@@ -789,6 +789,13 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
return;
}
+ if (virtio_has_feature(s->host_features, VIRTIO_BALLOON_F_FREE_PAGE_HINT) &&
+ !s->iothread) {
+ error_setg(errp, "'free-page-hint' requires 'iothread' to be set");
+ virtio_cleanup(vdev);
+ return;
+ }
+
s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
@@ -797,24 +804,11 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE,
virtio_balloon_handle_free_page_vq);
- s->free_page_report_status = FREE_PAGE_REPORT_S_STOP;
- s->free_page_report_cmd_id =
- VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN;
- s->free_page_report_notify.notify =
- virtio_balloon_free_page_report_notify;
precopy_add_notifier(&s->free_page_report_notify);
- if (s->iothread) {
- object_ref(OBJECT(s->iothread));
- s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread),
- virtio_ballloon_get_free_page_hints, s);
- qemu_mutex_init(&s->free_page_lock);
- qemu_cond_init(&s->free_page_cond);
- s->block_iothread = false;
- } else {
- /* Simply disable this feature if the iothread wasn't created. */
- s->host_features &= ~(1 << VIRTIO_BALLOON_F_FREE_PAGE_HINT);
- virtio_error(vdev, "iothread is missing");
- }
+
+ object_ref(OBJECT(s->iothread));
+ s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread),
+ virtio_ballloon_get_free_page_hints, s);
}
reset_stats(s);
}
@@ -892,6 +886,11 @@ static void virtio_balloon_instance_init(Object *obj)
{
VirtIOBalloon *s = VIRTIO_BALLOON(obj);
+ qemu_mutex_init(&s->free_page_lock);
+ qemu_cond_init(&s->free_page_cond);
+ s->free_page_report_cmd_id = VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN;
+ s->free_page_report_notify.notify = virtio_balloon_free_page_report_notify;
+
object_property_add(obj, "guest-stats", "guest statistics",
balloon_stats_get_all, NULL, NULL, s);
In case we don't have an iothread, we mark the feature as abscent but still add the queue. 'free_page_bh' remains set to NULL. qemu-system-i386 \ -M microvm \ -nographic \ -device virtio-balloon-device,free-page-hint=true \ -nographic \ -display none \ -monitor none \ -serial none \ -qtest stdio Doing a "write 0xc0000e30 0x24 0x030000000300000003000000030000000300000003000000030000000300000003000000" We will trigger a SEGFAULT. Let's move the check and bail out. While at it, move the static initializations to instance_init(). free_page_report_status and block_iothread are implicitly set to the right values (0/false) already, so drop the initialization. Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") Reported-by: Alexander Bulekov <alxndr@bu.edu> Cc: qemu-stable@nongnu.org Cc: Wei Wang <wei.w.wang@intel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Philippe Mathieu-Daudé <philmd@redhat.com> Cc: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by: David Hildenbrand <david@redhat.com> --- hw/virtio/virtio-balloon.c | 33 ++++++++++++++++----------------- 1 file changed, 16 insertions(+), 17 deletions(-)