On 22 Dec 2022, at 1:06, Ilya Maximets wrote:
> AF_XDP functions was deprecated in libbpf 0.7 and moved to libxdp.
> Functions bpf_get/set_link_xdp_id() was deprecated in libbpf 0.8
> and replaced with bpf_xdp_query_id() and bpf_xdp_attach/detach().
>
> Updating configuration and source code to accommodate above changes
> and allow building OVS with AF_XDP support on newer systems:
>
> - Checking the version of libbpf by detecting availability
> of bpf_xdp_detach.
>
> - Checking availability of the libxdp in a system by looking
> for a library providing libxdp_strerror(), if libbpf is
> newer than 0.6. And checking for xsk.h header provided by
> libxdp-dev[el].
>
> - Use xsk.h from libbpf if it is older than 0.7 and not linking
> with lbxdp in this case as there are known incompatible
> versions of libxdp in distributions.
>
> - Check for the NEED_WAKEUP feature replaced with direct checking
> in the source code if XDP_USE_NEED_WAKEUP is defined.
>
> - Checking availability of bpf_xdp_query_id and bpf_xdp_detach
> and using them instead of deprecated APIs. Fall back to old
> functions if not found.
>
> - Dropped LIBBPF_LDADD variable as it makes library and function
> detection much harder without providing any actual benefits.
> AC_SEARCH_LIBS is used instead and it allows use of AC_CHECK_FUNCS.
>
> - Header includes moved around to files where they are actually used.
>
> - Removed libelf dependency as it is not really used.
>
> With these changes it should be possible to build OVS with either:
>
> - libbpf built from the kernel sources (5.19 or older).
> - libbpf < 0.7 provided in distributions.
> - libxdp and libbpf >= 0.7 provided in newer distributions.
>
> While it is technically possible to build with libbpf 0.7+ without
> libxdp at the moment we're not allowing that for a few reasons.
> First, required functions in libbpf are deprecated and can be removed
> in future releases. Second, support for all these combinations makes
> the detection code fairly complex.
> AFAIK, most of the distributions packaging libbpf 0.7+ do package
> libxdp as well.
>
> libxdp added as a build dependency for Fedora build since all
> supported versions of Fedora are packaging this library.
>
> Signed-off-by: Ilya Maximets <[email protected]>
Changes look good to me, one small nit below you can probably fix at commit
time.
Acked-by: Eelco Chaudron <[email protected]>
> ---
> NEWS | 2 ++
> acinclude.m4 | 28 ++++++++++++++----------
> lib/automake.mk | 1 -
> lib/libopenvswitch.pc.in | 2 +-
> lib/netdev-afxdp-pool.c | 2 ++
> lib/netdev-afxdp-pool.h | 5 -----
> lib/netdev-afxdp.c | 38 ++++++++++++++++++++++++++-------
> rhel/openvswitch-fedora.spec.in | 2 +-
> 8 files changed, 53 insertions(+), 27 deletions(-)
>
> diff --git a/NEWS b/NEWS
> index 92d33c291..ce5d11d73 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -2,6 +2,8 @@ Post-v3.0.0
> --------------------
> - ovs-vswitchd now detects changes in CPU affinity and adjusts the number
> of handler and revalidator threads if necessary.
> + - AF_XDP:
> + * Added support for building with libxdp and libbpf >= 0.7.
> - ovs-appctl:
> * "ovs-appctl ofproto/trace" command can now display port names with the
> "--names" option.
