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From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
To: qemu-devel@nongnu.org, pbonzini@redhat.com, mst@redhat.com
Cc: peter.maydell@linaro.org, maxime.coquelin@redhat.com,
	marcandre.lureau@redhat.com
Subject: [Qemu-devel] [PATCH v2 3/3] vhost: Fix memory region section comparison
Date: Wed, 14 Aug 2019 18:55:35 +0100	[thread overview]
Message-ID: <20190814175535.2023-4-dgilbert@redhat.com> (raw)
In-Reply-To: <20190814175535.2023-1-dgilbert@redhat.com>

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Using memcmp to compare structures wasn't safe,
as I found out on ARM when I was getting falce miscompares.

Use the helper function for comparing the MRSs.

Fixes: ade6d081fc33948e56e6

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 hw/virtio/vhost.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index bc899fc60e..2ef4bc720f 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -451,8 +451,13 @@ static void vhost_commit(MemoryListener *listener)
         changed = true;
     } else {
         /* Same size, lets check the contents */
-        changed = n_old_sections && memcmp(dev->mem_sections, old_sections,
-                         n_old_sections * sizeof(old_sections[0])) != 0;
+        for (int i = 0; i < n_old_sections; i++) {
+            if (!MemoryRegionSection_eq(&old_sections[i],
+                                        &dev->mem_sections[i])) {
+                changed = true;
+                break;
+            }
+        }
     }
 
     trace_vhost_commit(dev->started, changed);
-- 
2.21.0



WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	qemu-stable@nongnu.org
Subject: [PULL 3/3] vhost: Fix memory region section comparison
Date: Wed, 25 Sep 2019 10:30:20 -0400	[thread overview]
Message-ID: <20190814175535.2023-4-dgilbert@redhat.com> (raw)
Message-ID: <20190925143020.B9J6AcO-Qejkfhp4cS9ej138GeEC4B4NAzupWCgLtC0@z> (raw)
In-Reply-To: <20190925142910.26529-1-mst@redhat.com>

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Using memcmp to compare structures wasn't safe,
as I found out on ARM when I was getting falce miscompares.

Use the helper function for comparing the MRSs.

Fixes: ade6d081fc33948e56e6 ("vhost: Regenerate region list from changed sections list")
Cc: qemu-stable@nongnu.org
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190814175535.2023-4-dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/vhost.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 34accdf615..2386b511f3 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -451,8 +451,13 @@ static void vhost_commit(MemoryListener *listener)
         changed = true;
     } else {
         /* Same size, lets check the contents */
-        changed = n_old_sections && memcmp(dev->mem_sections, old_sections,
-                         n_old_sections * sizeof(old_sections[0])) != 0;
+        for (int i = 0; i < n_old_sections; i++) {
+            if (!MemoryRegionSection_eq(&old_sections[i],
+                                        &dev->mem_sections[i])) {
+                changed = true;
+                break;
+            }
+        }
     }
 
     trace_vhost_commit(dev->started, changed);
-- 
MST



  parent reply	other threads:[~2019-08-14 17:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-14 17:55 [Qemu-devel] [PATCH v2 0/3] Fix MemoryRegionSection alignment and comparison Dr. David Alan Gilbert (git)
2019-08-14 17:55 ` [Qemu-devel] [PATCH v2 1/3] memory: Align MemoryRegionSections fields Dr. David Alan Gilbert (git)
2019-09-25 14:30   ` [PULL " Michael S. Tsirkin
2019-08-14 17:55 ` [Qemu-devel] [PATCH v2 2/3] memory: Provide an equality function for MemoryRegionSections Dr. David Alan Gilbert (git)
2019-09-25 14:30   ` [PULL " Michael S. Tsirkin
2019-08-14 17:55 ` Dr. David Alan Gilbert (git) [this message]
2019-09-25 14:30   ` [PULL 3/3] vhost: Fix memory region section comparison Michael S. Tsirkin
2019-08-15  2:16 ` [Qemu-devel] [PATCH v2 0/3] Fix MemoryRegionSection alignment and comparison no-reply
2019-09-25 14:30 [PULL 0/3] vhost: fixes Michael S. Tsirkin
2019-09-27 10:10 ` Peter Maydell

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