[PULL 39/39] vhost-user-blk: Fail gracefully on too large queue size

[Kevin Wolf <kwolf@redhat.com>]

virtio_add_queue() aborts when queue_size > VIRTQUEUE_MAX_SIZE, so
vhost_user_blk_device_realize() should check this before calling it.

Simple reproducer:

qemu-system-x86_64 \
    -chardev null,id=foo \
    -device vhost-user-blk-pci,queue-size=4096,chardev=foo

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1935014
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210413165654.50810-1-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/block/vhost-user-blk.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 0b5b9d44cd..f5e9682703 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -467,6 +467,11 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
         error_setg(errp, "vhost-user-blk: queue size must be non-zero");
         return;
     }
+    if (s->queue_size > VIRTQUEUE_MAX_SIZE) {
+        error_setg(errp, "vhost-user-blk: queue size must not exceed %d",
+                   VIRTQUEUE_MAX_SIZE);
+        return;
+    }
 
     if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) {
         return;
-- 
2.30.2