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

Marc Zyngier
2025-01-14T15:08:39Z

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.

--
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