Re: [PATCH] KVM: arm64: Fix unaligned addr case in mmu walking

[Will Deacon]

On Wed, Mar 03, 2021 at 07:07:37PM +0000, Marc Zyngier wrote:
> From e0524b41a71e0f17d6dc8f197e421e677d584e72 Mon Sep 17 00:00:00 2001
> From: Jia He <justin.he@xxxxxxx>
> Date: Wed, 3 Mar 2021 10:42:25 +0800
> Subject: [PATCH] KVM: arm64: Fix range alignment when walking page tables
> 
> When walking the page tables at a given level, and if the start
> address for the range isn't aligned for that level, we propagate
> the misalignment on each iteration at that level.
> 
> This results in the walker ignoring a number of entries (depending
> on the original misalignment) on each subsequent iteration.
> 
> Properly aligning the address at the before the next iteration

"at the before the next" ???

> addresses the issue.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Howard Zhang <Howard.Zhang@xxxxxxx>
> Signed-off-by: Jia He <justin.he@xxxxxxx>
> Fixes: b1e57de62cfb ("KVM: arm64: Add stand-alone page-table walker infrastructure")
> [maz: rewrite commit message]
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/20210303024225.2591-1-justin.he@xxxxxxx
> ---
>  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 4d177ce1d536..124cd2f93020 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -223,7 +223,7 @@ static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data,
>  		goto out;
>  
>  	if (!table) {
> -		data->addr += kvm_granule_size(level);
> +		data->addr = ALIGN(data->addr, kvm_granule_size(level));
>  		goto out;
>  	}

If Jia is happy with it, please feel free to add:

Acked-by: Will Deacon <will@xxxxxxxxxx>

Will