Re: linux PVH broken in 3.16.0-rc7 (arch_gnttab_map_shared)

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Aug 04, 2014 at 11:33:54AM +0100, David Vrabel wrote:
> On 02/08/14 00:46, Mukesh Rathor wrote:
> > Hi,
> > 
> > Not sure if this already got reported, but it appears 

No it has not. Thank you for reporting it!
> > 
> > commit b7dd0e3
> > Author: David Vrabel <david.vrabel@citrix.com>
> > Date:   Fri Jul 11 16:42:34 2014 +0100
> > 
> >     x86/xen: safely map and unmap grant frames when in atomic context
> > 
> > has broken boot of domU PVH. The reason being arch_gnttab_map_shared
> > is getting called before gnttab_shared_vm_area gets initialized by
> > arch_gnttab_init(). As the comment says,
> 
> Well that makes no sense since all those functions are PV only.  This
> patch did not change how PVH guests were initialized.

PVH is PV and HVM. It uses the same paths and then some! :-) See
6926f6d6109714aab7b26df7099b12555e36676f as the grant mechanism
is HVM. It could be reworked so that '__gnttab_init' ends up
calling xlated_setup_gnttab_pages?

Mukesh, the reason it did not get caught is that upstream Xen is
broken in as the libxl patch that Roger had posted has not yet
been committed. This is 'libxl: create PVH guests with max memory assigned'.

> 
> David
> 
> 
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