[RFC v4 2/2] memory: Skip bad range assertion if notifier is DEVIOTLB type

["Eugenio Pérez" <eperezma@redhat.com>]

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost.c     |  2 +-
 include/exec/memory.h |  2 ++
 softmmu/memory.c      | 15 +++++++++++++--
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 1a1384e7a6..6ca168b47e 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -729,7 +729,7 @@ static void vhost_iommu_region_add(MemoryListener *listener,
     iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
                                                    MEMTXATTRS_UNSPECIFIED);
     iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
-                        IOMMU_NOTIFIER_UNMAP,
+                        IOMMU_NOTIFIER_DEVIOTLB,
                         section->offset_within_region,
                         int128_get64(end),
                         iommu_idx);
diff --git a/include/exec/memory.h b/include/exec/memory.h
index ed99a80f17..74ab71543a 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -87,6 +87,8 @@ typedef enum {
     IOMMU_NOTIFIER_UNMAP = 0x1,
     /* Notify entry changes (newly created entries) */
     IOMMU_NOTIFIER_MAP = 0x2,
+    /* Notify changes on device IOTLB entries */
+    IOMMU_NOTIFIER_DEVIOTLB = 0x04,
 } IOMMUNotifierFlag;
 
 #define IOMMU_NOTIFIER_ALL (IOMMU_NOTIFIER_MAP | IOMMU_NOTIFIER_UNMAP)
diff --git a/softmmu/memory.c b/softmmu/memory.c
index 0043791361..bbc910b129 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -1895,6 +1895,7 @@ void memory_region_notify_one_iommu(IOMMUNotifier *notifier,
 {
     IOMMUNotifierFlag request_flags;
     hwaddr entry_end = entry->iova + entry->addr_mask;
+    IOMMUTLBEntry tmp = *entry;
 
     /*
      * Skip the notification if the notification does not overlap
@@ -1904,16 +1905,26 @@ void memory_region_notify_one_iommu(IOMMUNotifier *notifier,
         return;
     }
 
-    assert(entry->iova >= notifier->start && entry_end <= notifier->end);
+    if (notifier->notifier_flags & IOMMU_NOTIFIER_DEVIOTLB) {
+        /* Crop (iova, addr_mask) to range */
+        tmp.iova = MAX(tmp.iova, notifier->start);
+        tmp.addr_mask = MIN(entry_end, notifier->end) - tmp.iova;
+        /* Confirm no underflow */
+        assert(MIN(entry_end, notifier->end) >= tmp.iova);
+    } else {
+        assert(entry->iova >= notifier->start && entry_end <= notifier->end);
+    }
 
     if (entry->perm & IOMMU_RW) {
         request_flags = IOMMU_NOTIFIER_MAP;
+    } else if (notifier->notifier_flags == IOMMU_NOTIFIER_DEVIOTLB) {
+        request_flags = IOMMU_NOTIFIER_DEVIOTLB;
     } else {
         request_flags = IOMMU_NOTIFIER_UNMAP;
     }
 
     if (notifier->notifier_flags & request_flags) {
-        notifier->notify(notifier, entry);
+        notifier->notify(notifier, &tmp);
     }
 }
 
-- 
2.18.1