2015-07-10 14:05, Xie, Huawei: > Thomas: > Could we roll back that commit or apply Changchun's patch?
It is waiting an agreement with Changchun, symbolized by an Acked-by: > On 7/1/2015 11:53 PM, Xie, Huawei wrote: > > On 7/1/2015 3:49 PM, Ouyang Changchun wrote: > >> This commit breaks virtio basic packets rx functionality: > >> d78deadae4dca240e85054bf2d604a801676becc > >> > >> The QEMU use 256 as default vring size, also use this default value to > >> calculate the virtio > >> avail ring base address and used ring base address, and vhost in the > >> backend use the ring base > >> address to do packet IO. > >> > >> Virtio spec also says the queue size in PCI configuration is read-only, so > >> virtio front end > >> can't change it. just need use the read-only value to allocate space for > >> vring and calculate the > >> avail and used ring base address. Otherwise, the avail and used ring base > >> address will be different > >> between host and guest, accordingly, packet IO can't work normally. > > virtio driver could still use the vq_size to initialize avail ring and > > use ring so that they still have the same base address. > > The other issue is vhost use index & (vq->size -1) to index the ring. > > > > > > Thomas: > > This fix works but introduces slight change with original code. Could we > > just rollback that commit? > > > > d78deadae4dca240e85054bf2d604a801676becc > > > > > >> Signed-off-by: Changchun Ouyang <changchun.ouyang at intel.com> > >> --- > >> drivers/net/virtio/virtio_ethdev.c | 14 +++----------- > >> 1 file changed, 3 insertions(+), 11 deletions(-)
