On Mon, Dec 18, 2023 at 2:54 PM Markus Armbruster <arm...@redhat.com> wrote:
> Uh, I missed this one, my apologies! Let me have a quick look... > > Commit message style nitpick: > > qmp: Add command to retrieve eBPF blob > > or > > qmp: New command to retrieve eBPF blob > > It's a title, not a sentence. > > Andrew Melnychenko <and...@daynix.com> writes: > > > Now, the binary objects may be retrieved by id. > > It would require for future qmp commands that may require specific > > eBPF blob. > > > > Added command "request-ebpf". This command returns > > eBPF program encoded base64. The program taken from the > > skeleton and essentially is an ELF object that can be > > loaded in the future with libbpf. > > > > The reason to use the command to provide the eBPF object > > instead of a separate artifact was to avoid issues related > > to finding the eBPF itself. eBPF object is an ELF binary > > that contains the eBPF program and eBPF map description(BTF). > > Overall, eBPF object should contain the program and enough > > metadata to create/load eBPF with libbpf. As the eBPF > > maps/program should correspond to QEMU, the eBPF can't > > be used from different QEMU build. > > > > The first solution was a helper that comes with QEMU > > and loads appropriate eBPF objects. And the issue is > > to find a proper helper if the system has several > > different QEMUs installed and/or built from the source, > > which helpers may not be compatible. > > > > Another issue is QEMU updating while there is a running > > QEMU instance. With an updated helper, it may not be > > possible to hotplug virtio-net device to the already > > running QEMU. Overall, requesting the eBPF object from > > QEMU itself solves possible failures with acceptable effort. > > > > Links: > > [PATCH 3/5] qmp: Added the helper stamp check. > > https://lore.kernel.org/all/20230219162100.174318-4-and...@daynix.com/ > > > > Signed-off-by: Andrew Melnychenko <and...@daynix.com> > > [...] > > > diff --git a/qapi/ebpf.json b/qapi/ebpf.json > > new file mode 100644 > > index 0000000000..ba78407148 > > --- /dev/null > > +++ b/qapi/ebpf.json > > @@ -0,0 +1,66 @@ > > +# -*- Mode: Python -*- > > +# vim: filetype=python > > +# > > +# This work is licensed under the terms of the GNU GPL, version 2 or > later. > > +# See the COPYING file in the top-level directory. > > + > > +## > > +# = eBPF Objects > > +# > > +# eBPF object is an ELF binary that contains the eBPF > > +# program and eBPF map description(BTF). Overall, eBPF > > +# object should contain the program and enough metadata > > +# to create/load eBPF with libbpf. As the eBPF maps/program > > +# should correspond to QEMU, the eBPF can't be used from > > +# different QEMU build. > > An introduction, nice! > > Two spaces between sentences for consistency, please. > > Wrap comment lines at column 70, like this: > > # eBPF object is an ELF binary that contains the eBPF program and eBPF > # map description(BTF). Overall, eBPF object should contain the > # program and enough metadata to create/load eBPF with libbpf. As the > # eBPF maps/program should correspond to QEMU, the eBPF can't be used > # from different QEMU build. > > > +# > > +# Currently, there is a possible eBPF for receive-side scaling (RSS). > > +# > > +## > > + > > +## > > +# @EbpfObject: > > +# > > +# An eBPF ELF object. > > +# > > +# @object: the eBPF object encoded in base64 > > +# > > +# Since: 8.2 > > Won't make 8.2, so bump to 9.0. More of the same below, not noting it > again. > Will there be 8.3? > > > +## > > +{ 'struct': 'EbpfObject', > > + 'data': {'object': 'str'}, > > + 'if': 'CONFIG_EBPF' } > > + > > +## > > +# @EbpfProgramID: > > +# > > +# The eBPF programs that can be gotten with request-ebpf. > > +# > > +# @rss: Receive side scaling, technology that allows steering traffic > > +# between queues by calculation hash. Users may set up > > +# indirection table and hash/packet types configurations. Used > > +# with virtio-net. > > +# > > +# Since: 8.2 > > +## > > +{ 'enum': 'EbpfProgramID', > > + 'if': 'CONFIG_EBPF', > > + 'data': [ { 'name': 'rss' } ] } > > + > > +## > > +# @request-ebpf: > > +# > > +# Retrieve an eBPF object that can be loaded with libbpf. Management > > +# applications (g.e. libvirt) may load it and pass file descriptors to > > +# QEMU, so they can run running QEMU without BPF capabilities. > > +# > > +# @id: The ID of the program to return. > > +# > > +# Returns: eBPF object encoded in base64. > > +# > > +# Since: 8.2 > > +## > > +{ 'command': 'request-ebpf', > > + 'data': { 'id': 'EbpfProgramID' }, > > + 'returns': 'EbpfObject', > > + 'if': 'CONFIG_EBPF' } > > diff --git a/qapi/meson.build b/qapi/meson.build > > index 60a668b343..90047dae1c 100644 > > --- a/qapi/meson.build > > +++ b/qapi/meson.build > > @@ -33,6 +33,7 @@ qapi_all_modules = [ > > 'crypto', > > 'cxl', > > 'dump', > > + 'ebpf', > > 'error', > > 'introspect', > > 'job', > > diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json > > index 6594afba31..2c82a49bae 100644 > > --- a/qapi/qapi-schema.json > > +++ b/qapi/qapi-schema.json > > @@ -53,6 +53,7 @@ > > { 'include': 'char.json' } > > { 'include': 'dump.json' } > > { 'include': 'net.json' } > > +{ 'include': 'ebpf.json' } > > { 'include': 'rdma.json' } > > { 'include': 'rocker.json' } > > { 'include': 'tpm.json' } > > With the (minor) doc comment fixes: > Acked-by: Markus Armbruster <arm...@redhat.com> > >
