Re: [PATCH 2/5] virtio-iommu: Implement RESV_MEM probe request

[Peter Xu <peterx@redhat.com>]

Hi, Eric,

On Thu, May 07, 2020 at 04:31:58PM +0200, Eric Auger wrote:

[...]

> @@ -452,17 +520,33 @@ static void virtio_iommu_handle_command(VirtIODevice *vdev, VirtQueue *vq)
>          case VIRTIO_IOMMU_T_UNMAP:
>              tail.status = virtio_iommu_handle_unmap(s, iov, iov_cnt);
>              break;
> +        case VIRTIO_IOMMU_T_PROBE:
> +        {
> +            struct virtio_iommu_req_tail *ptail;
> +            uint8_t *buf = g_malloc0(s->config.probe_size + sizeof(tail));
> +
> +            ptail = (struct virtio_iommu_req_tail *)
> +                        (buf + s->config.probe_size);
> +            ptail->status = virtio_iommu_handle_probe(s, iov, iov_cnt, buf);
> +
> +            sz = iov_from_buf(elem->in_sg, elem->in_num, 0,
> +                              buf, s->config.probe_size + sizeof(tail));
> +            g_free(buf);
> +            assert(sz == s->config.probe_size + sizeof(tail));
> +            goto push;
> +        }
>          default:
>              tail.status = VIRTIO_IOMMU_S_UNSUPP;
>          }
> -        qemu_mutex_unlock(&s->mutex);
>  
>  out:
>          sz = iov_from_buf(elem->in_sg, elem->in_num, 0,
>                            &tail, sizeof(tail));
>          assert(sz == sizeof(tail));
>  
> -        virtqueue_push(vq, elem, sizeof(tail));
> +push:
> +        qemu_mutex_unlock(&s->mutex);

I think we can't move this unlock to here because otherwise "goto out" could
potentially try to unlock it without locked first.  Thanks,

> +        virtqueue_push(vq, elem, sz);
>          virtio_notify(vdev, vq);
>          g_free(elem);
>      }

-- 
Peter Xu