Re: [PATCH for-4.6] libxl: move calling libxl__arch_domain_construct_memmap to right place

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2015-08-05 at 11:58 +0100, Wei Liu wrote:
> On Wed, Aug 05, 2015 at 11:48:55AM +0100, Ian Campbell wrote:
> > On Wed, 2015-08-05 at 11:43 +0100, Wei Liu wrote:
> > > On Wed, Aug 05, 2015 at 11:38:54AM +0100, Ian Campbell wrote:
> > > > On Wed, 2015-08-05 at 11:23 +0100, Wei Liu wrote:
> > > > > This function was called in the wrong place, because both
> > > > > libxl__vnuma_build_vmemrange_hvm and xc_hvm_build rely on its 
> > > > > output.
> > > > 
> > > > What is the effect of this call being in the wrong place? 
> > > > Presumably 
> > > > one or
> > > > the other of those functions reaches the wrong conclusion?
> > > 
> > > Originally, by the time that function got called, all guest pages 
> > > were
> > > already populated.  The end result is E820 map disagrees with what 
> > > vNUMA
> > > says and what address ranges memory actually resides, i.e. risk of 
> > > guest
> > > accessing region that doesn't have backing pages.
> > 
> > Ouch. This should certainly be explained in the commit message.
> > 
> > With that: Acked-by: Ian Campbell <ian.campbell@citrix.com>
> > 
> 
> I will post v2 shortly with that information in commit message.
> 
> > Although perhaps we should wait for confirmation this fix doesn't 
> > regress
> > RMRR somehow?
> > 
> 
> I doubt it will. The code as-is is already broken for RMRR. But let's
> wait till tomorrow for Tiejun to reply.
> 
> If he doesn't reply by tomorrow, I suggest we apply v2 first and
> fix up any subsequent issues later.

Agreed.