Re: [Qemu-devel] [PATCH v3 06/10] virtio: handle virtqueue_get_avail_bytes() errors

[Cornelia Huck]

On Tue, 12 Apr 2016 14:25:30 +0100
Stefan Hajnoczi  wrote:

> If the vring is invalid, tell the caller no bytes are available and mark
> the device broken.
> 
> Signed-off-by: Stefan Hajnoczi 
> ---
>  hw/virtio/virtio.c | 17 +++--
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 

> @@ -449,6 +449,11 @@ done:
>  if (out_bytes) {
>  *out_bytes = out_total;
>  }
> +return;
> +
> +err:
> +in_total = out_total = 0;
> +goto done;

This jumping around looks a bit weird, but I don't have any better idea.

>  }
> 
>  int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,

Reviewed-by: Cornelia Huck 

[Qemu-devel] [PATCH v3 06/10] virtio: handle virtqueue_get_avail_bytes() errors

[Stefan Hajnoczi]

If the vring is invalid, tell the caller no bytes are available and mark
the device broken.

Signed-off-by: Stefan Hajnoczi 
---
 hw/virtio/virtio.c | 17 +++--
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 0c0d333..48f759e 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -402,14 +402,14 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned 
int *in_bytes,
 
 if (desc.flags & VRING_DESC_F_INDIRECT) {
 if (desc.len % sizeof(VRingDesc)) {
-error_report("Invalid size for indirect buffer table");
-exit(1);
+virtio_error(vdev, "Invalid size for indirect buffer table");
+goto err;
 }
 
 /* If we've got too many, that implies a descriptor loop. */
 if (num_bufs >= max) {
-error_report("Looped descriptor");
-exit(1);
+virtio_error(vdev, "Looped descriptor");
+goto err;
 }
 
 /* loop over the indirect descriptor table */
@@ -423,8 +423,8 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int 
*in_bytes,
 do {
 /* If we've got too many, that implies a descriptor loop. */
 if (++num_bufs > max) {
-error_report("Looped descriptor");
-exit(1);
+virtio_error(vdev, "Looped descriptor");
+goto err;
 }
 
 if (desc.flags & VRING_DESC_F_WRITE) {
@@ -449,6 +449,11 @@ done:
 if (out_bytes) {
 *out_bytes = out_total;
 }
+return;
+
+err:
+in_total = out_total = 0;
+goto done;
 }
 
 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
-- 
2.5.5