On 9/21/20 1:34 PM, Stefan Hajnoczi wrote:
> vu_panic() is not guaranteed to exit the program. Return early when
> errors are encountered.
>
> Note that libvhost-user does not have an "unmap" operation for mapped
> descriptors. Therefore it is correct to return without explicit cleanup.
>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> ---
> contrib/libvhost-user/libvhost-user.c | 27 +++++++++++++++++----------
> 1 file changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/contrib/libvhost-user/libvhost-user.c
> b/contrib/libvhost-user/libvhost-user.c
> index 53f16bdf08..27626e629a 100644
> --- a/contrib/libvhost-user/libvhost-user.c
> +++ b/contrib/libvhost-user/libvhost-user.c
> @@ -2407,7 +2407,7 @@ vu_queue_set_notification(VuDev *dev, VuVirtq *vq, int
> enable)
> }
> }
>
> -static void
> +static bool
> virtqueue_map_desc(VuDev *dev,
> unsigned int *p_num_sg, struct iovec *iov,
> unsigned int max_num_sg, bool is_write,
> @@ -2419,7 +2419,7 @@ virtqueue_map_desc(VuDev *dev,
>
> if (!sz) {
> vu_panic(dev, "virtio: zero sized buffers are not allowed");
> - return;
> + return false;
> }
>
> while (sz) {
> @@ -2427,13 +2427,13 @@ virtqueue_map_desc(VuDev *dev,
>
> if (num_sg == max_num_sg) {
> vu_panic(dev, "virtio: too many descriptors in indirect table");
> - return;
> + return false;
> }
>
> iov[num_sg].iov_base = vu_gpa_to_va(dev, &len, pa);
> if (iov[num_sg].iov_base == NULL) {
> vu_panic(dev, "virtio: invalid address for buffers");
> - return;
> + return false;
> }
> iov[num_sg].iov_len = len;
> num_sg++;
> @@ -2442,6 +2442,7 @@ virtqueue_map_desc(VuDev *dev,
> }
>
> *p_num_sg = num_sg;
> + return true;
> }
Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
>
> static void *
> @@ -2479,6 +2480,7 @@ vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned int
> idx, size_t sz)
> if (desc[i].flags & VRING_DESC_F_INDIRECT) {
> if (desc[i].len % sizeof(struct vring_desc)) {
> vu_panic(dev, "Invalid size for indirect buffer table");
> + return NULL;
> }
>
> /* loop over the indirect descriptor table */
> @@ -2506,22 +2508,27 @@ vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned
> int idx, size_t sz)
> /* Collect all the descriptors */
> do {
> if (desc[i].flags & VRING_DESC_F_WRITE) {
> - virtqueue_map_desc(dev, &in_num, iov + out_num,
> - VIRTQUEUE_MAX_SIZE - out_num, true,
> - desc[i].addr, desc[i].len);
> + if (!virtqueue_map_desc(dev, &in_num, iov + out_num,
> + VIRTQUEUE_MAX_SIZE - out_num, true,
> + desc[i].addr, desc[i].len)) {
> + return NULL;
> + }
> } else {
> if (in_num) {
> vu_panic(dev, "Incorrect order for descriptors");
> return NULL;
> }
> - virtqueue_map_desc(dev, &out_num, iov,
> - VIRTQUEUE_MAX_SIZE, false,
> - desc[i].addr, desc[i].len);
> + if (!virtqueue_map_desc(dev, &out_num, iov,
> + VIRTQUEUE_MAX_SIZE, false,
> + desc[i].addr, desc[i].len)) {
> + return NULL;
> + }
> }
>
> /* If we've got too many, that implies a descriptor loop. */
> if ((in_num + out_num) > max) {
> vu_panic(dev, "Looped descriptor");
> + return NULL;
> }
> rc = virtqueue_read_next_desc(dev, desc, i, max, &i);
> } while (rc == VIRTQUEUE_READ_DESC_MORE);
>
