[RFC PATCH 00/10] VirtioNet RSS support

[Andrew Melnichenko]

Hi,
Yes, the work is in progress. Now. I'm working with a proper solution for
the eBPF RSS helper.

On Wed, Oct 20, 2021 at 3:23 PM Nikolay Shirokovskiy <
nshirokovskiy at virtuozzo.com> wrote:

> Hi, Andrew.
>
> We in Virtuozzo are interested in this functionality too. Do you plan to
> continue your work on it?
>
> Nikolay
>
> пн, 16 авг. 2021 г. в 15:00, Andrew Melnichenko <andrew at daynix.com>:
>
>> Ping
>>
>> On Wed, Jul 28, 2021 at 11:17 AM Andrew Melnychenko <andrew at daynix.com>
>> wrote:
>>
>>> This series of patches add RSS property support for virtio-net-pci.
>>>
>>> Virtio RSS effectively works with TAP devices, it requires additional
>>> vectors for VirtioNet, queues for TAP device, and vCPU cores.
>>> Example of device configuration:
>>> ```
>>> <interface type="network">
>>>   <mac address="52:54:00:c4:90:25"/>
>>>   <source network="default"/>
>>>   <model type="virtio"/>
>>>   <driver name="qemu" queues="9" rss="on" rss_hash_report="off"/>
>>>   <address type="pci" domain="0x0000" bus="0x01" slot="0x00"
>>> function="0x0"/>
>>> </interface>
>>> ```
>>>
>>> Capability "rss" enables RSS, "rss_hash_report" - enables hashes in
>>> vheader.
>>> Qemu uses eBPF program as RSS driver.
>>> For loading RSS eBPF program, the helper is used.
>>> Path to the helper is provided by Qemu through "query-helper-paths" qmp
>>> command.
>>> The helper "qemu-ebpf-rss-helper" is built with Qemu and may differ from
>>> build to build.
>>> So it's required that the Qemu should provide a proper helper path.
>>> Libvirt would call the helper and receive the program and map fd through
>>> unix socket.
>>> Fds would be passed to Qemu in "ebpf_rss_fds" property by passing to
>>> child process or unix socket.
>>> If libvirt would fail at helper call or Qemu didn't provide the path,
>>> the Qemu would be launched without "ebpf_rss_fds" property.
>>> Without "ebpf_rss_fds" property, Qemu would try to load eBPF program by
>>> itself - usually, it would require additional system permissions.
>>> Qemu may use "in-qemu" RSS as a fallback option, which will not require
>>> system
>>> permissions, but doesn't work with vhost TAP.
>>>
>>> Qemu patches:
>>> https://lists.nongnu.org/archive/html/qemu-devel/2021-07/msg03535.html
>>>
>>> Andrew Melnychenko (10):
>>>   domain_conf: Added configs for RSS and Hash report.
>>>   qemu_capabilities: Added capabilites for qemu's "rss" and "hash".
>>>   qemu_command: Added "rss" and "hash" properties.
>>>   virsocket: Added receive for multiple fds.
>>>   qemu_capabilities: Added capability for qemu's "ebpf_rss_fds".
>>>   qemu_capabilities: Added capability for ebpf helper path.
>>>   qemu_interface: Added ebpf helper call.
>>>   qemu_command: Added ebpf RSS helper call for NIC creation.
>>>   qemu_hotplug: Added helper call for hotplug NIC.
>>>   docs: Added descriptions for "rss" and "rss_hash_report"
>>>     configurations.
>>>
>>>  docs/formatdomain.rst        | 16 +++++++
>>>  src/conf/domain_conf.c       | 31 +++++++++++++-
>>>  src/conf/domain_conf.h       |  2 +
>>>  src/libvirt_private.syms     |  1 +
>>>  src/qemu/qemu_capabilities.c | 48 +++++++++++++++++++++
>>>  src/qemu/qemu_capabilities.h |  5 +++
>>>  src/qemu/qemu_command.c      | 46 +++++++++++++++++++-
>>>  src/qemu/qemu_command.h      |  2 +
>>>  src/qemu/qemu_hotplug.c      | 30 ++++++++++++-
>>>  src/qemu/qemu_interface.c    | 54 +++++++++++++++++++++++
>>>  src/qemu/qemu_interface.h    |  2 +
>>>  src/qemu/qemu_monitor.c      |  9 ++++
>>>  src/qemu/qemu_monitor.h      |  3 ++
>>>  src/qemu/qemu_monitor_json.c | 50 ++++++++++++++++++++++
>>>  src/qemu/qemu_monitor_json.h |  3 ++
>>>  src/qemu/qemu_validate.c     | 16 +++++++
>>>  src/util/virsocket.c         | 83 ++++++++++++++++++++++++++++++++++++
>>>  src/util/virsocket.h         |  2 +
>>>  18 files changed, 399 insertions(+), 4 deletions(-)
>>>
>>> --
>>> 2.31.1
>>>
>>>
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