> diff --git a/acinclude.m4 b/acinclude.m4
> index aa9af5506..e47e925b3 100644
> --- a/acinclude.m4
> +++ b/acinclude.m4
> @@ -251,7 +251,7 @@ AC_DEFUN([OVS_FIND_DEPENDENCY], [
>
> dnl OVS_CHECK_LINUX_AF_XDP
> dnl
> -dnl Check both Linux kernel AF_XDP and libbpf support
> +dnl Check both Linux kernel AF_XDP and libbpf/libxdp support
> AC_DEFUN([OVS_CHECK_LINUX_AF_XDP], [
> AC_ARG_ENABLE([afxdp],
> [AS_HELP_STRING([--enable-afxdp], [Enable AF-XDP support])],
> @@ -270,8 +270,21 @@ AC_DEFUN([OVS_CHECK_LINUX_AF_XDP], [
> AC_CHECK_HEADER([linux/if_xdp.h], [],
> [AC_MSG_ERROR([unable to find linux/if_xdp.h for AF_XDP support])])
>
> - AC_CHECK_HEADER([bpf/xsk.h], [],
> - [AC_MSG_ERROR([unable to find bpf/xsk.h for AF_XDP support])])
> + OVS_FIND_DEPENDENCY([libbpf_strerror], [bpf], [libbpf])
> + AC_CHECK_FUNCS([bpf_xdp_query_id bpf_xdp_detach])
> +
> + if test "x$ac_cv_func_bpf_xdp_detach" = xyes; then
> + dnl We have libbpf >= 0.7. Look for libxdp as xsk functions
> + dnl were moved into this library.
> + OVS_FIND_DEPENDENCY([libxdp_strerror], [xdp], [libxdp])
> + AC_CHECK_HEADER([xdp/xsk.h],
> + AC_DEFINE([HAVE_LIBXDP], [1], [xsk.h is supplied with libxdp]),
> + AC_MSG_ERROR([unable to find xdp/xsk.h for AF_XDP support]))
> + else
> + dnl libbpf < 0.7 contains all the necessary functionality.
> + AC_CHECK_HEADER([bpf/xsk.h], [],
> + [AC_MSG_ERROR([unable to find bpf/xsk.h for AF_XDP support])])
> + fi
>
> AC_CHECK_FUNCS([pthread_spin_lock], [],
> [AC_MSG_ERROR([unable to find pthread_spin_lock for AF_XDP support])])
> @@ -280,13 +293,6 @@ AC_DEFUN([OVS_CHECK_LINUX_AF_XDP], [
>
> AC_DEFINE([HAVE_AF_XDP], [1],
> [Define to 1 if AF_XDP support is available and enabled.])
> - LIBBPF_LDADD=" -lbpf -lelf"
> - AC_SUBST([LIBBPF_LDADD])
> -
> - AC_CHECK_DECL([xsk_ring_prod__needs_wakeup], [
> - AC_DEFINE([HAVE_XDP_NEED_WAKEUP], [1],
> - [XDP need wakeup support detected in xsk.h.])
> - ], [], [[#include <bpf/xsk.h>]])
> fi
> AM_CONDITIONAL([HAVE_AF_XDP], test "$AF_XDP_ENABLE" = true)
> ])
> @@ -357,7 +363,7 @@ AC_DEFUN([OVS_CHECK_DPDK], [
> ], [], [[#include <rte_config.h>]])
>
> AC_CHECK_DECL([RTE_NET_AF_XDP], [
> - LIBBPF_LDADD="-lbpf"
> + OVS_FIND_DEPENDENCY([libbpf_strerror], [bpf], [libbpf])
> ], [], [[#include <rte_config.h>]])
>
> AC_CHECK_DECL([RTE_LIBRTE_VHOST_NUMA], [
> diff --git a/lib/automake.mk b/lib/automake.mk
> index a0fabe38f..61bdc308f 100644
> --- a/lib/automake.mk
> +++ b/lib/automake.mk
> @@ -9,7 +9,6 @@ lib_LTLIBRARIES += lib/libopenvswitch.la
>
> lib_libopenvswitch_la_LIBADD = $(SSL_LIBS)
> lib_libopenvswitch_la_LIBADD += $(CAPNG_LDADD)
> -lib_libopenvswitch_la_LIBADD += $(LIBBPF_LDADD)
>
>
> if WIN32
> diff --git a/lib/libopenvswitch.pc.in b/lib/libopenvswitch.pc.in
> index 44fbb1f9f..a5f4d3947 100644
> --- a/lib/libopenvswitch.pc.in
> +++ b/lib/libopenvswitch.pc.in
> @@ -7,5 +7,5 @@ Name: libopenvswitch
> Description: Open vSwitch library
> Version: @VERSION@
> Libs: -L${libdir} -lopenvswitch
> -Libs.private: @LIBS@ @SSL_LIBS@ @CAPNG_LDADD@ @LIBBPF_LDADD@
> +Libs.private: @LIBS@ @SSL_LIBS@ @CAPNG_LDADD@
> Cflags: -I${includedir}
> diff --git a/lib/netdev-afxdp-pool.c b/lib/netdev-afxdp-pool.c
> index 3386d2dcf..f56a7b29e 100644
> --- a/lib/netdev-afxdp-pool.c
> +++ b/lib/netdev-afxdp-pool.c
> @@ -15,6 +15,8 @@
> */
> #include <config.h>
>
Remove the extra newline here?
> +#include <errno.h>
> +
> #include "dp-packet.h"
> #include "netdev-afxdp-pool.h"
> #include "openvswitch/util.h"
> diff --git a/lib/netdev-afxdp-pool.h b/lib/netdev-afxdp-pool.h
> index f929b9489..6681cf539 100644
> --- a/lib/netdev-afxdp-pool.h
> +++ b/lib/netdev-afxdp-pool.h
> @@ -19,12 +19,7 @@
>
> #ifdef HAVE_AF_XDP
>
> -#include <bpf/xsk.h>
> -#include <errno.h>
> -#include <stdbool.h>
> -
> #include "openvswitch/thread.h"
> -#include "ovs-atomic.h"
>
> /* LIFO ptr_array. */
> struct umem_pool {
> diff --git a/lib/netdev-afxdp.c b/lib/netdev-afxdp.c
> index 4d57efa5c..f8995da1f 100644
> --- a/lib/netdev-afxdp.c
> +++ b/lib/netdev-afxdp.c
> @@ -21,6 +21,11 @@
> #include "netdev-afxdp.h"
> #include "netdev-afxdp-pool.h"
>
> +#ifdef HAVE_LIBXDP
> +#include <xdp/xsk.h>
> +#else
> +#include <bpf/xsk.h>
> +#endif
> #include <errno.h>
> #include <inttypes.h>
> #include <linux/rtnetlink.h>
> @@ -29,6 +34,7 @@
> #include <numa.h>
> #include <numaif.h>
> #include <poll.h>
> +#include <stdbool.h>
> #include <stdlib.h>
> #include <sys/resource.h>
> #include <sys/socket.h>
> @@ -44,6 +50,7 @@
> #include "openvswitch/list.h"
> #include "openvswitch/thread.h"
> #include "openvswitch/vlog.h"
> +#include "ovs-atomic.h"
> #include "ovs-numa.h"
> #include "packets.h"
> #include "socket-util.h"
> @@ -72,7 +79,7 @@ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5,
> 20);
> #define PROD_NUM_DESCS XSK_RING_PROD__DEFAULT_NUM_DESCS
> #define CONS_NUM_DESCS XSK_RING_CONS__DEFAULT_NUM_DESCS
>
> -#ifdef HAVE_XDP_NEED_WAKEUP
> +#ifdef XDP_USE_NEED_WAKEUP
> #define NEED_WAKEUP_DEFAULT true
> #else
> #define NEED_WAKEUP_DEFAULT false
> @@ -169,7 +176,7 @@ struct netdev_afxdp_tx_lock {
> );
> };
>
> -#ifdef HAVE_XDP_NEED_WAKEUP
> +#ifdef XDP_USE_NEED_WAKEUP
> static inline void
> xsk_rx_wakeup_if_needed(struct xsk_umem_info *umem,
> struct netdev *netdev, int fd)
> @@ -201,7 +208,7 @@ xsk_tx_need_wakeup(struct xsk_socket_info *xsk_info)
> return xsk_ring_prod__needs_wakeup(&xsk_info->tx);
> }
>
> -#else /* !HAVE_XDP_NEED_WAKEUP */
> +#else /* !XDP_USE_NEED_WAKEUP */
> static inline void
> xsk_rx_wakeup_if_needed(struct xsk_umem_info *umem OVS_UNUSED,
> struct netdev *netdev OVS_UNUSED,
> @@ -215,7 +222,7 @@ xsk_tx_need_wakeup(struct xsk_socket_info *xsk_info
> OVS_UNUSED)
> {
> return true;
> }
> -#endif /* HAVE_XDP_NEED_WAKEUP */
> +#endif /* XDP_USE_NEED_WAKEUP */
>
> static void
> netdev_afxdp_cleanup_unused_pool(struct unused_pool *pool)
> @@ -351,7 +358,7 @@ xsk_configure_socket(struct xsk_umem_info *umem, uint32_t
