Re: [Xen-devel] Regressions in v3.3-rc1 introduced by"xen/granttable: Grant tables V2 implementation"

[Konrad Rzeszutek Wilk]

On Wed, Jan 25, 2012 at 03:23:28PM +0000, Paul Durrant wrote:
> > -----Original Message-----
> > From: Paul Durrant
> > Sent: 25 January 2012 07:17
> > To: Ian Campbell; Konrad Rzeszutek Wilk
> > Cc: annie.li@xxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx; linux-
> > kernel@xxxxxxxxxxxxxxx
> > Subject: RE: [Xen-devel] Regressions in v3.3-rc1 introduced by
> > "xen/granttable: Grant tables V2 implementation"
> > 
> > > -----Original Message-----
> > >
> > > On HVM for gnttab_shared we make an add_to_physmap call with
> > > XENMAPSPACE_grant_table (in gnttab_map). I don't see any support call
> > > to do something similar for the status array though and I don't see a
> > > XENMAPSPACE_* specifically for that case either in the hypervisor either.
> > >
> > 
> > There is no map-space for the status pages. To map them you use the
> > standard map space but OR a bit (top bit IIRC) into in the idx. It's a bit icky,
> > but that's how it is.
> > 
> 
> I fixed a bug in xen-unstable a few weeks back that prevented mapping of the status frames so I guess the bug is possibly due to trying to use gnttab 2 on 4.1, where this bug would hit, but failing to check the return code from the status mapping hypercall?

changeset:   24428:5b4b7e565ab8
user:        Paul Durrant <paul.durrant@xxxxxxxxxx>
date:        Sun Dec 18 14:39:14 2011 +0000
summary:     Fix grant_table v2 status mapping.

changeset:   24427:931bf1105730
user:        Paul Durrant <paul.durrant@xxxxxxxxxx>
date:        Sun Dec 18 14:38:32 2011 +0000
summary:     Allow VMs to query their own grant table version.


Looks like c/s 24427 needs to be in the hypervior. Hm, but that exists
in 4.1 too as 23204. Will try back-porting cs 24428 in Xen 4.1 and seeing
if that does it.
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