[PATCH 5/6 v5] kvm: booke: clear host tlb reference flag on guest tlb invalidation

[Bhushan Bharat-R65777]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Friday, September 20, 2013 11:38 PM
> To: Bhushan Bharat-R65777
> Cc: Wood Scott-B07421; benh at kernel.crashing.org; agraf at suse.de;
> paulus at samba.org; kvm at vger.kernel.org; kvm-ppc at vger.kernel.org; linuxppc-
> dev at lists.ozlabs.org
> Subject: Re: [PATCH 5/6 v5] kvm: booke: clear host tlb reference flag on guest
> tlb invalidation
> 
> On Fri, 2013-09-20 at 13:04 -0500, Bhushan Bharat-R65777 wrote:
> >
> > > -----Original Message-----
> > > From: Wood Scott-B07421
> > > Sent: Friday, September 20, 2013 9:48 PM
> > > To: Bhushan Bharat-R65777
> > > Cc: Wood Scott-B07421; benh at kernel.crashing.org; agraf at suse.de;
> > > paulus at samba.org; kvm at vger.kernel.org; kvm-ppc at vger.kernel.org;
> > > linuxppc- dev at lists.ozlabs.org
> > > Subject: Re: [PATCH 5/6 v5] kvm: booke: clear host tlb reference
> > > flag on guest tlb invalidation
> > >
> > > On Thu, 2013-09-19 at 23:19 -0500, Bhushan Bharat-R65777 wrote:
> > > > We uses these bit flags only for TLB1 and if size of stlbe is 4K
> > > > then we set E500_TLB_TLB0  otherwise we set E500_TLB_BITMAP.
> > > > Although I think that E500_TLB_BITMAP should be set only if stlbe
> > > > size is less than gtlbe size.
> > >
> > > Why?  Even if there's only one bit set in the map, we need it to
> > > keep track of which entry was used.
> >
> > If there is one entry then will not this be simple/faster to not lookup bitmap
> and guest->host array?
> > A flag indicate it is 1:1 map and this is physical address.
> 
> The difference would be negligible, and you'd have added overhead (both runtime
> and complexity) of making this a special case.

May be you are right , I will see if I can give a try :)
BTW I have already sent v6 of this patch.

-Bharat

> 
> -Scott
>