Messages in this thread | | | Subject | Re: [RFC v3 0/5] virtio: support packed ring | From | Jason Wang <> | Date | Fri, 27 Apr 2018 14:17:51 +0800 |
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On 2018年04月27日 12:18, Michael S. Tsirkin wrote: > On Fri, Apr 27, 2018 at 11:56:05AM +0800, Jason Wang wrote: >> On 2018年04月25日 13:15, Tiwei Bie wrote: >>> Hello everyone, >>> >>> This RFC implements packed ring support in virtio driver. >>> >>> Some simple functional tests have been done with Jason's >>> packed ring implementation in vhost: >>> >>> https://lkml.org/lkml/2018/4/23/12 >>> >>> Both of ping and netperf worked as expected (with EVENT_IDX >>> disabled). But there are below known issues: >>> >>> 1. Reloading the guest driver will break the Tx/Rx; >> Will have a look at this issue. >> >>> 2. Zeroing the flags when detaching a used desc will >>> break the guest -> host path. >> I still think zeroing flags is unnecessary or even a bug. At host, I track >> last observed avail wrap counter and detect avail like (what is suggested in >> the example code in the spec): >> >> static bool desc_is_avail(struct vhost_virtqueue *vq, __virtio16 flags) >> { >> bool avail = flags & cpu_to_vhost16(vq, DESC_AVAIL); >> >> return avail == vq->avail_wrap_counter; >> } >> >> So zeroing wrap can not work with this obviously. >> >> Thanks > I agree. I think what one should do is flip the available bit. >
But is this flipping a must?
Thanks
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