| Message ID | cover.1627463617.git.lorenzo@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | mvneta: introduce XDP multi-buffer support | expand |
> From: Lorenzo Bianconi <lorenzo@kernel.org> > > This series introduce XDP multi-buffer support. The mvneta driver is > the first to support these new "non-linear" xdp_{buff,frame}. Reviewers > please focus on how these new types of xdp_{buff,frame} packets > traverse the different layers and the layout design. It is on purpose > that BPF-helpers are kept simple, as we don't want to expose the > internal layout to allow later changes. I sent the cover-letter. Sorry for the noise. Regards, Lorenzo > > The main idea for the new multi-buffer layout is to reuse the same > layout used for non-linear SKB. This rely on the "skb_shared_info" > struct at the end of the first buffer to link together subsequent > buffers. Keeping the layout compatible with SKBs is also done to ease > and speedup creating a SKB from an xdp_{buff,frame}. > Converting xdp_frame to SKB and deliver it to the network stack is shown > in patch 05/18 (e.g. cpumaps). > > A multi-buffer bit (mb) has been introduced in the flags field of xdp_{buff,frame} > structure to notify the bpf/network layer if this is a xdp multi-buffer frame > (mb = 1) or not (mb = 0). > The mb bit will be set by a xdp multi-buffer capable driver only for > non-linear frames maintaining the capability to receive linear frames > without any extra cost since the skb_shared_info structure at the end > of the first buffer will be initialized only if mb is set. > Moreover the flags field in xdp_{buff,frame} will be reused even for > xdp rx csum offloading in future series. > > Typical use cases for this series are: > - Jumbo-frames > - Packet header split (please see Google’s use-case @ NetDevConf 0x14, [0]) > - TSO > > The two following ebpf helpers (and related selftests) has been introduced: > - bpf_xdp_adjust_data: > Move xdp_md->data and xdp_md->data_end pointers in subsequent fragments > according to the offset provided by the ebpf program. This helper can be > used to read/write values in frame payload. > - bpf_xdp_get_buff_len: > Return the total frame size (linear + paged parts) > > bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into > account xdp multi-buff frames. > > More info about the main idea behind this approach can be found here [1][2]. > > Changes since v9: > - introduce bpf_xdp_adjust_data helper and related selftest > - add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info > - introduce xdp_update_skb_shared_info utility routine in ordere to not reset > frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb > - simplify bpf_xdp_copy routine > > Changes since v8: > - add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff > - switch back to skb_shared_info implementation from previous xdp_shared_info > one > - avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance > regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance > penalties for regular codebase > - add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx > - add data_len field in skb_shared_info struct > - introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag > > Changes since v7: > - rebase on top of bpf-next > - fix sparse warnings > - improve comments for frame_length in include/net/xdp.h > > Changes since v6: > - the main difference respect to previous versions is the new approach proposed > by Eelco to pass full length of the packet to eBPF layer in XDP context > - reintroduce multi-buff support to eBPF kself-tests > - reintroduce multi-buff support to bpf_xdp_adjust_tail helper > - introduce multi-buffer support to bpf_xdp_copy helper > - rebase on top of bpf-next > > Changes since v5: > - rebase on top of bpf-next > - initialize mb bit in xdp_init_buff() and drop per-driver initialization > - drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame() > - postpone introduction of frame_length field in XDP ctx to another series > - minor changes > > Changes since v4: > - rebase ontop of bpf-next > - introduce xdp_shared_info to build xdp multi-buff instead of using the > skb_shared_info struct > - introduce frame_length in xdp ctx > - drop previous bpf helpers > - fix bpf_xdp_adjust_tail for xdp multi-buff > - introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail > - fix xdp_return_frame_bulk for xdp multi-buff > > Changes since v3: > - rebase ontop of bpf-next > - add patch 10/13 to copy back paged data from a xdp multi-buff frame to > userspace buffer for xdp multi-buff selftests > > Changes since v2: > - add throughput measurements > - drop bpf_xdp_adjust_mb_header bpf helper > - introduce selftest for xdp multibuffer > - addressed comments on bpf_xdp_get_frags_count > - introduce xdp multi-buff support to cpumaps > > Changes since v1: > - Fix use-after-free in xdp_return_{buff/frame} > - Introduce bpf helpers > - Introduce xdp_mb sample program > - access skb_shared_info->nr_frags only on the last fragment > > Changes since RFC: > - squash multi-buffer bit initialization in a single patch > - add mvneta non-linear XDP buff support for tx side > > [0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy > [1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org > [2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section) > > Eelco Chaudron (3): > bpf: add multi-buff support to the bpf_xdp_adjust_tail() API > bpf: add multi-buffer support to xdp copy helpers > bpf: update xdp_adjust_tail selftest to include multi-buffer > > Lorenzo Bianconi (15): > net: skbuff: add size metadata to skb_shared_info for xdp > xdp: introduce flags field in xdp_buff/xdp_frame > net: mvneta: update mb bit before passing the xdp buffer to eBPF layer > net: mvneta: simplify mvneta_swbm_add_rx_fragment management > net: xdp: add xdp_update_skb_shared_info utility routine > net: marvell: rely on xdp_update_skb_shared_info utility routine > xdp: add multi-buff support to xdp_return_{buff/frame} > net: mvneta: add multi buffer support to XDP_TX > net: mvneta: enable jumbo frames for XDP > bpf: introduce bpf_xdp_get_buff_len helper > bpf: move user_size out of bpf_test_init > bpf: introduce multibuff support to bpf_prog_test_run_xdp() > bpf: test_run: add xdp_shared_info pointer in bpf_test_finish > signature > net: xdp: introduce bpf_xdp_adjust_data helper > bpf: add bpf_xdp_adjust_data selftest > > drivers/net/ethernet/marvell/mvneta.c | 213 ++++++++++-------- > include/linux/skbuff.h | 6 +- > include/net/xdp.h | 95 +++++++- > include/uapi/linux/bpf.h | 38 ++++ > kernel/trace/bpf_trace.c | 3 + > net/bpf/test_run.c | 117 ++++++++-- > net/core/filter.c | 210 ++++++++++++++++- > net/core/xdp.c | 76 ++++++- > tools/include/uapi/linux/bpf.h | 38 ++++ > .../bpf/prog_tests/xdp_adjust_data.c | 55 +++++ > .../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++++ > .../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++---- > .../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +- > .../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 ++- > .../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +- > .../bpf/progs/test_xdp_update_frags.c | 49 ++++ > 16 files changed, 1044 insertions(+), 169 deletions(-) > create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_data.c > create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_frags.c > > -- > 2.31.1 >
On Wed, Jul 28, 2021 at 2:47 AM Lorenzo Bianconi <lorenzo.bianconi@redhat.com> wrote: > > > From: Lorenzo Bianconi <lorenzo@kernel.org> > > > > This series introduce XDP multi-buffer support. The mvneta driver is > > the first to support these new "non-linear" xdp_{buff,frame}. Reviewers > > please focus on how these new types of xdp_{buff,frame} packets > > traverse the different layers and the layout design. It is on purpose > > that BPF-helpers are kept simple, as we don't want to expose the > > internal layout to allow later changes. > > I sent the cover-letter. Sorry for the noise. > > Regards, > Lorenzo > > > > > The main idea for the new multi-buffer layout is to reuse the same > > layout used for non-linear SKB. This rely on the "skb_shared_info" > > struct at the end of the first buffer to link together subsequent > > buffers. Keeping the layout compatible with SKBs is also done to ease > > and speedup creating a SKB from an xdp_{buff,frame}. > > Converting xdp_frame to SKB and deliver it to the network stack is shown > > in patch 05/18 (e.g. cpumaps). > > > > A multi-buffer bit (mb) has been introduced in the flags field of xdp_{buff,frame} > > structure to notify the bpf/network layer if this is a xdp multi-buffer frame > > (mb = 1) or not (mb = 0). > > The mb bit will be set by a xdp multi-buffer capable driver only for > > non-linear frames maintaining the capability to receive linear frames > > without any extra cost since the skb_shared_info structure at the end > > of the first buffer will be initialized only if mb is set. > > Moreover the flags field in xdp_{buff,frame} will be reused even for > > xdp rx csum offloading in future series. > > > > Typical use cases for this series are: > > - Jumbo-frames > > - Packet header split (please see Google’s use-case @ NetDevConf 0x14, [0]) > > - TSO > > > > The two following ebpf helpers (and related selftests) has been introduced: > > - bpf_xdp_adjust_data: > > Move xdp_md->data and xdp_md->data_end pointers in subsequent