similar to: [PATCH net v1] virtio_net: bugfix overflow inside xdp_linearize_page()

Here we copy the data from the original buf to the new page. But we not check that it may be overflow. As long as the size received(including vnethdr) is greater than 3840 (PAGE_SIZE -VIRTIO_XDP_HEADROOM). Then the memcpy will overflow. And this is completely possible, as long as the MTU is large, such as 4096. In our test environment, this will cause crash. Since crash is caused by the written

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

Hi: This series tries to re-enable XDP_REDIRECT for mergeable buffer which was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). Main concerns are: - not enough tailroom was reserved which breaks cpumap - complex logic like EWMA and linearizing during XDP processing Fix those by: - reserve enough tailroom during refill - disable EWMA

Hi: This series tries to re-enable XDP_REDIRECT for mergeable buffer which was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). Main concerns are: - not enough tailroom was reserved which breaks cpumap - complex logic like EWMA and linearizing during XDP processing Fix those by: - reserve enough tailroom during refill - disable EWMA

On Fri, Mar 02, 2018 at 05:29:14PM +0800, Jason Wang wrote: > XDP_REDIRECT support for mergeable buffer was removed since commit > 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() > case"). This is because we don't reserve enough tailroom for struct > skb_shared_info which breaks XDP assumption. So this patch fixes this > by reserving enough

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. So this patch fixes this by reserving enough tailroom and using fixed size of rx buffer. Signed-off-by: Jason Wang <jasowang at

On Mon, Jul 17, 2017 at 08:44:00PM +0800, Jason Wang wrote: > We used to reset during XDP set, the main reason is we need allocate > extra headroom for header adjustment but there's no way to know the > headroom of exist receive buffer. This works buy maybe complex and may > cause the network down for a while which is bad for user > experience. So this patch tries to avoid this

On Mon, Jul 17, 2017 at 08:44:00PM +0800, Jason Wang wrote: > We used to reset during XDP set, the main reason is we need allocate > extra headroom for header adjustment but there's no way to know the > headroom of exist receive buffer. This works buy maybe complex and may > cause the network down for a while which is bad for user > experience. So this patch tries to avoid this

We used to do data copy through xdp_linearize_page() for the buffer without sufficient headroom, it brings extra complexity without helping for the performance. So this patch remove it and switch to use generic XDP routine to handle this case. Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 93 ++++++------------------------------------------ 1 file

We used to reset during XDP set, the main reason is we need allocate extra headroom for header adjustment but there's no way to know the headroom of exist receive buffer. This works buy maybe complex and may cause the network down for a while which is bad for user experience. So this patch tries to avoid this by: - packing headroom into receive buffer ctx - check the headroom during XDP, and

Separating the logic of preparation for xdp from receive_mergeable. The purpose of this is to simplify the logic of execution of XDP. The main logic here is that when headroom is insufficient, we need to allocate a new page and calculate offset. It should be noted that if there is new page, the variable page will refer to the new page. Signed-off-by: Xuan Zhuo <xuanzhuo at

? 2023/3/28 20:04, Xuan Zhuo ??: > Separating the logic of preparation for xdp from receive_mergeable. > > The purpose of this is to simplify the logic of execution of XDP. > > The main logic here is that when headroom is insufficient, we need to > allocate a new page and calculate offset. It should be noted that if > there is new page, the variable page will refer to the new

On Thu, Mar 01, 2018 at 11:19:04AM +0800, Jason Wang wrote: > XDP_REDIRECT support for mergeable buffer was removed since commit > 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() > case"). This is because we don't reserve enough tailroom for struct > skb_shared_info which breaks XDP assumption. Other complaints are, the > complex linearize logic

On 2018?03?01? 18:35, Jesper Dangaard Brouer wrote: > On Thu, 1 Mar 2018 17:23:37 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> On 2018?03?01? 17:10, Jesper Dangaard Brouer wrote: >>> On Thu, 1 Mar 2018 11:19:03 +0800 >>> Jason Wang <jasowang at redhat.com> wrote: >>> >>>> This series tries to re-enable XDP_REDIRECT

On 2018?03?01? 18:35, Jesper Dangaard Brouer wrote: > On Thu, 1 Mar 2018 17:23:37 +0800 > Jason Wang <jasowang at redhat.com> wrote: > >> On 2018?03?01? 17:10, Jesper Dangaard Brouer wrote: >>> On Thu, 1 Mar 2018 11:19:03 +0800 >>> Jason Wang <jasowang at redhat.com> wrote: >>> >>>> This series tries to re-enable XDP_REDIRECT

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as the ctx virtio-net: pack headroom into ctx for mergeable buffer virtio-net: switch to use new ctx API for small buffer virtio-net: do not reset during XDP set virtio-net: switch off offloads

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as the ctx virtio-net: pack headroom into ctx for mergeable buffer virtio-net: switch to use new ctx API for small buffer virtio-net: do not reset during XDP set virtio-net: switch off offloads

XDP_REDIRECT support for mergeable buffer was removed since commit 7324f5399b06 ("virtio_net: disable XDP_REDIRECT in receive_mergeable() case"). This is because we don't reserve enough tailroom for struct skb_shared_info which breaks XDP assumption. Other complaints are, the complex linearize logic and EWMA estimation may increase the possibility of linearizing. Signed-off-by: