From: John Levon <[email protected]>
It is semantically valid for a VFIO device to increase the number of
regions after initialization. In this case, we'd attempt to check for
cached region info past the size of the ->reginfo array. Check for the
region index and skip the cache in these cases.
This also works around some VGPU use cases which appear to be a bug,
where VFIO_DEVICE_QUERY_GFX_PLANE returns a region index beyond the
reported ->num_regions.
Fixes: 95cdb024 ("vfio: add region info cache")
Signed-off-by: John Levon <[email protected]>
Reviewed-by: Cédric Le Goater <[email protected]>
Reviewed-by: Alex Williamson <[email protected]>
Link:
https://lore.kernel.org/qemu-devel/[email protected]
Signed-off-by: Cédric Le Goater <[email protected]>
(cherry picked from commit ecbe424a63c9f860a901d6a4a75724b046abd796)
Signed-off-by: Cédric Le Goater <[email protected]>
Signed-off-by: Michael Tokarev <[email protected]>
diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index 0b459c0f7c..7ebf41c95e 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -205,10 +205,19 @@ int vfio_device_get_region_info(VFIODevice *vbasedev, int
index,
int fd = -1;
int ret;
- /* check cache */
- if (vbasedev->reginfo[index] != NULL) {
- *info = vbasedev->reginfo[index];
- return 0;
+ /*
+ * We only set up the region info cache for the initial number of regions.
+ *
+ * Since a VFIO device may later increase the number of regions then use
+ * such regions with an index past ->num_initial_regions, don't attempt to
+ * use the info cache in those cases.
+ */
+ if (index < vbasedev->num_initial_regions) {
+ /* check cache */
+ if (vbasedev->reginfo[index] != NULL) {
+ *info = vbasedev->reginfo[index];
+ return 0;
+ }
}
*info = g_malloc0(argsz);
@@ -236,10 +245,12 @@ retry:
goto retry;
}
- /* fill cache */
- vbasedev->reginfo[index] = *info;
- if (vbasedev->region_fds != NULL) {
- vbasedev->region_fds[index] = fd;
+ if (index < vbasedev->num_initial_regions) {
+ /* fill cache */
+ vbasedev->reginfo[index] = *info;
+ if (vbasedev->region_fds != NULL) {
+ vbasedev->region_fds[index] = fd;
+ }
}
return 0;
--
2.47.3
