On 6/17/25 1:59 PM, Ilya Maximets wrote:
On 6/4/25 1:29 PM, Daniel Borkmann wrote:
Extend 'inhibit=on' setting with the option to specify a pinned XSK map
path along with a starting index (default 0) to push the created XSK
sockets into. Example usage:
# ./build/qemu-system-x86_64 [...] \
-netdev
af-xdp,ifname=enp2s0f0np0,id=net0,mode=native,queues=2,start-queue=14,inhibit=on,map-path=/sys/fs/bpf/xsks_map,map-start-index=14
\
-device virtio-net-pci,netdev=net0 [...]
This is useful for the case where an existing XDP program with XSK map
is present on the AF_XDP supported phys device and the XSK map is not
yet populated. For example, the former could have been pre-loaded onto
the netdevice by a control plane, which later launches qemu to populate
it with XSK sockets.
Normally, the main idea behind 'inhibit=on' is that the qemu instance
doesn't need to have a lot of privileges to use the pre-loaded program
and the pre-created sockets, but this mentioned use-case here is different
where qemu still needs privileges to create the sockets.
The 'map-start-index' parameter is optional and defaults to 0. It allows
flexible placement of the XSK sockets, and is up to the user to specify
when the XDP program with XSK map was already preloaded. In the simplest
case the queue-to-map-slot mapping is just 1:1 based on ctx->rx_queue_index
but the user might as well have a different scheme (or smaller map size,
e.g. ctx->rx_queue_index % max_size) to push the inbound traffic to one
of the XSK sockets.
Note that the bpf_xdp_query_id() is now only tested for 'inhibit=off'
since only in the latter case the libxdp takes care of installing the
XDP program which was installed based on the s->xdp_flags pointing to
either driver or skb mode. For 'inhibit=on' we don't make any assumptions
and neither go down the path of probing all possible options in which
way the user installed the XDP program.
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Cc: Ilya Maximets <i.maxim...@ovn.org>
Cc: Jason Wang <jasow...@redhat.com>
Cc: Anton Protopopov <as...@isovalent.com>
---
net/af-xdp.c | 80 +++++++++++++++++++++++++++++++++++++++++++++----
qapi/net.json | 29 +++++++++++-------
qemu-options.hx | 23 ++++++++++++--
3 files changed, 114 insertions(+), 18 deletions(-)
Hi, Daniel. Thanks for v3!
checkpatch complains about 2 issues in the patch - a missing braces and
onle too long line that can be wrapped.
Thanks for review, I wasn't aware of this, will fix these two in v4!
There also seems to be some issue on a cleanup path that you attempt to
fix in the second patch, so I reply about it there.
Best regards, Ilya Maximets.
