[Qemu-devel] Re: Access to the host filesystem

[Matt Howard <mhoward@sigins.com>]

Fabrice Bellard wrote:

> Hi,
> 
> I wonder what would be the best way to access to the host filesystem,
> especially with the Linux, MSDOS/FreeDos and Windows guest OSes.
> 
> Here are my thoughts:
> 
> 1) Do nothing and just use the network with NFS or Samba host servers.
> It is the easiest solution but it requires a complicated host and guest
> configuration.
> 
> 2) Add a hardware device in QEMU giving access to the host filesystem
> with specific commands such as "open", "read" and "close" working by
> using DMA in physical guest memory. Then by reusing the user mode Linux
> "hostfs" filesystem, it would be easy to add access to the host
> filesystem. By reusing the dosemu "MFS" driver, it would also be
> possible to do the same as dosemu to access to an host DOS tree.
> 
> 3) Add a tiny NFS server in QEMU so that no host configuration is
> needed. Then only NFS drivers are needed in the guest OS.
> 
> Any comments ?
> 
> Fabrice.

I'd stick with Option 1.  2 and 3 are most heinously hackish, and won't
provide the user/operator with as many options.  2 only covers Linux and
DOS out of the box, and we all know how easy it is to get OSS developers to
work on windows drivers. ;)  3 sounds workable, except that the MS OSes
only support NFS through add-ons.  95% of qemu users will want network
connections to the guest anyway, so I'd say it's safe to assume that
they'll have it set up.  Maybe someone could write up a document for
post-networking setup that describes how to set up NFS/Samba in a
locked-down, local-only configuration.  This way, the job for you is
basically done. :)

-- 
Matt Howard <mhoward@sigins.com>
Superior Insurance - Technical Services