WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] SCSI passthrough using /dev/sgX

hi
does SCSI passthrough need hardware support ,such as VT-d, or not?if there are two device and two VMs, does it need VT-d support, or not ? can it run in PVmode or have to run in HVM mode?

Thanks in advance


Mark Williamson 写道:
There are some folks (from Fujitsu? I think?) who are working on front/back-based SCSI passthrough. Patches have been submitted several times but not merged yet. They'll be in the list archives...

I don't think they've done a Windows frontend though ;-)

Cheers,
Mark

On Tuesday 04 December 2007, James Harper wrote:
Is anyone working on SCSI passthrough using the 'SCSI Generic' support
under Linux, eg /dev/sgX? This is how VMWare allows a VM to use SCSI
devices.
I assume that the lack of response means 'no'.

I've just been having a look through the documentation for 'SCSI
Generic' under Linux, and it looks pretty straightforward...

It could be done much like the existing blkdev interface, the 'input'
half of the sg_io_hdr (or something like it), would go on the ring as
the request, and the 'output' half, would come back on the ring as the
response. Buffers would be passed like the block interface does now,
although I'd probably prefer that we allow single byte aligned rather
than 512 byte aligned buffers as the block device currently does, as
Windows tends to use the former a bit. I'm not sure if any other IOCTL's
apart from SG_IO (which is the equivalent of a write + read operation
anyway) would be required as part of normal IO, they could just be
performed at initialisation and written to xenstore.

This would allow single SCSI devices or pretty much any type to be
exported to domains.

I'm interested in writing the Linux backend, and the Windows front end
as I'm pretty desperate for tape drive passthrough...

Comments?

Thanks

James


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel





_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel