Re: [libvirt] [RFC PATCH] Add proxy FS (9p) support to libvirt

On Tue, Jan 17, 2012 at 10:48:15AM +0530, M. Mohan Kumar wrote: > Is it okay to add the sub-element "virtfs-proxy-helper" under "devices" > element? Proxy helper binary is common for all 9p proxy FS devices, so it > can not be placed under "filesystems" element. Hmm, what is the version compatibility like between QEMU and the proxy helper. eg, will we be able to use a version 1.1 QEMU, with a version 1.2 virtfs-proxy-helper, or vica-verca. I'd probably expect that QEMU will always want a precisely matched virtfs-proxy-helper version. It feels to me like we should just form a proxy helper binary path, based on the path to the corresponding QEMU binary. eg, if the guest is using /home/berrange/qemu-git/bin/qemu-system-x86_64, then we should automatically use /home/berrange/qemu-git/libexec/virtfs-proxy-helper

Or, alternatively, perhaps QEMU itself should be made to tell us where the helper lives. eg something like # qemu -build-config virtfs-proxy-helper-path=/home/berrange/qemu-git/libexec/virtfs-proxy-help er then libvirt would always be ensured to have the right binary to match QEMU. There is a similar need for the QEMU net device helper program In general I think one of these approachs is better than added anything else to the XML. This raises interesting questions wrt sVirt / SELinux integration. ie do we need to run each helper program under a dedicated SELinux context to separate them. I think we probably will need to, but I'll have to thing about this some more