similar to: [PATCH V2 0/4] Prevent vhost kthread from hogging CPU

Hi: This series try to prvernt a guest triggerable CPU hogging through vhost kthread. This is done by introducing and checking the weight after each requrest. The patch has been tested with reproducer of vsock and virtio-net. Only compile test is done for vhost-scsi. Please review. This addresses CVE-2019-3900. Jason Wang (4): vhost: introduce vhost_exceeds_weight() vhost_net: fix possible

When the rx buffer is too small for a packet, we will discard the vq descriptor and retry it for the next packet: while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk, &busyloop_intr))) { ... /* On overrun, truncate and discard */ if (unlikely(headcount > UIO_MAXIOV)) { iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); err = sock->ops->recvmsg(sock,

When the rx buffer is too small for a packet, we will discard the vq descriptor and retry it for the next packet: while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk, &busyloop_intr))) { ... /* On overrun, truncate and discard */ if (unlikely(headcount > UIO_MAXIOV)) { iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); err = sock->ops->recvmsg(sock,

On 2019/4/26 ??1:52, Michael S. Tsirkin wrote: > On Thu, Apr 25, 2019 at 03:33:19AM -0400, Jason Wang wrote: >> When the rx buffer is too small for a packet, we will discard the vq >> descriptor and retry it for the next packet: >> >> while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk, >> &busyloop_intr))) { >> ... >> /* On

On 2019/4/26 ??1:52, Michael S. Tsirkin wrote: > On Thu, Apr 25, 2019 at 03:33:19AM -0400, Jason Wang wrote: >> When the rx buffer is too small for a packet, we will discard the vq >> descriptor and retry it for the next packet: >> >> while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk, >> &busyloop_intr))) { >> ... >> /* On

On Sun, May 05, 2019 at 12:20:24PM +0800, Jason Wang wrote: > > On 2019/4/26 ??3:35, Jason Wang wrote: > > > > On 2019/4/26 ??1:52, Michael S. Tsirkin wrote: > > > On Thu, Apr 25, 2019 at 03:33:19AM -0400, Jason Wang wrote: > > > > When the rx buffer is too small for a packet, we will discard the vq > > > > descriptor and retry it for the next

On Sun, May 05, 2019 at 12:20:24PM +0800, Jason Wang wrote: > > On 2019/4/26 ??3:35, Jason Wang wrote: > > > > On 2019/4/26 ??1:52, Michael S. Tsirkin wrote: > > > On Thu, Apr 25, 2019 at 03:33:19AM -0400, Jason Wang wrote: > > > > When the rx buffer is too small for a packet, we will discard the vq > > > > descriptor and retry it for the next

Hi: This series implement batch updating of used ring for TX. This help to reduce the cache contention on used ring. The idea is first split datacopy path from zerocopy, and do only batching for datacopy. This is because zercopy had already supported its own batching. TX PPS was increased 25.8% and Netperf TCP does not show obvious differences. The split of datapath will also be helpful for

Hi: This series implement batch updating of used ring for TX. This help to reduce the cache contention on used ring. The idea is first split datacopy path from zerocopy, and do only batching for datacopy. This is because zercopy had already supported its own batching. TX PPS was increased 25.8% and Netperf TCP does not show obvious differences. The split of datapath will also be helpful for

This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that converting to iov later. Used ring is similar: we fetch into an independent struct first, convert that to IOV later. The point is that we have a tight loop that fetches descriptors, which is good for cache utilization. This will

We let the specifics of the ring format seep through to vhost API callers - mostly because there was only one format so it was hard to imagine what an independent API would look like. Now that there's an alternative in form of the packed ring, it's easier to see the issues, and fixing them is perhaps the cleanest way to add support for more formats. This patchset does this by indtroducing

On 2020/6/2 ??9:06, Michael S. Tsirkin wrote: > Convert vhost net to use the new format-agnostic API. > In particular, don't poke at vq internals such as the > heads array. > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > drivers/vhost/net.c | 153 +++++++++++++++++++++++--------------------- > 1 file changed, 81 insertions(+), 72 deletions(-)

This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that converting to iov later. Used ring is similar: we fetch into an independent struct first, convert that to IOV later. The point is that we have a tight loop that fetches descriptors, which is good for cache utilization. This will

Hi all: We do not support XDP batching for TUN since it can only receive one packet a time from vhost_net. This series tries to remove this limitation by: - introduce a TUN specific msg_control that can hold a pointer to an array of XDP buffs - try copy and build XDP buff in vhost_net - store XDP buffs in an array and submit them once for every N packets from vhost_net - since TUN can only

This intentionally leaves "fixup" changes separate - hopefully that is enough to fix vhost-net crashes reported here, but it helps me keep track of what changed. I will naturally squash them later when we are done. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that

This intentionally leaves "fixup" changes separate - hopefully that is enough to fix vhost-net crashes reported here, but it helps me keep track of what changed. I will naturally squash them later when we are done. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that

Hi all: This series implements packed virtqueues which were described at [1]. In this version we try to address the performance regression saw by V2. The root cause is packed virtqueue need more times of userspace memory accesssing which turns out to be very expensive. Thanks to the help of 7f466032dc9e ("vhost: access vq metadata through kernel virtual address"), such overhead cold be

Hi all: This series implements packed virtqueues which were described at [1]. In this version we try to address the performance regression saw by V2. The root cause is packed virtqueue need more times of userspace memory accesssing which turns out to be very expensive. Thanks to the help of 7f466032dc9e ("vhost: access vq metadata through kernel virtual address"), such overhead cold be

On Thu, Sep 06, 2018 at 12:05:26PM +0800, Jason Wang wrote: > This patch implements XDP batching for vhost_net. The idea is first to > try to do userspace copy and build XDP buff directly in vhost. Instead > of submitting the packet immediately, vhost_net will batch them in an > array and submit every 64 (VHOST_NET_BATCH) packets to the under layer > sockets through msg_control of

On Thu, Sep 06, 2018 at 12:05:26PM +0800, Jason Wang wrote: > This patch implements XDP batching for vhost_net. The idea is first to > try to do userspace copy and build XDP buff directly in vhost. Instead > of submitting the packet immediately, vhost_net will batch them in an > array and submit every 64 (VHOST_NET_BATCH) packets to the under layer > sockets through msg_control of