> -----Original Message-----
> From: Alexander Graf [mailto:ag...@suse.de]
> Sent: Thursday, April 25, 2013 8:36 PM
> To: Bhushan Bharat-R65777
> Cc: kvm-ppc@vger.kernel.org; k...@vger.kernel.org; Wood Scott-B07421; Bhushan
> Bharat-R65777
> Subject: Re: [PATCH] KVM : PPC : cache flush for kernel managed pages
> 
> 
> On 23.04.2013, at 08:39, Bharat Bhushan wrote:
> 
> > Kernel should only try flushing pages which are managed by kernel.
> > pfn_to_page will returns junk struct page for pages not managed by
> > kernel, so if kernel will try to flush direct mapped memory or direct
> > assigned device mapping then it will work on junk struct page.
> >
> > Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com>
> > ---
> > arch/powerpc/kvm/e500_mmu_host.c |    3 ++-
> > 1 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/arch/powerpc/kvm/e500_mmu_host.c
> > b/arch/powerpc/kvm/e500_mmu_host.c
> > index 1c6a9d7..e07da21 100644
> > --- a/arch/powerpc/kvm/e500_mmu_host.c
> > +++ b/arch/powerpc/kvm/e500_mmu_host.c
> > @@ -455,7 +455,8 @@ static inline int kvmppc_e500_shadow_map(struct
> kvmppc_vcpu_e500 *vcpu_e500,
> >                             ref, gvaddr, stlbe);
> >
> >     /* Clear i-cache for new pages */
> > -   kvmppc_mmu_flush_icache(pfn);
> > +   if (pfn_valid(pfn))
> > +           kvmppc_mmu_flush_icache(pfn);
> 
> Could you please move the check into kvmppc_mmu_flush_icache()? That way we're
> guaranteed we can't screw up cache flushes ever :).
> 
> Also, please add a comment saying why we need this.

Ok

-Bharat

> 
> 
> Alex
> 
> >
> >     /* Drop refcount on page, so that mmu notifiers can clear it */
> >     kvm_release_pfn_clean(pfn);
> > --
> > 1.7.0.4
> >
> >
> 


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