Re: [libvirt] [Qemu-devel] Re: Libvirt debug API

Richard W.M. Jones wrote: That forces the shell script to be relatively complicated and recognise all qemu arguments (including version specific ones) to skip the ones with parameters - and to know where to look for the real target executable is. It's not a very friendly way to add or change parts of specific subsystems, for example modifying a blockdev parameter, but it can be done that way if necessary. It's not that hard to write this for trivial extra options: <emulator>/bin/sh -c 'qemu "$0" "$@" -extra-flag'</emulator> (if that works). But for things like modifications to particular devices, wouldn't it be better to associate "add cache=special option" to a section about one of the blockdevs which libvirt knows about, rather than the awful prospect of parsing libvirt's output to guess which of three -device arguments corresponds with the second SCSI drive mentioned in the libvirt config - which might not necessarily be the second on the command line, even. Parsing libvirt output and having to guess which option corresponds to what from the libvirt config sounds very fragile and also a rather large amount of effort for something which should be easy. And then there's modifying how network tap devices are set up and other networking, outside qemu, but requested by libvirt. Doing that in <emulator> sounds like a bad idea, but script hooks are the only sane way to make networking fit every environment and requirement. Ideally without forcing the hook writer to reimplement the normal network setup from scratch just to tweak it a bit. I apologise if libvirt already provides such hooks - I haven't looked at that part of it. -- Jamie