> ifindex,
> cfg.bind_flags = xdp_modes[mode].bind_flags;
> cfg.xdp_flags = xdp_modes[mode].xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST;
>
> -#ifdef HAVE_XDP_NEED_WAKEUP
> +#ifdef XDP_USE_NEED_WAKEUP
> if (use_need_wakeup) {
> cfg.bind_flags |= XDP_USE_NEED_WAKEUP;
> }
> @@ -377,7 +384,11 @@ xsk_configure_socket(struct xsk_umem_info *umem,
> uint32_t ifindex,
> }
>
> /* Make sure the built-in AF_XDP program is loaded. */
> +#ifdef HAVE_BPF_XDP_QUERY_ID
> + ret = bpf_xdp_query_id(ifindex, cfg.xdp_flags, &prog_id);
> +#else
> ret = bpf_get_link_xdp_id(ifindex, &prog_id, cfg.xdp_flags);
> +#endif
> if (ret || !prog_id) {
> if (ret) {
> VLOG_ERR("Get XDP prog ID failed (%s)", ovs_strerror(errno));
> @@ -630,9 +641,9 @@ netdev_afxdp_set_config(struct netdev *netdev, const
> struct smap *args,
> }
>
> need_wakeup = smap_get_bool(args, "use-need-wakeup",
> NEED_WAKEUP_DEFAULT);
> -#ifndef HAVE_XDP_NEED_WAKEUP
> +#ifndef XDP_USE_NEED_WAKEUP
> if (need_wakeup) {
> - VLOG_WARN("XDP need_wakeup is not supported in libbpf.");
> + VLOG_WARN("XDP need_wakeup is not supported in libbpf/libxdp.");
> need_wakeup = false;
> }
> #endif
> @@ -742,7 +753,11 @@ xsk_remove_xdp_program(uint32_t ifindex, enum afxdp_mode
> mode)
> uint32_t ret, prog_id = 0;
>
> /* Check whether XDP program is loaded. */
> +#ifdef HAVE_BPF_XDP_QUERY_ID
> + ret = bpf_xdp_query_id(ifindex, flags, &prog_id);
> +#else
> ret = bpf_get_link_xdp_id(ifindex, &prog_id, flags);
> +#endif
> if (ret) {
> VLOG_ERR("Failed to get XDP prog id (%s)", ovs_strerror(errno));
> return;
> @@ -753,7 +768,14 @@ xsk_remove_xdp_program(uint32_t ifindex, enum afxdp_mode
> mode)
> return;
> }
>
> - bpf_set_link_xdp_fd(ifindex, -1, flags);
> +#ifdef HAVE_BPF_XDP_DETACH
> + if (bpf_xdp_detach(ifindex, flags, NULL) != 0) {
> +#else
> + if (bpf_set_link_xdp_fd(ifindex, -1, flags) != 0) {
> +#endif
> + VLOG_ERR("Failed to detach XDP program (%s) at ifindex %d",
> + ovs_strerror(errno), ifindex);
> + }
> }
>
> void
> diff --git a/rhel/openvswitch-fedora.spec.in b/rhel/openvswitch-fedora.spec.in
> index 8fc6e8ab2..eb5077a21 100644
> --- a/rhel/openvswitch-fedora.spec.in
> +++ b/rhel/openvswitch-fedora.spec.in
> @@ -75,7 +75,7 @@ BuildRequires: dpdk-devel >= 22.11
> Provides: %{name}-dpdk = %{version}-%{release}
> %endif
> %if %{with afxdp}
> -BuildRequires: libbpf-devel numactl-devel
> +BuildRequires: libxdp-devel libbpf-devel numactl-devel
> %endif
> BuildRequires: unbound unbound-devel
>
> --
> 2.38.1
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