The existing error trace event is renamed to have a name prefix
matching its source file & to remove the redundant first arg that
adds no useful information.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The eBPF code is currently reporting error messages through trace
events. Trace events are fine for debugging, but they are not to be
considered the primary error reporting mechanism, as their output
is inaccessible to callers.
This adds an "Error **errp" parameter to all methods which have
important error scenarios to report to the caller.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
A design pattern of
trace_foo_error("descriptive string")
is undesirable because it does not allow for filtering trace events
based on the error scenario. Split eBPF error trace event into three
separate events to address this filtering need.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Various static methods have checks on their parameters which were
already checked immediately before the method was invoked. Drop
these redundat checks to simplify the following commit which adds
formal error reporting.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Recent commit "qapi: Smarter camel_to_upper() to reduce need for
'prefix'" added a temporary 'prefix' to delay changing the generated
code.
Revert it. This improves EbpfProgramID's generated enumeration
constant prefix from EBPF_PROGRAMID to EBPF_PROGRAM_ID.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240904111836.3273842-7-armbru@redhat.com>
There was an issue with Qemu build with "--disable-system".
The traces could be generated and the build fails.
The traces were 'cut out' for previous patches, and overall,
the 'system' source set should be used like in pre-'eBPF blob' patches.
Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
The kernel documentation says:
> The value stored can be of any size, however, all array elements are
> aligned to 8 bytes.
https://www.kernel.org/doc/html/v6.8/bpf/map_array.html
Fixes: 333b3e5fab ("ebpf: Added eBPF map update through mmap.")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
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-andrew@daynix.com/
Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
It allows using file descriptors of eBPF provided
outside of QEMU.
QEMU may be run without capabilities for eBPF and run
RSS program provided by management tool(g.e. libvirt).
Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Changed eBPF map updates through mmaped array.
Mmaped arrays provide direct access to map data.
It should omit using bpf_map_update_elem() call,
which may require capabilities that are not present.
Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
bpf_program__set_<TYPE> functions have been deprecated since libbpf 0.8.
Replace with the equivalent bpf_program__set_type call to avoid a
deprecation warning.
Signed-off-by: Haochen Tong <i@hexchain.org>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Added function that loads RSS eBPF program.
Added stub functions for RSS eBPF loader.
Added meson and configuration options.
By default, eBPF feature enabled if libbpf is present in the build system.
libbpf checked in configuration shell script and meson script.
Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Daniel P. Berrangé