Re: [PATCH-for-9.0 3/4] hw/char/virtio-serial-bus: Protect from DMA re-entrancy bugs

[Philippe Mathieu-Daudé]

On 4/4/24 21:13, Philippe Mathieu-Daudé wrote:
> Replace qemu_bh_new_guarded() by virtio_bh_new_guarded()
> so the bus and device use the same guard. Otherwise the
> DMA-reentrancy protection can be bypassed.
>
> Cc: qemu-stable@nongnu.org
> Suggested-by: Alexander Bulekov <alxndr@bu.edu>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>   hw/char/virtio-serial-bus.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
> index 016aba6374..cd0e3a11f7 100644
> --- a/hw/char/virtio-serial-bus.c
> +++ b/hw/char/virtio-serial-bus.c
> @@ -985,8 +985,7 @@ static void virtser_port_device_realize(DeviceState *dev, 
> Error **errp)
>           return;
>       }
>   
> -    port->bh = qemu_bh_new_guarded(flush_queued_data_bh, port,
> -                                   &dev->mem_reentrancy_guard);
> +    port->bh = virtio_bh_new_guarded(vdev, flush_queued_data_bh, port);

Missing:
-- >8 --
-    port->bh = virtio_bh_new_guarded(vdev, flush_queued_data_bh, port);
+    port->bh = virtio_bh_new_guarded(VIRTIO_DEVICE(dev),
+                                     flush_queued_data_bh, port);
---

>       port->elem = NULL;
>   }
>