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

Sebastian Ene
2025-01-14T15:03:42Z

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.

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

Cheers
Sebastian