linux-kernel - Re: [PATCH 4/6] kvm/x86/mmu: handle invlpg on large pages

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Date:	Fri, 6 Mar 2009 14:06:05 +0100
From:	Joerg Roedel <joerg.roedel@....com>
To:	Marcelo Tosatti <mtosatti@...hat.com>
CC:	Avi Kivity <avi@...hat.com>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/6] kvm/x86/mmu: handle invlpg on large pages

On Thu, Mar 05, 2009 at 06:11:22PM -0300, Marcelo Tosatti wrote:
> On Thu, Mar 05, 2009 at 01:12:31PM +0100, Joerg Roedel wrote:
> > Signed-off-by: Joerg Roedel <joerg.roedel@....com>
> > ---
> >  arch/x86/kvm/paging_tmpl.h |   12 +++++++++---
> >  1 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> > index 79668ba..aa79396 100644
> > --- a/arch/x86/kvm/paging_tmpl.h
> > +++ b/arch/x86/kvm/paging_tmpl.h
> > @@ -441,6 +441,7 @@ out_unlock:
> >  static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
> >  {
> >  	struct kvm_shadow_walk_iterator iterator;
> > +	struct kvm_mmu_page *sp;
> >  	pt_element_t gpte;
> >  	gpa_t pte_gpa = -1;
> >  	int level;
> > @@ -451,12 +452,17 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
> >  	for_each_shadow_entry(vcpu, gva, iterator) {
> >  		level = iterator.level;
> >  		sptep = iterator.sptep;
> > +		sp = page_header(__pa(sptep));
> > +
> > +		if (sp->role.direct) {
> > +			/* mapped from a guest's large_pte */
> > +			kvm_mmu_zap_page(vcpu->kvm, sp);
> > +			kvm_flush_remote_tlbs(vcpu->kvm);
> > +			return;
> > +		}
> 
> If the guest has 32-bit pte's there might be:
> 
> - two large shadow entries to cover 4MB
> - one large shadow entry and one shadow page with 512 4k entries
> - two shadow pages with 512 4k entries each
> 
> So need to cover all this cases.

Right. Thanks for pointing this out. I will post an updated version of
this patch.

	Joerg

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