> -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Thomas Monjalon > Sent: Friday, July 10, 2015 10:12 PM > To: Xie, Huawei > Cc: dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH] virtio: fix the vq size issue > > 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:
I think applying this patch is better than rolling back the previous commit, Besides fixing the issue, this patch also removes an unnecessary assigning inside that function. > > > > 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(-)
