Re: [PATCH] kvm: arm64: Properly align the end address of table walk

[Will Deacon]

On Fri, Jan 15, 2021 at 05:53:07PM +0800, Keqian Zhu wrote:
> When align the end address, ought to use its original value.
> 
> Fixes: b1e57de62cfb ("KVM: arm64: Add stand-alone page-table walker infrastructure")
> Signed-off-by: Keqian Zhu <zhukeqian1@xxxxxxxxxx>
> ---
>  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 bdf8e55ed308..670b0ef12440 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -296,7 +296,7 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
>  	struct kvm_pgtable_walk_data walk_data = {
>  		.pgt	= pgt,
>  		.addr	= ALIGN_DOWN(addr, PAGE_SIZE),
> -		.end	= PAGE_ALIGN(walk_data.addr + size),
> +		.end	= PAGE_ALIGN(addr + size),
>  		.walker	= walker,

Hmm, this is a change in behaviour, no (consider the case where both 'addr'
and 'size' are misaligned)? The current code is consistent with the
kerneldoc in asm/kvm_pgtable.h, so I don't see the motivation to change it.

Did you hit a bug somewhere?

Will