Re: [PATCH for 4.20? v4 1/3] xen/riscv: implement software page table walking

[Jan Beulich <jbeulich@xxxxxxxx>]

On 12.02.2025 17:50, Oleksii Kurochko wrote:
> --- a/xen/arch/riscv/pt.c
> +++ b/xen/arch/riscv/pt.c
> @@ -185,6 +185,68 @@ static int pt_next_level(bool alloc_tbl, pte_t **table, 
> unsigned int offset)
>      return XEN_TABLE_NORMAL;
>  }
>  
> +/*
> + * _pt_walk() performs software page table walking and returns the pte_t of
> + * a leaf node or the leaf-most not-present pte_t if no leaf node is found
> + * for further analysis.
> + *
> + * Additionally, _pt_walk() returns the level of the found pte by using
> + * `pte_level` argument.
> + * `pte_level` is optional, set `pte_level`=NULL if a caller doesn't need
> + * the level of the found pte.

How about this, reducing redundancy a little?

 * _pt_walk() can optionally return the level of the found pte. Pass NULL
 * for `pte_level` if this information isn't needed.

> +pte_t pt_walk(vaddr_t va, unsigned int *pte_level)
> +{
> +    pte_t *entry = _pt_walk(va, pte_level);
> +    pte_t pte = *entry;
> +
> +    unmap_table(entry);
> +
> +    return pte;
> +}

"entry" especially in this context is ambiguous. I would expect a variable of
this name to be of type pte_t, not pte_t *. How about "ptep"?

Preferably with these adjustments, which I'd be fine making while committing,
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Considering the 4.20? tag you'll need to decide whether you still want this
in before the release.

Jan