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
