[PATCH 0/5] eBPF RSS Helper support.

[Andrew Melnychenko]

This series of patches provides the ability to initialize eBPF RSS steering
with the helper.
Now, virtio-net devices can accept eBPF programs and maps through properties
as external file descriptors. Access to the eBPF map is direct through mmap()
call, so it should not require additional capabilities to bpf* calls.
eBPF file descriptors can be passed to QEMU from parent process or by unix
socket with sendfd() qmp command.
The helper is provided that would load eBPF RSS program/maps and pass fd to
the called process(in future - Libvirtd) through unix socket.
Because of structures stored in the maps, it's crucial that the helper provides 
a proper eBPF program. That's why the stamp was added to the helper and
QEMU may check the binary. Also, additional qmp command was added for checking
the stamp.
Overall, the basic scenario of using the helper looks like this:
 * Libvirt checks for ebpf_fds property.
 * Libvirt ask QEMU for the proper helper(where is located and proper stamp)
 * Libvirt calls the helper with BPF capabilities and retrieves fds.
 * Libvirt launches the QEMU with eBPF fds passed.

Changes since RFC:
 * refactored/rebased code.
 * changed qmp command.
 * refactored helper.
 
Andrew Melnychenko (5):
  ebpf: Added eBPF initialization by fds and map update.
  virtio-net: Added property to load eBPF RSS with fds.
  qmp: Added the helper stamp check.
  ebpf_rss_helper: Added helper for eBPF RSS.
  qmp: Added find-ebpf-rss-helper command.

 ebpf/ebpf_rss-stub.c                       |   6 +
 ebpf/ebpf_rss.c                            | 120 ++++++--
 ebpf/ebpf_rss.h                            |  10 +
 ebpf/qemu-ebpf-rss-helper.c                | 132 +++++++++
 hw/net/virtio-net.c                        |  77 ++++-
 include/hw/virtio/virtio-net.h             |   1 +
 meson.build                                |  47 ++-
 monitor/meson.build                        |   1 +
 monitor/qemu-ebpf-rss-helper-stamp-utils.c | 322 +++++++++++++++++++++
 monitor/qemu-ebpf-rss-helper-stamp-utils.h |  39 +++
 monitor/qmp-cmds.c                         |  28 ++
 qapi/misc.json                             |  42 +++
 12 files changed, 785 insertions(+), 40 deletions(-)
 create mode 100644 ebpf/qemu-ebpf-rss-helper.c
 create mode 100644 monitor/qemu-ebpf-rss-helper-stamp-utils.c
 create mode 100644 monitor/qemu-ebpf-rss-helper-stamp-utils.h

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2.39.1