fragments > > according to the offset provided by the ebpf program. This helper can be > > used to read/write values in frame payload. > > - bpf_xdp_get_buff_len: > > Return the total frame size (linear + paged parts) > > > > bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into > > account xdp multi-buff frames. > > Seems like your changes are breaking selftests in no-alu32 mode ([0]). Please take a look. [0] https://github.com/kernel-patches/bpf/runs/3197530080?check_suite_focus=true > > More info about the main idea behind this approach can be found here [1][2]. > > > > Changes since v9: > > - introduce bpf_xdp_adjust_data helper and related selftest > > - add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info > > - introduce xdp_update_skb_shared_info utility routine in ordere to not reset > > frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb > > - simplify bpf_xdp_copy routine > > > > Changes since v8: > > - add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff > > - switch back to skb_shared_info implementation from previous xdp_shared_info > > one > > - avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance > > regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance > > penalties for regular codebase > > - add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx > > - add data_len field in skb_shared_info struct > > - introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag > > > > Changes since v7: > > - rebase on top of bpf-next > > - fix sparse warnings > > - improve comments for frame_length in include/net/xdp.h > > > > Changes since v6: > > - the main difference respect to previous versions is the new approach proposed > > by Eelco to pass full length of the packet to eBPF layer in XDP context > > - reintroduce multi-buff support to eBPF kself-tests > > - reintroduce multi-buff support to bpf_xdp_adjust_tail helper > > - introduce multi-buffer support to bpf_xdp_copy helper > > - rebase on top of bpf-next > > > > Changes since v5: > > - rebase on top of bpf-next > > - initialize mb bit in xdp_init_buff() and drop per-driver initialization > > - drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame() > > - postpone introduction of frame_length field in XDP ctx to another series > > - minor changes > > > > Changes since v4: > > - rebase ontop of bpf-next > > - introduce xdp_shared_info to build xdp multi-buff instead of using the > > skb_shared_info struct > > - introduce frame_length in xdp ctx > > - drop previous bpf helpers > > - fix bpf_xdp_adjust_tail for xdp multi-buff > > - introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail > > - fix xdp_return_frame_bulk for xdp multi-buff > > > > Changes since v3: > > - rebase ontop of bpf-next > > - add patch 10/13 to copy back paged data from a xdp multi-buff frame to > > userspace buffer for xdp multi-buff selftests > > > > Changes since v2: > > - add throughput measurements > > - drop bpf_xdp_adjust_mb_header bpf helper > > - introduce selftest for xdp multibuffer > > - addressed comments on bpf_xdp_get_frags_count > > - introduce xdp multi-buff support to cpumaps > > > > Changes since v1: > > - Fix use-after-free in xdp_return_{buff/frame} > > - Introduce bpf helpers > > - Introduce xdp_mb sample program > > - access skb_shared_info->nr_frags only on the last fragment > > > > Changes since RFC: > > - squash multi-buffer bit initialization in a single patch > > - add mvneta non-linear XDP buff support for tx side > > > > [0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy > > [1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org > > [2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section) > > > > Eelco Chaudron (3): > > bpf: add multi-buff support to the bpf_xdp_adjust_tail() API > > bpf: add multi-buffer support to xdp copy helpers > > bpf: update xdp_adjust_tail selftest to include multi-buffer > > > > Lorenzo Bianconi (15): > > net: skbuff: add size metadata to skb_shared_info for xdp > > xdp: introduce flags field in xdp_buff/xdp_frame > > net: mvneta: update mb bit before passing the xdp buffer to eBPF layer > > net: mvneta: simplify mvneta_swbm_add_rx_fragment management > > net: xdp: add xdp_update_skb_shared_info utility routine > > net: marvell: rely on xdp_update_skb_shared_info utility routine > > xdp: add multi-buff support to xdp_return_{buff/frame} > > net: mvneta: add multi buffer support to XDP_TX > > net: mvneta: enable jumbo frames for XDP > > bpf: introduce bpf_xdp_get_buff_len helper > > bpf: move user_size out of bpf_test_init > > bpf: introduce multibuff support to bpf_prog_test_run_xdp() > > bpf: test_run: add xdp_shared_info pointer in bpf_test_finish > > signature > > net: xdp: introduce bpf_xdp_adjust_data helper > > bpf: add bpf_xdp_adjust_data selftest > > > > drivers/net/ethernet/marvell/mvneta.c | 213 ++++++++++-------- > > include/linux/skbuff.h | 6 +- > > include/net/xdp.h | 95 +++++++- > > include/uapi/linux/bpf.h | 38 ++++ > > kernel/trace/bpf_trace.c | 3 + > > net/bpf/test_run.c | 117 ++++++++-- > > net/core/filter.c | 210 ++++++++++++++++- > > net/core/xdp.c | 76 ++++++- > > tools/include/uapi/linux/bpf.h | 38 ++++ > > .../bpf/prog_tests/xdp_adjust_data.c | 55 +++++ > > .../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++++ > > .../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++---- > > .../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +- > > .../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 ++- > > .../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +- > > .../bpf/progs/test_xdp_update_frags.c | 49 ++++ > > 16 files changed, 1044 insertions(+), 169 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_data.c > > create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_frags.c > > > > -- > > 2.31.1 > >
[...] > > > bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into > > > account xdp multi-buff frames. > > > > > Seems like your changes are breaking selftests in no-alu32 mode ([0]). > Please take a look. > > [0] https://github.com/kernel-patches/bpf/runs/3197530080?check_suite_focus=true Hi Andrii, for no-alu32 mode, it seems the verifiers is complaining when the program is trying to access the packet payload using the updated value for offset: if (data[offset] != 0xaa) /* marker * ... as double check, if I use the proper constant value for offset (1480 = 5000 (original offset) - 3520 (buff0 length)) the test if fine. I need to understand the root cause of the issue. Regards, Lorenzo > > > > More info about the main idea behind this approach can be found here [1][2]. > > > > > > Changes since v9: > > > - introduce bpf_xdp_adjust_data helper and related selftest > > > - add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info > > > - introduce xdp_update_skb_shared_info utility routine in ordere to not reset > > > frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb > > > - simplify bpf_xdp_copy routine > > > > > > Changes since v8: > > > - add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff > > > - switch back to skb_shared_info implementation from previous xdp_shared_info > > > one > > > - avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance > > > regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance > > > penalties for regular codebase > > > - add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx > > > - add data_len field in skb_shared_info struct > > > - introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag > > > > > > Changes since v7: > > > - rebase on top of bpf-next > > > - fix sparse warnings > > > - improve comments for frame_length in include/net/xdp.h > > > > > > Changes since v6: > > > - the main difference respect to previous versions is the new approach proposed > > > by Eelco to pass full length of the packet to eBPF layer in XDP context > > > - reintroduce multi-buff support to eBPF kself-tests > > > - reintroduce multi-buff support to bpf_xdp_adjust_tail helper > > > - introduce multi-buffer support to bpf_xdp_copy helper > > > - rebase on top of bpf-next > > > > > > Changes since v5: > > > - rebase on top of bpf-next > > > - initialize mb bit in xdp_init_buff() and drop per-driver initialization > > > - drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame() > > > - postpone introduction of frame_length field in XDP ctx to another series > > > - minor changes > > > > > > Changes since v4: > > > - rebase ontop of bpf-next > > > - introduce xdp_shared_info to build xdp multi-buff instead of using the > > > skb_shared_info struct > > > - introduce frame_length in xdp ctx > > > - drop previous bpf helpers > > > - fix bpf_xdp_adjust_tail for xdp multi-buff > > > - introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail > > > - fix xdp_return_frame_bulk for xdp multi-buff > > > > > > Changes since v3: > > > - rebase ontop of bpf-next > > > - add patch 10/13 to copy back paged data from a xdp multi-buff frame to > > > userspace buffer for xdp multi-buff selftests > > > > > > Changes since v2: > > > - add throughput measurements > > > - drop bpf_xdp_adjust_mb_header bpf helper > > > - introduce selftest for xdp multibuffer > > > - addressed comments on bpf_xdp_get_frags_count > > > - introduce xdp multi-buff support to cpumaps > > > > > > Changes since v1: > > > - Fix use-after-free in xdp_return_{buff/frame} > > > - Introduce bpf helpers > > > - Introduce xdp_mb sample program > > > - access skb_shared_info->nr_frags only on the last fragment > > > > > > Changes since RFC: > > > - squash multi-buffer bit initialization in a single patch > > > - add mvneta non-linear XDP buff support for tx side > > > > > > [0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy > > > [1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org > > > [2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section) > > > > > > Eelco Chaudron (3): > > > bpf: add multi-buff support to the bpf_xdp_adjust_tail() API > > > bpf: add multi-buffer support to xdp copy helpers > > > bpf: update xdp_adjust_tail selftest to include multi-buffer > > > > > > Lorenzo Bianconi (15): > > > net: skbuff: add size metadata to skb_shared_info for xdp > > > xdp: introduce flags field in xdp_buff/xdp_frame > > > net: mvneta: update mb bit before passing the xdp buffer to eBPF layer > > > net: mvneta: simplify mvneta_swbm_add_rx_fragment management > > > net: xdp: add xdp_update_skb_shared_info utility routine > > > net: marvell: rely on xdp_update_skb_shared_info utility routine > > > xdp: add multi-buff support to xdp_return_{buff/frame} > > > net: mvneta: add multi buffer support to XDP_TX > > > net: mvneta: enable jumbo frames for XDP > > > bpf: introduce bpf_xdp_get_buff_len helper > > > bpf: move user_size out of bpf_test_init > > > bpf: introduce multibuff support to bpf_prog_test_run_xdp() > > > bpf: test_run: add xdp_shared_info pointer in bpf_test_finish > > > signature > > > net: xdp: introduce bpf_xdp_adjust_data helper > > > bpf: add bpf_xdp_adjust_data selftest > > > > > > drivers/net/ethernet/marvell/mvneta.c | 213 ++++++++++-------- > > > include/linux/skbuff.h | 6 +- > > > include/net/xdp.h | 95 +++++++- > > > include/uapi/linux/bpf.h | 38 ++++ > > > kernel/trace/bpf_trace.c | 3 + > > > net/bpf/test_run.c | 117 ++++++++-- > > > net/core/filter.c | 210 ++++++++++++++++- > > > net/core/xdp.c | 76 ++++++- > > > tools/include/uapi/linux/bpf.h | 38 ++++ > > > .../bpf/prog_tests/xdp_adjust_data.c | 55 +++++ > > > .../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++++ > > > .../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++---- > > > .../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +- > > > .../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 ++- > > > .../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +- > > > .../bpf/progs/test_xdp_update_frags.c | 49 ++++ > > > 16 files changed, 1044 insertions(+), 169 deletions(-) > > > create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_data.c > > > create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_frags.c > > > > > > -- > > > 2.31.1 > > >
From: Lorenzo Bianconi <lorenzo@kernel.org> This series introduce XDP multi-buffer support. The mvneta driver is the first to support these new "non-linear" xdp_{buff,frame}. Reviewers please focus on how these new types of xdp_{buff,frame} packets traverse the different layers and the layout design. It is on purpose that BPF-helpers are kept simple, as we don't want to expose the internal layout to allow later changes. The main idea for the new multi-buffer layout is to reuse the same layout used for non-linear SKB. This rely on the "skb_shared_info" struct at the end of the first buffer to link together subsequent buffers. Keeping the layout compatible with SKBs is also done to ease and speedup creating a SKB from an xdp_{buff,frame}. Converting xdp_frame to SKB and deliver it to the network stack is shown in patch 05/18 (e.g. cpumaps). A multi-buffer bit (mb) has been introduced in the flags field of xdp_{buff,frame} structure to notify the bpf/network layer if this is a xdp multi-buffer frame (mb = 1) or not (mb = 0). The mb bit will be set by a xdp multi-buffer capable driver only for non-linear frames maintaining the capability to receive linear frames without any extra cost since the skb_shared_info structure at the end of the first buffer will be initialized only if mb is set. Moreover the flags field in xdp_{buff,frame} will be reused even for xdp rx csum offloading in future series. Typical use cases for this series are: - Jumbo-frames - Packet header split (please see Google’s use-case @ NetDevConf 0x14, [0]) - TSO The two following ebpf helpers (and related selftests) has been introduced: - bpf_xdp_adjust_data: Move xdp_md->data and xdp_md->data_end pointers in subsequent fragments according to the offset provided by the ebpf program. This helper can be used to read/write values in frame payload. - bpf_xdp_get_buff_len: Return the total frame size (linear + paged parts) bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into account xdp multi-buff frames. More info about the main idea behind