Kumar, Venkat
2008-Aug-28 05:50 UTC
[Xen-devel] HVM Domain Grant Reference For Sharing Memory
HVM need not execute a Hypercall to offer a page instead it will fill the appropriate grant reference structure inside the grant table from the obtained index in the grant table. But how will the HVM guest pass the grant reference to a PV guest so that he can map it. Is it through Xenstore? If it is through Xenstore, is there a hypercall involved? If it is not through Xenstore, is there any other way which is currently supported? Thx, Venkat _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jayaraman, Bhaskar
2008-Aug-28 06:03 UTC
[Xen-devel] RE: HVM Domain Grant Reference For Sharing Memory
Venkat, the Xenbus drivers haven''t been ported for HVM''s yet and I feel any out of band mechanism can be used to communicate the grant reference. Xenstore can be accessed through the store_mfn page passed to a PV but is unavailable to an HVM so you can''t write to the Xenstore from an HVM because neither the store_mfn nor the event channel is available there. Bhaskar. ________________________________ From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Kumar, Venkat Sent: Thursday, August 28, 2008 11:20 AM To: xen-devel@lists.xensource.com Subject: [Xen-devel] HVM Domain Grant Reference For Sharing Memory HVM need not execute a Hypercall to offer a page instead it will fill the appropriate grant reference structure inside the grant table from the obtained index in the grant table. But how will the HVM guest pass the grant reference to a PV guest so that he can map it. Is it through Xenstore? If it is through Xenstore, is there a hypercall involved? If it is not through Xenstore, is there any other way which is currently supported? Thx, Venkat _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2008-Aug-28 07:01 UTC
Re: [Xen-devel] RE: HVM Domain Grant Reference For Sharing Memory
Xenbus drivers are available for Linux (see unmodified_drivers/ subdirectory of the xen mercurial repository) and for Windows (see James Harper¹s GPLPV Windows work). -- Keir On 28/8/08 07:03, "Jayaraman, Bhaskar" <Bhaskar.Jayaraman@lsi.com> wrote:> Venkat, the Xenbus drivers haven¹t been ported for HVM¹s yet and I feel any > out of band mechanism can be used to communicate the grant reference. Xenstore > can be accessed through the store_mfn page passed to a PV but is unavailable > to an HVM so you can¹t write to the Xenstore from an HVM because neither the > store_mfn nor the event channel is available there. > Bhaskar. > > > > From: xen-devel-bounces@lists.xensource.com > [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Kumar, Venkat > Sent: Thursday, August 28, 2008 11:20 AM > To: xen-devel@lists.xensource.com > Subject: [Xen-devel] HVM Domain Grant Reference For Sharing Memory > > HVM need not execute a Hypercall to offer a page instead it will fill the > appropriate grant reference structure inside the grant table from the obtained > index in the grant table. > But how will the HVM guest pass the grant reference to a PV guest so that he > can map it. > Is it through Xenstore? > If it is through Xenstore, is there a hypercall involved? > If it is not through Xenstore, is there any other way which is currently > supported? > > > Thx, > Venkat > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel