Enabling Qemu/KVM Filesystem Passthrough Centos 7

Question

I have a system running Centos 7 with the stock qemu/KVM code. I have several virtual servers running on this system and would like to enable the filesystem passthrough option. So far, I have not had any luck. I have downloaded ther kernel sources from Kernel.org and compiled with all the 9p / 9p2000 modules installed, but the option "Filesystem" option is still greyed out in Virt-Manager with the message "not supported for this hypervisor/libvirt combination". I have tried Centos 6, 7 and Ubuntu 14.04 as guest OS, and none of these seems to help.

Is there any way to fix this issue? I would gladly recompile qemu/libvirtd to fix the issue if it can be done safely without breaking anything. (I have had bad luck compiling things under Centos in the past. The paths don't seem to be what the source expects and things get put in the wrong places.)

Solution

I was able to get this working by following these instructions:

http://scientificlinuxforum.org/index.php?showtopic=2858

I had to re-create my virtual machines by importing each existing drive image to get them all working again, but other than that it all went well.

Have not had much chance to check performance yet.

Comments

[Michael Hampton]

I didn't bother; I just use an NFSv4/TCP server to share files with Linux guests, and Samba to share with Windows guests. The official word from Red Hat is that 9p is a steaming pile of crap.