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(-) > >
