memory: Adjust event ranges to fit within notifier boundaries

Invalidating the entire address space (i.e. range of [0, ~0ULL]) is a
valid and required operation by vIOMMU implementations. However, such
invalidations currently trigger an assertion unless they originate from
device IOTLB invalidations.

Although in recent Linux guests this case is not exercised by the VTD
implementation due to various optimizations, the assertion will be hit
by upcoming AMD vIOMMU changes to support DMA address translation. More
specifically, when running a Linux guest with VFIO passthrough device,
and a kernel that does not contain commmit 3f2571fed2fa ("iommu/amd:
Remove redundant domain flush from attach_device()").

Remove the assertion altogether and adjust the range to ensure it does
not cross notifier boundaries.

Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Message-Id: <20201116165506.31315-6-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20250919213515.917111-2-alejandro.j.jimenez@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/system/memory.c b/system/memory.c
index cf8cad6961..5c6ccc5c57 100644
--- a/system/memory.c
+++ b/system/memory.c
@@ -2044,13 +2044,9 @@ void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
         return;
     }
 
-    if (notifier->notifier_flags & IOMMU_NOTIFIER_DEVIOTLB_UNMAP) {
-        /* Crop (iova, addr_mask) to range */
-        tmp.iova = MAX(tmp.iova, notifier->start);
-        tmp.addr_mask = MIN(entry_end, notifier->end) - tmp.iova;
-    } else {
-        assert(entry->iova >= notifier->start && entry_end <= notifier->end);
-    }
+    /* Crop (iova, addr_mask) to range */
+    tmp.iova = MAX(tmp.iova, notifier->start);
+    tmp.addr_mask = MIN(entry_end, notifier->end) - tmp.iova;
 
     if (event->type & notifier->notifier_flags) {
         notifier->notify(notifier, &tmp);