From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54677) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajLm0-0001ci-A7 for qemu-devel@nongnu.org; Fri, 25 Mar 2016 03:03:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ajLlx-0004bK-Kh for qemu-devel@nongnu.org; Fri, 25 Mar 2016 03:03:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45582) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajLlx-0004bG-F4 for qemu-devel@nongnu.org; Fri, 25 Mar 2016 03:03:05 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id 161FF164C95 for ; Fri, 25 Mar 2016 07:03:05 +0000 (UTC) Date: Fri, 25 Mar 2016 15:03:03 +0800 From: Fam Zheng Message-ID: <20160325070303.GH20431@ad.usersys.redhat.com> References: <1458842214-11450-1-git-send-email-stefanha@redhat.com> <1458842214-11450-7-git-send-email-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1458842214-11450-7-git-send-email-stefanha@redhat.com> Subject: Re: [Qemu-devel] [RFC 6/7] virtio: handle virtqueue_num_heads() errors List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" On Thu, 03/24 17:56, Stefan Hajnoczi wrote: > If the index avail ring index is bogus virtqueue_num_heads() must return s/index avail/avail/ ? > -EINVAL. > > The only caller is virtqueue_get_avail_bytes(). Return saying no bytes > are available when virtqueue_num_heads() fails. > > Signed-off-by: Stefan Hajnoczi > --- > hw/virtio/virtio.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index f845df2..525af8b 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -320,9 +320,9 @@ static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx) > > /* Check it isn't doing very strange things with descriptor numbers. */ > if (num_heads > vq->vring.num) { > - error_report("Guest moved used index from %u to %u", > + virtio_error(vq->vdev, "Guest moved used index from %u to %u", > idx, vq->shadow_avail_idx); > - exit(1); > + return -EINVAL; > } > /* On success, callers read a descriptor at vq->last_avail_idx. > * Make sure descriptor read does not bypass avail index read. */ > @@ -390,7 +390,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, > idx = vq->last_avail_idx; > > total_bufs = in_total = out_total = 0; > - while (virtqueue_num_heads(vq, idx)) { > + while ((rc = virtqueue_num_heads(vq, idx)) > 0) { > VirtIODevice *vdev = vq->vdev; > unsigned int max, num_bufs, indirect = 0; > VRingDesc desc; > @@ -451,6 +451,11 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, > else > total_bufs++; > } > + > + if (rc < 0) { > + goto err; > + } > + > done: > if (in_bytes) { > *in_bytes = in_total; > -- > 2.5.5 >