>From what I've seen in QEMU and libvirt's code, I would say that discovering whether the spice server supports LZ4 is not a matter of adding a new QMP command. That would not scale very well with new command line options. I would suggest something more general. For instance, having the command query- command-line-options return also the allowed values for string parameters. That would output "lz4" for parameter "image-compression" in option "spice", among the other compression methods. Another possibility would be a new QMP command that returns the capabilities of the spice server, as defined in the spice protocol. They include the SPICE_DISPLAY_CAP_LZ4_COMPRESSION capability, if the spice server supports LZ4. In any case, I think it is out of the scope of this patch. El Martes, 27 de enero de 2015 09:26:11 Markus Armbruster escribió: > Eric Blake <eblake@xxxxxxxxxx> writes: > > On 01/26/2015 01:48 AM, Javier Celaya wrote: > >> Sorry, I forgot to patch the command-line help. Hope it helps. > >> > >>>> Recently, SPICE included the lz4 compression algorithm. This patch adds > >>>> a command line option to select it. > >>> > >>> How is libvirt going to introspect whether the command line supports > >>> this option? Is there some QMP command that lists the set of valid > >>> compression formats understood by a given qemu binary? > > > > No, patching the command line --help does NOT help libvirt. It needs to > > be discoverable via QMP to be introspectible, as scraping --help output > > is not machine-friendly. (That said, you DO want to expose it in --help > > output; I'm just complaining that --help output alone is not enough). > > We should really, really, really provide access to (the relevant subset > of) the QAPI schema over QMP! Until we get that, useful progress is > delayed by problems like this one, and we keep growing special-purpose > solutions to problems like this one. _______________________________________________ Spice-devel mailing list Spice-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/spice-devel