Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-07 Thread Jason Wang
On 2020/5/6 下午5:46, Michael S. Tsirkin wrote: There are a lot of unanswered questions on how this will be implemented. Thus, I cannot layout how we are going to leverage this info yet, but your patch are killing this info, which IHMO is going in the wrong direction. I can copy vnet header ahea

Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-07 Thread Jason Wang
On 2020/5/6 下午5:54, Michael S. Tsirkin wrote: On Wed, May 06, 2020 at 04:19:40PM +0800, Jason Wang wrote: On 2020/5/6 下午3:53, Michael S. Tsirkin wrote: On Wed, May 06, 2020 at 02:16:32PM +0800, Jason Wang wrote: We tried to reserve space for vnet header before xdp.data_hard_start. But this i

Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-06 Thread Michael S. Tsirkin
On Wed, May 06, 2020 at 04:19:40PM +0800, Jason Wang wrote: > > On 2020/5/6 下午3:53, Michael S. Tsirkin wrote: > > On Wed, May 06, 2020 at 02:16:32PM +0800, Jason Wang wrote: > > > We tried to reserve space for vnet header before > > > xdp.data_hard_start. But this is useless since the packet could

Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-06 Thread Michael S. Tsirkin
On Wed, May 06, 2020 at 04:34:36PM +0800, Jason Wang wrote: > > On 2020/5/6 下午4:21, Jesper Dangaard Brouer wrote: > > On Wed, 6 May 2020 14:16:32 +0800 > > Jason Wang wrote: > > > > > We tried to reserve space for vnet header before > > > xdp.data_hard_start. But this is useless since the packe

Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-06 Thread Jason Wang
On 2020/5/6 下午4:21, Jesper Dangaard Brouer wrote: On Wed, 6 May 2020 14:16:32 +0800 Jason Wang wrote: We tried to reserve space for vnet header before xdp.data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the header

Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-06 Thread Jesper Dangaard Brouer
On Wed, 6 May 2020 14:16:32 +0800 Jason Wang wrote: > We tried to reserve space for vnet header before > xdp.data_hard_start. But this is useless since the packet could be > modified by XDP which may invalidate the information stored in the > header and IMHO above statements are wrong. XDP cann

Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-06 Thread Jason Wang
On 2020/5/6 下午3:53, Michael S. Tsirkin wrote: On Wed, May 06, 2020 at 02:16:32PM +0800, Jason Wang wrote: We tried to reserve space for vnet header before xdp.data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the heade

Re: [PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-06 Thread Michael S. Tsirkin
On Wed, May 06, 2020 at 02:16:32PM +0800, Jason Wang wrote: > We tried to reserve space for vnet header before > xdp.data_hard_start. But this is useless since the packet could be > modified by XDP which may invalidate the information stored in the > header and there's no way for XDP to know the ex

[PATCH net-next 1/2] virtio-net: don't reserve space for vnet header for XDP

2020-05-05 Thread Jason Wang
We tried to reserve space for vnet header before xdp.data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the header and there's no way for XDP to know the existence of the vnet header currently. So let's just not reserve spa