Re: [Xen-devel] Virtualization project idea

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Fri, Aug 27, 2010 at 06:16:32PM +0530, Dhananjay Goel wrote:
>    How are you sharing USB flash drives with physical machines
>    Comment: In ubuntu, plug in flash drive and access /media folder. Then
>    right click and click on "Sharing Options". Once you share it and give
>    others the right to add/edit the files, they can do so.
> 

That's NOT USB sharing at all! 
That's just a general filesystem share (nfs,cifs,whatever network share).

You can do that with Xen, over the network, just like with physical machines.

-- Pasi

>    Thanks,
>    Dhananjay
> 
>    On Fri, Aug 27, 2010 at 5:24 PM, Pasi K*rkk*inen <[1]pasik@xxxxxx> wrote:
> 
>      On Fri, Aug 27, 2010 at 04:56:33PM +0530, Dhananjay Goel wrote:
>      > * *Also you wouldn't see the changes made in other VMs,
>      > * *unless you made sure all the caches are refreshed etc in the VM all
>      the
>      > * *time.
>      >
>      > * *You'd need to use some cluster-filesystem (GFS, GFS2, OCFS2, GPFS,
>      etc).
>      > * *--Can you please suggest how NFS manages this because this case is
>      handled
>      > * *by NFS without any corruption?
>      > * *We can share flash drive across VMs as we do with physical machines
>      in
>      > * *LAN. Please help!
>      >
> 
>      How are you sharing USB flash drives with physical machines?
> 
>      -- Pasi
> 
>      > * *Thanks,
>      > * *Dhananjay
>      >
>      > * *On Fri, Aug 27, 2010 at 4:27 PM, Pasi K*rkk*inen
>      <[1][2]pasik@xxxxxx> wrote:
>      >
>      > * * *On Fri, Aug 27, 2010 at 02:53:54PM +0530, Dhananjay Goel wrote:
>      > * * *> * *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.
>      > * * *>
>      >
>      > * * *Because USB level has no idea about filesystems or files, or
>      locking
>      > * * *them!
>      >
>      > * * *Say you're using ext3 or NTFS in the VM for the USB device.
>      > * * *Those filesystems are NOT cluster-aware, ie. they're not aware of
>      any
>      > * * *sharing,
>      > * * *and they don't support any kind of sharing.
>      >
>      > * * *They expect exclusive access to the device.
>      >
>      > * * *If suddenly the bits on the device change from outside,
>      > * * *the filesystem gets corrupted very easily.
>      >
>      > * * *Also you wouldn't see the changes made in other VMs,
>      > * * *unless you made sure all the caches are refreshed etc in the VM
>      all the
>      > * * *time.
>      >
>      > * * *You'd need to use some cluster-filesystem (GFS, GFS2, OCFS2,
>      GPFS, etc).
>      >
>      > * * *-- Pasi
>      >
>      > * * *> * *Thanks,
>      > * * *> * *Dhananjay
>      > * * *>
>      > * * *> * *On Fri, Aug 27, 2010 at 2:49 PM, Pasi K*rkk*inen
>      > * * *<[1][2][3]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:
>      [2][3][4]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 K*rkk*inen
>      > * * *> * * *<[1][3][4][5]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][4][5][6]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][5][6][7]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][6][7][8]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * * *> * * *> * * *> * *2.
>      mailto:[5][7][8][9]james.harper@xxxxxxxxxxxxxxxx
>      > * * *> * * *>
>      > * * *> * * *> References
>      > * * *> * * *>
>      > * * *> * * *> * *Visible links
>      > * * *> * * *> * *1. mailto:[8][9][10]pasik@xxxxxx
>      > * * *> * * *> * *2.
>      > * * *[9][10][11]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * * *> * * *> * *3. mailto:[10][11][12]james.harper@xxxxxxxxxxxxxxxx
>      > * * *> * * *> * *4.
>      > * * *[11][12][13]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * * *> * * *> * *5. mailto:[12][13][14]james.harper@xxxxxxxxxxxxxxxx
>      > * * *>
>      > * * *> References
>      > * * *>
>      > * * *> * *Visible links
>      > * * *> * *1. mailto:[14][15]pasik@xxxxxx
>      > * * *> * *2.
>      [15][16]http://wiki.xensource.com/xenwiki/XenVGAPassthrough
>      > * * *> * *3. mailto:[16][17]pasik@xxxxxx
>      > * * *> * *4.
>      [17][18]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * * *> * *5. mailto:[18][19]james.harper@xxxxxxxxxxxxxxxx
>      > * * *> * *6.
