[4/5] ebpf_rss_helper: Added helper for eBPF RSS.

Helper program. Loads eBPF RSS program and maps and passes them through unix socket.
Libvirt may launch this helper and pass eBPF fds to qemu virtio-net.
Also, libbpf dependency for now is exclusively for Linux.
Libbpf is used for eBPF RSS steering, which is supported only by Linux TAP.
There is no reason yet to build eBPF loader and helper for non-Linux systems,
even if libbpf is present.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
---
 ebpf/qemu-ebpf-rss-helper.c | 132 ++++++++++++++++++++++++++++++++++++
 meson.build                 |  37 ++++++----
 2 files changed, 156 insertions(+), 13 deletions(-)
 create mode 100644 ebpf/qemu-ebpf-rss-helper.c

On Sun, Feb 19, 2023 at 06:20:59PM +0200, Andrew Melnychenko wrote:
> Helper program. Loads eBPF RSS program and maps and passes them through unix socket.
> Libvirt may launch this helper and pass eBPF fds to qemu virtio-net.
> Also, libbpf dependency for now is exclusively for Linux.
> Libbpf is used for eBPF RSS steering, which is supported only by Linux TAP.
> There is no reason yet to build eBPF loader and helper for non-Linux systems,
> even if libbpf is present.
> 
> Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
> ---
>  ebpf/qemu-ebpf-rss-helper.c | 132 ++++++++++++++++++++++++++++++++++++
>  meson.build                 |  37 ++++++----
>  2 files changed, 156 insertions(+), 13 deletions(-)
>  create mode 100644 ebpf/qemu-ebpf-rss-helper.c
> 
> diff --git a/ebpf/qemu-ebpf-rss-helper.c b/ebpf/qemu-ebpf-rss-helper.c
> new file mode 100644
> index 0000000000..348d26bcdd
> --- /dev/null
> +++ b/ebpf/qemu-ebpf-rss-helper.c
> @@ -0,0 +1,132 @@
> +/*
> + * eBPF RSS Helper
> + *
> + * Developed by Daynix Computing LTD (http://www.daynix.com)
> + *
> + * Authors:
> + *  Andrew Melnychenko <andrew@daynix.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.

Is there a reason for specifying GPL version 2 only ?

Unless this has copied code from one of the existing GPLv2-only files
in QEMU, the requirement (listed in LICENSE) is that new contributions
will be GPLv2-or-later, except for a handful of sub-directories.



