[Qemu-devel] [PATCH v2 0/5] fw-cfg: documentation, cleanup, and cmdline blobs

[Gabriel L. Somlo]

Document and clean up fw_cfg; additionally, allow user-provided blobs to
be inserted into fw_cfg via the qemu command line.

Changes since v1:

    - reworked documentation (1/5) as per Laszlo's feedback
      (actual changes detailed below the commit blurb in the actual patch)

    - guest-side write in 2/5 is now a no-op (as opposed to completely
      removing the write_op itself); also removed trace event.

    - reworded commit blurbs for 3/5 and 4/5; the latter now also removes
      a no longer needed trace event.

    - streamlined 5/5 (inserting fw_cfg blobs via command line)
      Specific changes and potentially remaining issues described at length
      below the commit blurb in the actual patch

    - dropped 6th patch (guest-side qga hack to retrieve fw_cfg files by
      name), as it is merely an RFC at this time, and we can continue
      talking about it in its original thread on the mailing list.

I sent out a couple of emails about patch #5 earlier this afternoon,
but please ignore that as I'm bringing up the same issues below the
commit blurb, only hopefully in a way that's a bit more eloquent, or
at least more coherent :)

Thanks for all the feedback, and please let me know what you all think.

  Gabriel

>Summary of patches in v1 of the series:
>
>  1/6: resubmit Jordan's documentation patch from back in 2011
>
>  2/6: remove support for guest-side writes to fw_cfg data port
>       (this also updates the documentation applied earlier in 1/6)
>
>  3/6: add assertion to prevent us from inadvertently introducing memory leaks
>       when adding data blobs to fw_cfg
>
>  4/6: adding fw_cfg blobs with the same file name multiple times is a
>       memory-leaking erroneous thing to do: make qemu properly quit with
>       an error instead of just generating a trace event.
>
>  5/6: allow users to explicitly insert an arbitrary file as a fw_cfg blob
>       via the qemu command line
>
>  6/6: guest-side retrieval of named blob from the fw_cfg device
>       (please do NOT apply 6/6, as I'm just soliciting feedback at this time)


Gabriel L. Somlo (5):
  fw_cfg: add documentation file (docs/specs/fw_cfg.txt)
  fw_cfg: remove support for guest-side data writes
  fw_cfg: prevent selector key conflict
  fw_cfg: prohibit insertion of duplicate fw_cfg file names
  fw_cfg: insert fw_cfg file blobs via qemu cmdline

 docs/specs/fw_cfg.txt     | 192 ++++++++++++++++++++++++++++++++++++++++++++++
 hw/nvram/fw_cfg.c         |  85 +++++++++++---------
 include/hw/nvram/fw_cfg.h |   6 +-
 qemu-options.hx           |  11 +++
 trace-events              |   2 -
 vl.c                      |  27 +++++++
 6 files changed, 282 insertions(+), 41 deletions(-)
 create mode 100644 docs/specs/fw_cfg.txt

-- 
2.1.0