[RFC PATCH 00/10] VirtioNet RSS support

[Nikolay Shirokovskiy]

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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