> + *
> + * Description: This is helper program for libvirtd.
> + *              It loads eBPF RSS program and passes fds through unix socket.
> + *              Built by meson, target - 'qemu-ebpf-rss-helper'.
> + */
> +
> +#include <stdio.h>
> +#include <stdint.h>
> +#include <stdlib.h>
> +#include <stdbool.h>
> +#include <getopt.h>
> +#include <memory.h>
> +#include <errno.h>
> +#include <sys/socket.h>
> +
> +#include "ebpf_rss.h"
> +
> +#include "qemu-ebpf-rss-helper-stamp.h"
> +
> +void QEMU_EBPF_RSS_HELPER_STAMP(void) {}
> +
> +static int send_fds(int socket, int *fds, int n)
> +{
> +    struct msghdr msg = {};
> +    struct cmsghdr *cmsg = NULL;
> +    char buf[CMSG_SPACE(n * sizeof(int))];
> +    char dummy_buffer = 0;
> +    struct iovec io = { .iov_base = &dummy_buffer,
> +                        .iov_len = sizeof(dummy_buffer) };
> +
> +    memset(buf, 0, sizeof(buf));
> +
> +    msg.msg_iov = &io;
> +    msg.msg_iovlen = 1;
> +    msg.msg_control = buf;
> +    msg.msg_controllen = sizeof(buf);
> +
> +    cmsg = CMSG_FIRSTHDR(&msg);
> +    cmsg->cmsg_level = SOL_SOCKET;
> +    cmsg->cmsg_type = SCM_RIGHTS;
> +    cmsg->cmsg_len = CMSG_LEN(n * sizeof(int));
> +
> +    memcpy(CMSG_DATA(cmsg), fds, n * sizeof(int));
> +
> +    return sendmsg(socket, &msg, 0);
> +}
> +
> +static void print_help_and_exit(const char *prog, int exitcode)
> +{
> +    fprintf(stderr, "%s - load eBPF RSS program for qemu and pass eBPF fds"
> +            " through unix socket.\n", prog);
> +    fprintf(stderr, "\t--fd <num>, -f <num> - unix socket file descriptor"
> +            " used to pass eBPF fds.\n");
> +    fprintf(stderr, "\t--help, -h - this help.\n");
> +    exit(exitcode);
> +}
> +
> +int main(int argc, char **argv)
> +{
> +    char *fd_string = NULL;
> +    int unix_fd = 0;
> +    struct EBPFRSSContext ctx = {};
> +    int fds[EBPF_RSS_MAX_FDS] = {};
> +    int ret = -1;
> +
> +    for (;;) {
> +        int c;
> +        static struct option long_options[] = {
> +                {"help",  no_argument, 0, 'h'},
> +                {"fd",  required_argument, 0, 'f'},
> +                {0, 0, 0, 0}
> +        };
> +        c = getopt_long(argc, argv, "hf:",
> +                long_options, NULL);
> +
> +        if (c == -1) {
> +            break;
> +        }
> +
> +        switch (c) {
> +        case 'f':
> +            fd_string = optarg;
> +            break;
> +        case 'h':
> +        default:
> +            print_help_and_exit(argv[0],
> +                    c == 'h' ? EXIT_SUCCESS : EXIT_FAILURE);
> +        }
> +    }
> +
> +    if (!fd_string) {
> +        fprintf(stderr, "Unix file descriptor not present.\n");
> +        print_help_and_exit(argv[0], EXIT_FAILURE);
> +    }
> +
> +    unix_fd = atoi(fd_string);
> +
> +    if (!unix_fd) {
> +        fprintf(stderr, "Unix file descriptor is invalid.\n");
> +        return EXIT_FAILURE;
> +    }
> +
> +    ebpf_rss_init(&ctx);
> +    if (!ebpf_rss_load(&ctx)) {
> +        fprintf(stderr, "Can't load ebpf.\n");
> +        return EXIT_FAILURE;
> +    }
> +    fds[0] = ctx.program_fd;
> +    fds[1] = ctx.map_configuration;
> +    fds[2] = ctx.map_toeplitz_key;
> +    fds[3] = ctx.map_indirections_table;
> +
> +    ret = send_fds(unix_fd, fds, EBPF_RSS_MAX_FDS);
> +    if (ret < 0) {
> +        fprintf(stderr, "Issue while sending fds: %s.\n", strerror(errno));
> +    }
> +
> +    ebpf_rss_unload(&ctx);
> +
> +    return ret < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
> +}
> +
> diff --git a/meson.build b/meson.build
> index b409912aed..6e6e2f3e40 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -1632,19 +1632,22 @@ elif get_option('vduse_blk_export').disabled()
>  endif
>  
>  # libbpf
> -libbpf = dependency('libbpf', required: get_option('bpf'), method: 'pkg-config')
> -if libbpf.found() and not cc.links('''
> -   #include <bpf/libbpf.h>
> -   int main(void)
> -   {
> -     bpf_object__destroy_skeleton(NULL);
> -     return 0;
> -   }''', dependencies: libbpf)
> -  libbpf = not_found
> -  if get_option('bpf').enabled()
> -    error('libbpf skeleton test failed')
> -  else
> -    warning('libbpf skeleton test failed, disabling')
> +libbpf = not_found
> +if targetos == 'linux'
> +  libbpf = dependency('libbpf', required: get_option('bpf'), method: 'pkg-config')
> +  if libbpf.found() and not cc.links('''
> +    #include <bpf/libbpf.h>
> +    int main(void)
> +    {
> +      bpf_object__destroy_skeleton(NULL);
> +      return 0;
> +    }''', dependencies: libbpf)
> +    libbpf = not_found
> +    if get_option('bpf').enabled()
> +      error('libbpf skeleton test failed')
> +    else
> +      warning('libbpf skeleton test failed, disabling')
> +    endif
>    endif
>  endif
>  
> @@ -3646,6 +3649,14 @@ if have_tools
>                 dependencies: [authz, crypto, io, qom, qemuutil,
>                                libcap_ng, mpathpersist],
>                 install: true)
> +
> +    if libbpf.found()
> +        executable('qemu-ebpf-rss-helper', files(
> +                   'ebpf/qemu-ebpf-rss-helper.c', 'ebpf/ebpf_rss.c'),
> +                   dependencies: [qemuutil, libbpf, glib],
> +                   install: true,
> +                   install_dir: get_option('libexecdir'))
> +    endif
>    endif
>  
>    if have_ivshmem
> -- 
> 2.39.1
> 

With regards,
Daniel

Hi,

On Mon, Feb 20, 2023 at 11:54 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> On Sun, Feb 19, 2023 at 06:20:59PM +0200, Andrew Melnychenko wrote:
> > Helper program. Loads eBPF RSS program and maps and passes them through unix socket.
> > Libvirt may launch this helper and pass eBPF fds to qemu virtio-net.
> > Also, libbpf dependency for now is exclusively for Linux.
> > Libbpf is used for eBPF RSS steering, which is supported only by Linux TAP.
> > There is no reason yet to build eBPF loader and helper for non-Linux systems,
> > even if libbpf is present.
> >
> > Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
> > ---
> >  ebpf/qemu-ebpf-rss-helper.c | 132 ++++++++++++++++++++++++++++++++++++
> >  meson.build                 |  37 ++++++----
> >  2 files changed, 156 insertions(+), 13 deletions(-)
> >  create mode 100644 ebpf/qemu-ebpf-rss-helper.c
> >
> > diff --git a/ebpf/qemu-ebpf-rss-helper.c b/ebpf/qemu-ebpf-rss-helper.c
> > new file mode 100644
> > index 0000000000..348d26bcdd
> > --- /dev/null
> > +++ b/ebpf/qemu-ebpf-rss-helper.c
> > @@ -0,0 +1,132 @@
> > +/*
> > + * eBPF RSS Helper
> > + *
> > + * Developed by Daynix Computing LTD (http://www.daynix.com)
> > + *
> > + * Authors:
> > + *  Andrew Melnychenko <andrew@daynix.com>
> > + *
> > + * This work is licensed under the terms of the GNU GPL, version 2.  See
> > + * the COPYING file in the top-level directory.
>
> Is there a reason for specifying GPL version 2 only ?
>
> Unless this has copied code from one of the existing GPLv2-only files
> in QEMU, the requirement (listed in LICENSE) is that new contributions
> will be GPLv2-or-later, except for a handful of sub-directories.
>

Yeah - I'll change it. Thank you.

