---
title: "Share a Folder Between KVM Host and Guest"
tags:
date: "2012-09-11"
published: false
---

<! Share a Folder Between KVM Host and Guest >

<br>

I often find myself in situations where I need to share information
or files between a KVM host and KVM guest. With libvirt version 0.8.5
and newer there is support for mounting a
shared folder between a host and guest. I decided to try this out on
my Fedora 17 host, with a Fedora 17 guest. 

<br><br>

Using the libvirt
<a href="http://libvirt.org/formatdomain.html#elementsFilesystems">
<code>&ltfilesystem&gt</code>
</a>
xml tag I created the following xml that defines a <i>filesystem</i> device. 

<br><br>

<blockquote>
&ltfilesystem type='mount' accessmode='mapped'&gt
    &ltsource dir='/tmp/shared'/&gt
    &lttarget dir='tag'/&gt
&lt/filesystem&gt
</blockquote>

<br>

Note that target dir is not necessarily a mount point, but rather a
string that is exported to the guest that we will use when mounting in
the guest. 

<br><br>

In order to get this xml into the guest I had to use <code>virsh edit
F17</code> where F17 is the domain name of my guest. This opens the
guest xml in the VI text editor. I then inserted the xml at the end of
the <code>&ltdevices&gt</code>
section of the guest xml, closed VI, and started the guest. 

<br><br>

Once the guest had booted I used the following command to mount the
shared folder in the guest. 

<br><br>

<blockquote>
[root@F17 ~]# mount -t 9p -o trans=virtio,version=9p2000.L tag /mnt/shared/
</blockquote>

<br>

And voila! I can now access the /tmp/ directory of the host inside of
the guest. 

<br><br>

Note: I had some SELinux denials as a result of doing this. If I was
using this as a long term solution I would clean them up, but for now
I just disabled SELinux temporarily by using <code>sudo setenforce 0</code>
in the host. 

<br><br>
Resources:<br>
<a href="http://www.linux-kvm.org/page/9p_virtio">
http://www.linux-kvm.org/page/9p_virtio
</a><br>
<a href="http://wiki.qemu.org/Documentation/9psetup">
http://wiki.qemu.org/Documentation/9psetup
</a><br>
<a href="http://libvirt.org/formatdomain.html#elementsFilesystems">
http://libvirt.org/formatdomain.html#elementsFilesystems
</a><br>