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-sta...@nongnu.org
Suggested-by: Alexander Bulekov <alx...@bu.edu>
Signed-off-by: Philippe Mathieu-Daudé <phi...@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;
  }