Re: [PATCH] KVM: arm64: Fix the upper limit of the walker range

[Marc Zyngier <maz@kernel.org>]

On Tue, 14 Jan 2025 15:03:37 +0000,
Sebastian Ene <sebastianene@google.com> wrote:
> 
> On Tue, Jan 14, 2025 at 02:55:17PM +0000, Marc Zyngier wrote:
> > On Tue, 14 Jan 2025 14:50:51 +0000,
> > Sebastian Ene <sebastianene@google.com> wrote:
> > > 
> > > Prevent the walker from running into weeds when walking an
> > > entire address range.
> > > 
> > > Signed-off-by: Sebastian Ene <sebastianene@google.com>
> > > ---
> > >  arch/arm64/kvm/hyp/pgtable.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> > > index 40bd55966..2ffb5571e 100644
> > > --- a/arch/arm64/kvm/hyp/pgtable.c
> > > +++ b/arch/arm64/kvm/hyp/pgtable.c
> > > @@ -260,7 +260,7 @@ static int _kvm_pgtable_walk(struct kvm_pgtable *pgt, struct kvm_pgtable_walk_da
> > >  {
> > >  	u32 idx;
> > >  	int ret = 0;
> > > -	u64 limit = BIT(pgt->ia_bits);
> > > +	u64 limit = BIT(pgt->ia_bits) - 1;
> > >  
> > >  	if (data->addr > limit || data->end > limit)
> > >  		return -ERANGE;
> > 
> > Huh, nice catch. I guess this deserves a
> > 
> > Fixes: b1e57de62cfb4 ("KVM: arm64: Add stand-alone page-table walker infrastructure")
> > Cc: stable@vger.kernel.org
> > 
> > right?
> > 
> > 	M.
> 
> Hi Marc,
> 
> Thanks for the prompt review. Adding the missing bits now and re-spinnig
> v2.

Too late! ;-)

	M.

-- 
Without deviation from the norm, progress is not possible.