this approach can be found here [1][2]. Changes since v9: - introduce bpf_xdp_adjust_data helper and related selftest - add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info - introduce xdp_update_skb_shared_info utility routine in ordere to not reset frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb - simplify bpf_xdp_copy routine Changes since v8: - add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff - switch back to skb_shared_info implementation from previous xdp_shared_info one - avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance penalties for regular codebase - add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx - add data_len field in skb_shared_info struct - introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag Changes since v7: - rebase on top of bpf-next - fix sparse warnings - improve comments for frame_length in include/net/xdp.h Changes since v6: - the main difference respect to previous versions is the new approach proposed by Eelco to pass full length of the packet to eBPF layer in XDP context - reintroduce multi-buff support to eBPF kself-tests - reintroduce multi-buff support to bpf_xdp_adjust_tail helper - introduce multi-buffer support to bpf_xdp_copy helper - rebase on top of bpf-next Changes since v5: - rebase on top of bpf-next - initialize mb bit in xdp_init_buff() and drop per-driver initialization - drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame() - postpone introduction of frame_length field in XDP ctx to another series - minor changes Changes since v4: - rebase ontop of bpf-next - introduce xdp_shared_info to build xdp multi-buff instead of using the skb_shared_info struct - introduce frame_length in xdp ctx - drop previous bpf helpers - fix bpf_xdp_adjust_tail for xdp multi-buff - introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail - fix xdp_return_frame_bulk for xdp multi-buff Changes since v3: - rebase ontop of bpf-next - add patch 10/13 to copy back paged data from a xdp multi-buff frame to userspace buffer for xdp multi-buff selftests Changes since v2: - add throughput measurements - drop bpf_xdp_adjust_mb_header bpf helper - introduce selftest for xdp multibuffer - addressed comments on bpf_xdp_get_frags_count - introduce xdp multi-buff support to cpumaps Changes since v1: - Fix use-after-free in xdp_return_{buff/frame} - Introduce bpf helpers - Introduce xdp_mb sample program - access skb_shared_info->nr_frags only on the last fragment Changes since RFC: - squash multi-buffer bit initialization in a single patch - add mvneta non-linear XDP buff support for tx side [0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy [1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org [2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section) Eelco Chaudron (3): bpf: add multi-buff support to the bpf_xdp_adjust_tail() API bpf: add multi-buffer support to xdp copy helpers bpf: update xdp_adjust_tail selftest to include multi-buffer Lorenzo Bianconi (15): net: skbuff: add size metadata to skb_shared_info for xdp xdp: introduce flags field in xdp_buff/xdp_frame net: mvneta: update mb bit before passing the xdp buffer to eBPF layer net: mvneta: simplify mvneta_swbm_add_rx_fragment management net: xdp: add xdp_update_skb_shared_info utility routine net: marvell: rely on xdp_update_skb_shared_info utility routine xdp: add multi-buff support to xdp_return_{buff/frame} net: mvneta: add multi buffer support to XDP_TX net: mvneta: enable jumbo frames for XDP bpf: introduce bpf_xdp_get_buff_len helper bpf: move user_size out of bpf_test_init bpf: introduce multibuff support to bpf_prog_test_run_xdp() bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature net: xdp: introduce bpf_xdp_adjust_data helper bpf: add bpf_xdp_adjust_data selftest drivers/net/ethernet/marvell/mvneta.c | 213 ++++++++++-------- include/linux/skbuff.h | 6 +- include/net/xdp.h | 95 +++++++- include/uapi/linux/bpf.h | 38 ++++ kernel/trace/bpf_trace.c | 3 + net/bpf/test_run.c | 117 ++++++++-- net/core/filter.c | 210 ++++++++++++++++- net/core/xdp.c | 76 ++++++- tools/include/uapi/linux/bpf.h | 38 ++++ .../bpf/prog_tests/xdp_adjust_data.c | 55 +++++ .../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++++ .../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++---- .../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +- .../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 ++- .../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +- .../bpf/progs/test_xdp_update_frags.c | 49 ++++ 16 files changed, 1044 insertions(+), 169 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_data.c create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_frags.c