On Fri, Apr 21, 2023 at 10:28:58AM +0100, Marc Zyngier wrote:
[...]
> So my conclusion is that after these two patches, data->phys should
> never be updated, right?
Yep, that's the intention.
> Then I'd suggest an additional patch to constify a couple of things
> and make sure we don't accidentally update them. Something like the
> patch below (compile-tested only).
I'm always a fan of more idiot proofing, especially when I am said idiot
:)
> From a2eb08ce793c1cf01c79df13a619815e9d7c1d41 Mon Sep 17 00:00:00 2001
> From: Marc Zyngier <maz@xxxxxxxxxx>
> Date: Fri, 21 Apr 2023 10:18:34 +0100
> Subject: [PATCH] KVM: arm64: Constify start/end/phys fields of the pgtable
> walker data
>
> As we are revamping the way the pgtable walker evaluates some of the
> data, make it clear that we rely on somew of the fields to be constant
> across the lifetime of a walk.
>
> For this, flag the start, end and pjys fields of the walk data as
typo: phys
> 'const', which will generate an error if we were to accidentally
> update these fields again.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Looks good.
Reviewed-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Let's see if I've confused b4 into thinking I'm reviewing my own patches
:-P
> ---
> arch/arm64/kvm/hyp/pgtable.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index 356a3fd5220c..5282cb9ca4cf 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -58,9 +58,9 @@
> struct kvm_pgtable_walk_data {
> struct kvm_pgtable_walker *walker;
>
> - u64 start;
> + const u64 start;
> u64 addr;
> - u64 end;
> + const u64 end;
> };
>
> static bool kvm_phys_is_valid(u64 phys)
> @@ -352,7 +352,7 @@ int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
> }
>
> struct hyp_map_data {
> - u64 phys;
> + const u64 phys;
> kvm_pte_t attr;
> };
>
> @@ -578,7 +578,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
> }
>
> struct stage2_map_data {
> - u64 phys;
> + const u64 phys;
> kvm_pte_t attr;
> u8 owner_id;
>
> --
> 2.34.1
>
> --
> Without deviation from the norm, progress is not possible.
--
Thanks,
Oliver
