From: Prashant Bhole <prashantbhole.linux@gmail.com> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: "David S . Miller" <davem@davemloft.net>, Jason Wang <jasowang@redhat.com>, Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Jakub Kicinski <jakub.kicinski@netronome.com>, Jesper Dangaard Brouer <hawk@kernel.org>, John Fastabend <john.fastabend@gmail.com>, Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>, netdev@vger.kernel.org, qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: Re: [RFC net-next 15/18] virtio_net: implement XDP prog offload functionality Date: Thu, 28 Nov 2019 11:53:41 +0900 [thread overview] Message-ID: <73323055-3f8a-802d-87da-e8f61ef5cfb7@gmail.com> (raw) In-Reply-To: <20191127153253-mutt-send-email-mst@kernel.org> On 11/28/19 5:42 AM, Michael S. Tsirkin wrote: > On Tue, Nov 26, 2019 at 07:07:41PM +0900, Prashant Bhole wrote: >> From: Jason Wang <jasowang@redhat.com> >> >> This patch implements bpf_prog_offload_ops callbacks and adds handling >> for XDP_SETUP_PROG_HW. Handling of XDP_SETUP_PROG_HW involves setting >> up struct virtio_net_ctrl_ebpf_prog and appending program instructions >> to it. This control buffer is sent to Qemu with class >> VIRTIO_NET_CTRL_EBPF and command VIRTIO_NET_BPF_CMD_SET_OFFLOAD. >> The expected behavior from Qemu is that it should try to load the >> program in host os and report the status. > > That's not great e.g. for migration: different hosts might have > a different idea about what's allowed. > Device capabilities should be preferably exported through > feature bits or config space such that it's easy to > intercept and limit these as needed. These things are mentioned in the TODO section of cover letter. Having offload feature enabled should be a migration blocker. A feature bit in virtio for offloading capability needs to be added. > > Also, how are we going to handle e.g. endian-ness here? For now I feel we should block offloading in case of cross endian virtualization. Further to support cross endian-ness, the requests for offloading a map or program should include metadata such as BTF info. Qemu needs to handle the conversion. > >> >> It also adds restriction to have either driver or offloaded program >> at a time. > > I'm not sure I understand what does the above say. > virtnet_xdp_offload_check? > Please add code comments so we remember what to do and when. > >> This restriction can be removed later after proper testing. > > What kind of testing is missing here? This restriction mentioned above is about having multiple programs attached to the same device. It can be possible to have a program attached in driver mode and other in offload mode, but in current code only one mode at a time is supported because I wasn't aware whether bpf tooling supports the case. I will add a comment or remove the restriction in the next revision. > >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> Co-developed-by: Prashant Bhole <prashantbhole.linux@gmail.com> >> Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com> > > Any UAPI changes need to be copied to virtio-dev@lists.oasis-open.org > (subscriber only) list please. Sure. Thanks.
WARNING: multiple messages have this Message-ID (diff)
From: Prashant Bhole <prashantbhole.linux@gmail.com> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: Song Liu <songliubraving@fb.com>, Jakub Kicinski <jakub.kicinski@netronome.com>, Jesper Dangaard Brouer <hawk@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, qemu-devel@nongnu.org, netdev@vger.kernel.org, Jason Wang <jasowang@redhat.com>, John Fastabend <john.fastabend@gmail.com>, Alexei Starovoitov <ast@kernel.org>, Martin KaFai Lau <kafai@fb.com>, kvm@vger.kernel.org, Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>, "David S . Miller" <davem@davemloft.net> Subject: Re: [RFC net-next 15/18] virtio_net: implement XDP prog offload functionality Date: Thu, 28 Nov 2019 11:53:41 +0900 [thread overview] Message-ID: <73323055-3f8a-802d-87da-e8f61ef5cfb7@gmail.com> (raw) In-Reply-To: <20191127153253-mutt-send-email-mst@kernel.org> On 11/28/19 5:42 AM, Michael S. Tsirkin wrote: > On Tue, Nov 26, 2019 at 07:07:41PM +0900, Prashant Bhole wrote: >> From: Jason Wang <jasowang@redhat.com> >> >> This patch implements bpf_prog_offload_ops callbacks and adds handling >> for XDP_SETUP_PROG_HW. Handling of XDP_SETUP_PROG_HW involves setting >> up struct virtio_net_ctrl_ebpf_prog and appending program instructions >> to it. This control buffer is sent to Qemu with class >> VIRTIO_NET_CTRL_EBPF and command VIRTIO_NET_BPF_CMD_SET_OFFLOAD. >> The expected behavior from Qemu is that it should try to load the >> program in host os and report the status. > > That's not great e.g. for migration: different hosts might have > a different idea about what's allowed. > Device capabilities should be preferably exported through > feature bits or config space such that it's easy to > intercept and limit these as needed. These things are mentioned in the TODO section of cover letter. Having offload feature enabled should be a migration blocker. A feature bit in virtio for offloading capability needs to be added. > > Also, how are we going to handle e.g. endian-ness here? For now I feel we should block offloading in case of cross endian virtualization. Further to support cross endian-ness, the requests for offloading a map or program should include metadata such as BTF info. Qemu needs to handle the conversion. > >> >> It also adds restriction to have either driver or offloaded program >> at a time. > > I'm not sure I understand what does the above say. > virtnet_xdp_offload_check? > Please add code comments so we remember what to do and when. > >> This restriction can be removed later after proper testing. > > What kind of testing is missing here? This restriction mentioned above is about having multiple programs attached to the same device. It can be possible to have a program attached in driver mode and other in offload mode, but in current code only one mode at a time is supported because I wasn't aware whether bpf tooling supports the case. I will add a comment or remove the restriction in the next revision. > >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> Co-developed-by: Prashant Bhole <prashantbhole.linux@gmail.com> >> Signed-off-by: Prashant Bhole <prashantbhole.linux@gmail.com> > > Any UAPI changes need to be copied to virtio-dev@lists.oasis-open.org > (subscriber only) list please. Sure. Thanks.
next prev parent reply other threads:[~2019-11-28 2:54 UTC|newest] Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-26 10:07 [RFC net-next 00/18] virtio_net XDP offload Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 01/18] bpf: introduce bpf_prog_offload_verifier_setup() Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 02/18] net: core: rename netif_receive_generic_xdp() to do_generic_xdp_core() Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 03/18] net: core: export do_xdp_generic_core() Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 04/18] tuntap: check tun_msg_ctl type at necessary places Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 05/18] vhost_net: user tap recvmsg api to access ptr ring Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 06/18] tuntap: remove usage of ptr ring in vhost_net Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 07/18] tun: set offloaded xdp program Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-12-01 16:35 ` David Ahern 2019-12-01 16:35 ` David Ahern 2019-12-02 2:44 ` Jason Wang 2019-12-02 2:44 ` Jason Wang 2019-12-01 16:45 ` David Ahern 2019-12-01 16:45 ` David Ahern 2019-12-02 2:47 ` Jason Wang 2019-12-02 2:47 ` Jason Wang 2019-12-09 0:24 ` Prashant Bhole 2019-12-09 0:24 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 08/18] tun: run offloaded XDP program in Tx path Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-12-01 16:39 ` David Ahern 2019-12-01 16:39 ` David Ahern 2019-12-01 20:56 ` David Miller 2019-12-01 20:56 ` David Miller 2019-12-01 21:40 ` Michael S. Tsirkin 2019-12-01 21:40 ` Michael S. Tsirkin 2019-12-01 21:54 ` David Miller 2019-12-01 21:54 ` David Miller 2019-12-02 2:56 ` Jason Wang 2019-12-02 2:56 ` Jason Wang 2019-12-02 2:45 ` Jason Wang 2019-12-02 2:45 ` Jason Wang 2019-11-26 10:07 ` [RFC net-next 09/18] tun: add a way to inject Tx path packet into Rx path Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 10/18] tun: handle XDP_TX action of offloaded program Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 11/18] tun: run xdp prog when tun is read from file interface Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 12/18] virtio-net: store xdp_prog in device Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 13/18] virtio_net: use XDP attachment helpers Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 14/18] virtio_net: add XDP prog offload infrastructure Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 15/18] virtio_net: implement XDP prog offload functionality Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-27 20:42 ` Michael S. Tsirkin 2019-11-27 20:42 ` Michael S. Tsirkin 2019-11-28 2:53 ` Prashant Bhole [this message] 2019-11-28 2:53 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 16/18] bpf: export function __bpf_map_get Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 10:07 ` [RFC net-next 17/18] virtio_net: implment XDP map offload functionality Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 20:19 ` kbuild test robot 2019-11-26 10:07 ` [RFC net-next 18/18] virtio_net: restrict bpf helper calls from offloaded program Prashant Bhole 2019-11-26 10:07 ` Prashant Bhole 2019-11-26 20:35 ` [RFC net-next 00/18] virtio_net XDP offload Jakub Kicinski 2019-11-26 20:35 ` Jakub Kicinski 2019-11-27 2:59 ` Jason Wang 2019-11-27 2:59 ` Jason Wang 2019-11-27 19:49 ` Jakub Kicinski 2019-11-27 19:49 ` Jakub Kicinski 2019-11-28 3:41 ` Jason Wang 2019-11-28 3:41 ` Jason Wang 2019-11-27 20:32 ` Michael S. Tsirkin 2019-11-27 20:32 ` Michael S. Tsirkin 2019-11-27 23:40 ` Jakub Kicinski 2019-11-27 23:40 ` Jakub Kicinski 2019-12-02 15:29 ` Michael S. Tsirkin 2019-12-02 15:29 ` Michael S. Tsirkin 2019-11-28 3:32 ` Alexei Starovoitov 2019-11-28 3:32 ` Alexei Starovoitov 2019-11-28 4:18 ` Jason Wang 2019-11-28 4:18 ` Jason Wang 2019-12-01 16:54 ` David Ahern 2019-12-01 16:54 ` David Ahern 2019-12-02 2:48 ` Jason Wang 2019-12-02 2:48 ` Jason Wang
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