Re: [Qemu-devel] [PATCH 0/2] virtio len fixes for qemu.

[Fam Zheng]

On Wed, 03/11 07:19, Michael S. Tsirkin wrote:
> On Wed, Mar 11, 2015 at 04:29:30PM +1030, Rusty Russell wrote:
> > The virtio 'used' ring describes descriptors which have been used.  It
> > also says how many bytes have been written to the ring.  For some cases,
> > this value is ignored by Linux guests, thus errors have not been noticed.
> > I was working on increasing the checking in Linux when I noticed this
> > behaviour.
> > 
> > The first patch changes the 'len' formal parameter name to 'len_written' to
> > make the API clearer, and adds an assert(). The second fixes block writes.
> > 
> > Cheers,
> > Rusty.
> > PS.  It's based on MST's virtio-1.0 tree, but should be easily ported.
> 
> Thanks, this applies to current master without issues.
> However, I think  it's best to apply patch 2, then patch 1,
> to avoid triggering errors when bisecting.

I'm seeing a make check failure. If this is a false alarm, the test should be
fixed too.

---

qemu-system-x86_64: /var/tmp/patchew-test/git/hw/virtio/virtio.c:254: 
virtqueue_fill: Assertion `len_written <= tot_wlen' failed.
Broken pipe
GTester: last random seed: R02Se642bf29179ebe0c4a92eb02cc488dd8
[vmxnet3][WR][vmxnet3_peer_has_vnet_hdr]: Peer has no virtio extension. Task 
offloads will be emulated.
make: *** [check-qtest-x86_64] Error 1