From 8c5154729effda3f762bfb8224f9c61dab8b2986 Mon Sep 17 00:00:00 2001
From: eperezma <eperezma@redhat.com>
Date: Tue, 12 Jan 2021 14:36:38 -0500
Subject: [PATCH 14/17] memory: Skip bad range assertion if notifier is
 DEVIOTLB_UNMAP type
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RH-Author: eperezma <eperezma@redhat.com>
Message-id: <20210112143638.374060-14-eperezma@redhat.com>
Patchwork-id: 100606
O-Subject: [RHEL-8.4.0 qemu-kvm PATCH v2 13/13] memory: Skip bad range assertion if notifier is DEVIOTLB_UNMAP type
Bugzilla: 1843852
RH-Acked-by: Xiao Wang <jasowang@redhat.com>
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: Auger Eric <eric.auger@redhat.com>

Device IOTLB invalidations can unmap arbitrary ranges, eiter outside of
the memory region or even [0, ~0ULL] for all the space. The assertion
could be hit by a guest, and rhel7 guest effectively hit it.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20201116165506.31315-6-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 1804857f19f612f6907832e35599cdb51d4ec764)
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 memory.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/memory.c b/memory.c
index 3bd99b8ac4a..5a4a80842d7 100644
--- a/memory.c
+++ b/memory.c
@@ -1916,6 +1916,7 @@ void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
 {
     IOMMUTLBEntry *entry = &event->entry;
     hwaddr entry_end = entry->iova + entry->addr_mask;
+    IOMMUTLBEntry tmp = *entry;
 
     if (event->type == IOMMU_NOTIFIER_UNMAP) {
         assert(entry->perm == IOMMU_NONE);
@@ -1929,10 +1930,16 @@ void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
         return;
     }
 
-    assert(entry->iova >= notifier->start && entry_end <= notifier->end);
+    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);
+    }
 
     if (event->type & notifier->notifier_flags) {
-        notifier->notify(notifier, entry);
+        notifier->notify(notifier, &tmp);
     }
 }
 
-- 
2.27.0

