vhost.c     |  4 ++--
 include/exec/memory.h | 19 ++++++++++++++++++-
 memory.c              |  5 ++++-
 4 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 4d90844..49dc035 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -471,8 +471,13 @@ static void vfio_listener_region_add(MemoryListener *listener,
         giommu->iommu_offset = section->offset_within_address_space -
                                section->offset_within_region;
         giommu->container = container;
-        giommu->n.notify = vfio_iommu_map_notify;
-        giommu->n.notifier_flags = IOMMU_NOTIFIER_ALL;
+        llend = int128_add(int128_make64(section->offset_within_region),
+                           section->size);
+        llend = int128_sub(llend, int128_one());
+        iommu_notifier_init(&giommu->n, vfio_iommu_map_notify,
+                            IOMMU_NOTIFIER_ALL,
+                            section->offset_within_region,
+                            int128_get64(llend));
         QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
 
         memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
@@ -543,7 +548,8 @@ 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/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 9cacf55..cc99c6a 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1242,8 +1242,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
         .priority = 10
     };
 
-    hdev->n.notify = vhost_iommu_unmap_notify;
-    hdev->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
+    iommu_notifier_init(&hdev->n, vhost_iommu_unmap_notify,
+                        IOMMU_NOTIFIER_UNMAP, 0, ~0ULL);
 
     if (hdev->migration_blocker == NULL) {
         if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) {
diff --git a/include/exec/memory.h b/include/exec/memory.h
index bec9756..ae4c9a9 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -81,13 +81,30 @@ typedef enum {
 
 #define IOMMU_NOTIFIER_ALL (IOMMU_NOTIFIER_MAP | IOMMU_NOTIFIER_UNMAP)
 
+struct IOMMUNotifier;
+typedef void (*IOMMUNotify)(struct IOMMUNotifier *notifier,
+                            IOMMUTLBEntry *data);
+
 struct IOMMUNotifier {
-    void (*notify)(struct IOMMUNotifier *notifier, IOMMUTLBEntry *data);
+    IOMMUNotify notify;
     IOMMUNotifierFlag notifier_flags;
+    /* Notify for address space range start <= addr <= end */
+    hwaddr start;
+    hwaddr end;
     QLIST_ENTRY(IOMMUNotifier) node;
 };
 typedef struct IOMMUNotifier IOMMUNotifier;
 
+static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
+                                       IOMMUNotifierFlag flags,
+                                       hwaddr start, hwaddr end)
+{
+    n->notify = fn;
+    n->notifier_flags = flags;
+    n->start = start;
+    n->end = end;
+}
+
 /* New-style MMIO accessors can indicate that the transaction failed.
  * A zero (MEMTX_OK) response means success; anything else is a failure
  * of some kind. The memory subsystem will bitwise-OR together results
diff --git a/memory.c b/memory.c
index 2bfc37f..89104b1 100644
--- a/memory.c
+++ b/memory.c
@@ -1610,6 +1610,7 @@ void memory_region_register_iommu_notifier(MemoryRegion *mr,
 
     /* We need to register for at least one bitfield */
     assert(n->notifier_flags != IOMMU_NOTIFIER_NONE);
+    assert(n->start <= n->end);
     QLIST_INSERT_HEAD(&mr->iommu_notify, n, node);
     memory_region_update_iommu_notify_flags(mr);
 }
@@ -1671,7 +1672,9 @@ 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