Xen devel - Jan 2011 - vbd transfer limits

GPLPV provides access to vbd devices via scsiport. I''m writing a
storport driver now to resolve a couple of limitations under 2008 and
newer, and one of the notes says that a storport driver should support
buffers >64KB, but the vbd interface only supports a maximum of 40KB (10
* 4KB) bytes per transfer. If it turns out that this limit is a problem
I will need to break each windows SRB into multiple ring requests. As
long as I honour any write barrier requests from Windows, can anyone see
any problems with this?

Thanks

James

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James,

  We handle multiple requests per SRB in the Citrix PV drivers so I see no issue
with this.

  Paul
> -----Original Message-----
> From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel-
> bounces@lists.xensource.com] On Behalf Of James Harper
> Sent: 13 January 2011 14:52
> To: xen-devel@lists.xensource.com
> Subject: [Xen-devel] vbd transfer limits
> 
> GPLPV provides access to vbd devices via scsiport. I''m writing a
> storport driver now to resolve a couple of limitations under 2008
> and
> newer, and one of the notes says that a storport driver should
> support
> buffers >64KB, but the vbd interface only supports a maximum of 40KB
> (10
> * 4KB) bytes per transfer. If it turns out that this limit is a
> problem
> I will need to break each windows SRB into multiple ring requests.
> As
> long as I honour any write barrier requests from Windows, can anyone
> see
> any problems with this?
> 
> Thanks
> 
> James
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
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