>
>
> > + *
> > + * Description: This is helper program for libvirtd.
> > + *              It loads eBPF RSS program and passes fds through unix socket.
> > + *              Built by meson, target - 'qemu-ebpf-rss-helper'.
> > + */
> > +
> > +#include <stdio.h>
> > +#include <stdint.h>
> > +#include <stdlib.h>
> > +#include <stdbool.h>
> > +#include <getopt.h>
> > +#include <memory.h>
> > +#include <errno.h>
> > +#include <sys/socket.h>
> > +
> > +#include "ebpf_rss.h"
> > +
> > +#include "qemu-ebpf-rss-helper-stamp.h"
> > +
> > +void QEMU_EBPF_RSS_HELPER_STAMP(void) {}
> > +
> > +static int send_fds(int socket, int *fds, int n)
> > +{
> > +    struct msghdr msg = {};
> > +    struct cmsghdr *cmsg = NULL;
> > +    char buf[CMSG_SPACE(n * sizeof(int))];
> > +    char dummy_buffer = 0;
> > +    struct iovec io = { .iov_base = &dummy_buffer,
> > +                        .iov_len = sizeof(dummy_buffer) };
> > +
> > +    memset(buf, 0, sizeof(buf));
> > +
> > +    msg.msg_iov = &io;
> > +    msg.msg_iovlen = 1;
> > +    msg.msg_control = buf;
> > +    msg.msg_controllen = sizeof(buf);
> > +
> > +    cmsg = CMSG_FIRSTHDR(&msg);
> > +    cmsg->cmsg_level = SOL_SOCKET;
> > +    cmsg->cmsg_type = SCM_RIGHTS;
> > +    cmsg->cmsg_len = CMSG_LEN(n * sizeof(int));
> > +
> > +    memcpy(CMSG_DATA(cmsg), fds, n * sizeof(int));
> > +
> > +    return sendmsg(socket, &msg, 0);
> > +}
> > +
> > +static void print_help_and_exit(const char *prog, int exitcode)
> > +{
> > +    fprintf(stderr, "%s - load eBPF RSS program for qemu and pass eBPF fds"
> > +            " through unix socket.\n", prog);
> > +    fprintf(stderr, "\t--fd <num>, -f <num> - unix socket file descriptor"
> > +            " used to pass eBPF fds.\n");
> > +    fprintf(stderr, "\t--help, -h - this help.\n");
> > +    exit(exitcode);
> > +}
> > +
> > +int main(int argc, char **argv)
> > +{
> > +    char *fd_string = NULL;
> > +    int unix_fd = 0;
> > +    struct EBPFRSSContext ctx = {};
> > +    int fds[EBPF_RSS_MAX_FDS] = {};
> > +    int ret = -1;
> > +
> > +    for (;;) {
> > +        int c;
> > +        static struct option long_options[] = {
> > +                {"help",  no_argument, 0, 'h'},
> > +                {"fd",  required_argument, 0, 'f'},
> > +                {0, 0, 0, 0}
> > +        };
> > +        c = getopt_long(argc, argv, "hf:",
> > +                long_options, NULL);
> > +
> > +        if (c == -1) {
> > +            break;
> > +        }
> > +
> > +        switch (c) {
> > +        case 'f':
> > +            fd_string = optarg;
> > +            break;
> > +        case 'h':
> > +        default:
> > +            print_help_and_exit(argv[0],
> > +                    c == 'h' ? EXIT_SUCCESS : EXIT_FAILURE);
> > +        }
> > +    }
> > +
> > +    if (!fd_string) {
> > +        fprintf(stderr, "Unix file descriptor not present.\n");
> > +        print_help_and_exit(argv[0], EXIT_FAILURE);
> > +    }
> > +
> > +    unix_fd = atoi(fd_string);
> > +
> > +    if (!unix_fd) {
> > +        fprintf(stderr, "Unix file descriptor is invalid.\n");
> > +        return EXIT_FAILURE;
> > +    }
> > +
> > +    ebpf_rss_init(&ctx);
> > +    if (!ebpf_rss_load(&ctx)) {
> > +        fprintf(stderr, "Can't load ebpf.\n");
> > +        return EXIT_FAILURE;
> > +    }
> > +    fds[0] = ctx.program_fd;
> > +    fds[1] = ctx.map_configuration;
> > +    fds[2] = ctx.map_toeplitz_key;
> > +    fds[3] = ctx.map_indirections_table;
> > +
> > +    ret = send_fds(unix_fd, fds, EBPF_RSS_MAX_FDS);
> > +    if (ret < 0) {
> > +        fprintf(stderr, "Issue while sending fds: %s.\n", strerror(errno));
> > +    }
> > +
> > +    ebpf_rss_unload(&ctx);
> > +
> > +    return ret < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
> > +}
> > +
> > diff --git a/meson.build b/meson.build
> > index b409912aed..6e6e2f3e40 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -1632,19 +1632,22 @@ elif get_option('vduse_blk_export').disabled()
> >  endif
> >
> >  # libbpf
> > -libbpf = dependency('libbpf', required: get_option('bpf'), method: 'pkg-config')
> > -if libbpf.found() and not cc.links('''
> > -   #include <bpf/libbpf.h>
> > -   int main(void)
> > -   {
> > -     bpf_object__destroy_skeleton(NULL);
> > -     return 0;
> > -   }''', dependencies: libbpf)
> > -  libbpf = not_found
> > -  if get_option('bpf').enabled()
> > -    error('libbpf skeleton test failed')
> > -  else
> > -    warning('libbpf skeleton test failed, disabling')
> > +libbpf = not_found
> > +if targetos == 'linux'
> > +  libbpf = dependency('libbpf', required: get_option('bpf'), method: 'pkg-config')
> > +  if libbpf.found() and not cc.links('''
> > +    #include <bpf/libbpf.h>
> > +    int main(void)
> > +    {
> > +      bpf_object__destroy_skeleton(NULL);
> > +      return 0;
> > +    }''', dependencies: libbpf)
> > +    libbpf = not_found
> > +    if get_option('bpf').enabled()
> > +      error('libbpf skeleton test failed')
> > +    else
> > +      warning('libbpf skeleton test failed, disabling')
> > +    endif
> >    endif
> >  endif
> >
> > @@ -3646,6 +3649,14 @@ if have_tools
> >                 dependencies: [authz, crypto, io, qom, qemuutil,
> >                                libcap_ng, mpathpersist],
> >                 install: true)
> > +
> > +    if libbpf.found()
> > +        executable('qemu-ebpf-rss-helper', files(
> > +                   'ebpf/qemu-ebpf-rss-helper.c', 'ebpf/ebpf_rss.c'),
> > +                   dependencies: [qemuutil, libbpf, glib],
> > +                   install: true,
> > +                   install_dir: get_option('libexecdir'))
> > +    endif
> >    endif
> >
> >    if have_ivshmem
> > --
> > 2.39.1
> >
>
> With regards,
> Daniel
> --
> |: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
> |: https://libvirt.org         -o-            https://fstop138.berrange.com :|
> |: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|
>