Re: [Xen-devel] Virtualization project idea

[Dhananjay Goel <dhananjaygoel123@xxxxxxxxx>]

This won't be straight forward. Think about USB memory/flash stick.
If every VM sees it, and simultaneously writes to it, the filesystem
in it will get corrupted immediately!

--Why would it get corrupted immediately. Might be we can just lock a specific file which is being edited? Please suggest.

Thanks,
Dhananjay

On Fri, Aug 27, 2010 at 2:49 PM, Pasi Kärkkäinen <pasik@xxxxxx> wrote:

On Fri, Aug 27, 2010 at 02:45:12PM +0530, Dhananjay Goel wrote:
>    No, that's not possible with pvusb. pvusb is for direct passthru to
>    one/single vm.
>    You'd need some filesystem share (cifs/nfs/whatnot) to make such sharing
>    possible.
>    Comments: Is it possible to share USB keyboard, USB mouse, USB modem, etc
>    across VMs i.e host and guest(s)? If we connect USB keyboard, is it
>    possible to use it in guests?
>

This is implemented in XCI (Xen Client Initiative), and there has been
some discussions how to get it traditional Xen, to help Xen VGA Passthrough usage.

See: http://wiki.xensource.com/xenwiki/XenVGAPassthrough

>    Also, is it possible for us to modify the device driver of USB 2.0 so that
>    all USB 2.0 devices are visible and can be used across all VMs? Please
>    suggest.
>

This won't be straight forward. Think about USB memory/flash stick.
If every VM sees it, and simultaneously writes to it, the filesystem
in it will get corrupted immediately!

USB Passthru cannot be used to 'share' devices, it's for giving one/single VM
direct access to the device.

-- Pasi

>    Thanks,
>    Dhananjay

>
>    On Fri, Aug 27, 2010 at 2:16 PM, Pasi Kärkkäinen <[1]pasik@xxxxxx> wrote:
>
>      On Fri, Aug 27, 2010 at 01:37:49PM +0530, Dhananjay Goel wrote:
>      >    Hi James/Pasi,
>      >    I had a look at

>      [1][2]http://wiki.xensource.com/xenwiki/XenUSBPassthrough

>      >    But I'm not sure if it supports sharing USB devices across VMs
>      (host and
>      >    guest) i.e. if I plug in a flash drive then it would detect in both
>      host
>      >    and guest and I'd be able edit files from all VMs rather than
>      mounting and
>      >    unmounting everytime from 1 VM to other.
>      >    Please let me know your thoughts on it.
>      >
>
>      No, that's not possible with pvusb. pvusb is for direct passthru to
>      one/single vm.
>      You'd need some filesystem share (cifs/nfs/whatnot) to make such sharing
>      possible.
>
>      -- Pasi
>      >    Thanks,
>      >    Dhananjay
>      >
>      >    On Fri, Aug 27, 2010 at 4:28 AM, James Harper

>      >    <[2][3]james.harper@xxxxxxxxxxxxxxxx> wrote:
>      >
>      >      > Hi there!
>      >      >
>      >      > First I'd like to say that XEN plaform is really cool and
>      awesome.
>      >      >
>      >      > I'm an engineering student and is searching for a feasible
>      project in
>      >      > virtualization. I'd like to know if its possible to share USB
>      devices
>      >      (flash
>      >      > drive, hard disk, mouse, keyboards etc) across guests and host
>      (VMs).
>      >      Also, do
>      >      > you have any idea to extend it? Or any innovative idea so that
>      we can
>      >      > implement it.
>      >      >
>      >      > I'd appreciate any help. Thanks in advance.
>      >      >
>      >
>      >      Further to what Pasi said, I have partially ported the backend
>      interface
>      >      and can hand you the code if you want. It's probable a bit stale
>      vs the
>      >      current kernels and leaks memory under some circumstances but is
>      >      probably better than starting from scratch.
>      >      James
>      >
>      > References
>      >
>      >    Visible links

>      >    1. [4]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      >    2. mailto:[5]james.harper@xxxxxxxxxxxxxxxx
>
> References
>
>    Visible links
>    1. mailto:pasik@xxxxxx

>    2. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>    3. mailto:james.harper@xxxxxxxxxxxxxxxx
>    4. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>    5. mailto:james.harper@xxxxxxxxxxxxxxxx

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