>      [19][20]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * * *> * *7. mailto:[20][21]james.harper@xxxxxxxxxxxxxxxx
>      > * * *> * *8. mailto:[21][22]pasik@xxxxxx
>      > * * *> * *9.
>      [22][23]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * * *> * 10. mailto:[23][24]james.harper@xxxxxxxxxxxxxxxx
>      > * * *> * 11.
>      [24][25]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * * *> * 12. mailto:[25][26]james.harper@xxxxxxxxxxxxxxxx
>      >
>      > References
>      >
>      > * *Visible links
>      > * *1. mailto:[27]pasik@xxxxxx
>      > * *2. mailto:[28]pasik@xxxxxx
>      > * *3. [29]http://wiki.xensource.com/xenwiki/XenVGAPassthrough
>      > * *4. mailto:[30]pasik@xxxxxx
>      > * *5. [31]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * *6. mailto:[32]james.harper@xxxxxxxxxxxxxxxx
>      > * *7. [33]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * *8. mailto:[34]james.harper@xxxxxxxxxxxxxxxx
>      > * *9. mailto:[35]pasik@xxxxxx
>      > * 10. [36]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * 11. mailto:[37]james.harper@xxxxxxxxxxxxxxxx
>      > * 12. [38]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * 13. mailto:[39]james.harper@xxxxxxxxxxxxxxxx
>      > * 14. mailto:[40]pasik@xxxxxx
>      > * 15. [41]http://wiki.xensource.com/xenwiki/XenVGAPassthrough
>      > * 16. mailto:[42]pasik@xxxxxx
>      > * 17. [43]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * 18. mailto:[44]james.harper@xxxxxxxxxxxxxxxx
>      > * 19. [45]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * 20. mailto:[46]james.harper@xxxxxxxxxxxxxxxx
>      > * 21. mailto:[47]pasik@xxxxxx
>      > * 22. [48]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * 23. mailto:[49]james.harper@xxxxxxxxxxxxxxxx
>      > * 24. [50]http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>      > * 25. mailto:[51]james.harper@xxxxxxxxxxxxxxxx
> 
> References
> 
>    Visible links
>    1. mailto:pasik@xxxxxx
>    2. mailto:pasik@xxxxxx
>    3. mailto:pasik@xxxxxx
>    4. http://wiki.xensource.com/xenwiki/XenVGAPassthrough
>    5. mailto:pasik@xxxxxx
>    6. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>    7. mailto:james.harper@xxxxxxxxxxxxxxxx
>    8. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>    9. mailto:james.harper@xxxxxxxxxxxxxxxx
>   10. mailto:pasik@xxxxxx
>   11. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   12. mailto:james.harper@xxxxxxxxxxxxxxxx
>   13. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   14. mailto:james.harper@xxxxxxxxxxxxxxxx
>   15. mailto:pasik@xxxxxx
>   16. http://wiki.xensource.com/xenwiki/XenVGAPassthrough
>   17. mailto:pasik@xxxxxx
>   18. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   19. mailto:james.harper@xxxxxxxxxxxxxxxx
>   20. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   21. mailto:james.harper@xxxxxxxxxxxxxxxx
>   22. mailto:pasik@xxxxxx
>   23. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   24. mailto:james.harper@xxxxxxxxxxxxxxxx
>   25. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   26. mailto:james.harper@xxxxxxxxxxxxxxxx
>   27. mailto:pasik@xxxxxx
>   28. mailto:pasik@xxxxxx
>   29. http://wiki.xensource.com/xenwiki/XenVGAPassthrough
>   30. mailto:pasik@xxxxxx
>   31. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   32. mailto:james.harper@xxxxxxxxxxxxxxxx
>   33. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   34. mailto:james.harper@xxxxxxxxxxxxxxxx
>   35. mailto:pasik@xxxxxx
>   36. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   37. mailto:james.harper@xxxxxxxxxxxxxxxx
>   38. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   39. mailto:james.harper@xxxxxxxxxxxxxxxx
>   40. mailto:pasik@xxxxxx
>   41. http://wiki.xensource.com/xenwiki/XenVGAPassthrough
>   42. mailto:pasik@xxxxxx
>   43. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   44. mailto:james.harper@xxxxxxxxxxxxxxxx
>   45. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   46. mailto:james.harper@xxxxxxxxxxxxxxxx
>   47. mailto:pasik@xxxxxx
>   48. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   49. mailto:james.harper@xxxxxxxxxxxxxxxx
>   50. http://wiki.xensource.com/xenwiki/XenUSBPassthrough
>   51. mailto:james.harper@xxxxxxxxxxxxxxxx

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