Please enable VirtFS support by rebuilding against libattr1 and libcap2

[Tuomas Jormola]

The current build of qemu-kvm-spice in precise does not support the virtual fs or folder sharing from host to guest. VirtualFS support requires that qemu-kvm-spice is built with libattr1-dev and libcap-dev installed, no other changes needed as it's enabled if these dependencies are found. I rebuilt qemu-linaro source with the attached debdiff attached and now the VirtualFS is enabled. It would be great to have this in precise.

See for more info
http://wiki.qemu.org/Documentation/9psetup - Upstream document about the feature
http://libvirt.org/formatdomain.html#elementsFilesystems - How to enable the VirtualFS feature using libvirt based VMs
https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/782973 - Bug against the qemu-kvm package requesting to support VirtualFS. Since this bug report, also libcap-dev is required.
---
ApportVersion: 1.95-0ubuntu1
Architecture: amd64
DistroRelease: Ubuntu 12.04
NonfreeKernelModules: nvidia
Package: qemu-kvm-spice 1.0.50-2012.03-0ubuntu1
PackageArchitecture: amd64
ProcEnviron:
 TERM=xterm
 SHELL=/bin/bash
 LANG=en_US.UTF-8
 LC_CTYPE=fi_FI.UTF-8
ProcVersionSignature: Ubuntu 3.2.0-20.32-generic 3.2.12
Tags: precise
Uname: Linux 3.2.0-20-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

[Tuomas Jormola (tjormola)]

apport information

[Serge Hallyn (serge-hallyn)]

@Steve Langasek,

just to make sure, will this change the qemu-linaro build? Are you ok with that?

[Steve Langasek (vorlon)]

I haven't checked what impact it has :-) It should have no impact on qemu-user, but I guess it will impact the qemu-system build just as it does the spice build.

I think we should be explicit in any case about turning this support on/off in the configure flags according to what we want to see happen. I have no relevant opinion on whether it should be on for qemu-system, except to say that it's worth investigating.

[Serge Hallyn (serge-hallyn)]

Thanks, Steve.

Since clearly it's too late to enable this feature in this cycle, do you prefer that we explictly turn the support off in the builds for precise immediately? Or simply wait until P+1 to enable it?

(Note btw that there are several bugs open against qemu-kvm stemming from the 9p support)

[Tuomas Jormola (tjormola)]

Well, this particular feature is enabled and working as-is with the binary provided by qemu-kvm. Currently, we have situation where you can have a libvirt based VM that works with <filesystem .../> definition and <devices><emulator>/usr/bin/kvm</emulator>...</devices> but fails if this is changed to /usr/bin/kvm-spice, which enables other goodies related to SPICE. For this reason I wouldn't be too concerned about the possible 9p related issues.. qemu-kvm-spice is already more "unstable" than qemu-kvm but currently it doesn't support all the features the "stable parent" does...

[Steve Langasek (vorlon)]

On Wed, Mar 28, 2012 at 09:44:02PM -0000, Serge Hallyn wrote:
> Since clearly it's too late to enable this feature in this cycle, do you
> prefer that we explictly turn the support off in the builds for precise
> immediately? Or simply wait until P+1 to enable it?

I wouldn't worry for precise, and just enable it for Q.

[Serge Hallyn (serge-hallyn)]

Quoting Steve Langasek (<email address hidden>):
> On Wed, Mar 28, 2012 at 09:44:02PM -0000, Serge Hallyn wrote:
> > Since clearly it's too late to enable this feature in this cycle, do you
> > prefer that we explictly turn the support off in the builds for precise
> > immediately? Or simply wait until P+1 to enable it?
>
> I wouldn't worry for precise, and just enable it for Q.

Thanks, will do.

[Serge Hallyn (serge-hallyn)]

A candidate package is in ppa:serge-hallyn/virt and seems to work for me.