Re: [PATCH V3 05/10] xen/arm: static memory initialization

From: Jan Beulich <jbeulich@suse.com>
To: Penny Zheng <penny.zheng@arm.com>
Cc: Bertrand.Marquis@arm.com, Wei.Chen@arm.com, nd@arm.com,
	xen-devel@lists.xenproject.org, sstabellini@kernel.org,
	julien@xen.org
Subject: Re: [PATCH V3 05/10] xen/arm: static memory initialization
Date: Mon, 19 Jul 2021 10:25:18 +0200	[thread overview]
Message-ID: <b2ef39b8-4bdd-6d50-0c6b-a44fdf0608e3@suse.com> (raw)
In-Reply-To: <20210715051819.3073628-6-penny.zheng@arm.com>

On 15.07.2021 07:18, Penny Zheng wrote:
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -1519,6 +1519,26 @@ static void free_heap_pages(
>      spin_unlock(&heap_lock);
>  }
>  
> +#ifdef CONFIG_STATIC_MEMORY
> +/* Equivalent of free_heap_pages to free nr_mfns pages of static memory. */
> +void __init free_staticmem_pages(struct page_info *pg, unsigned long nr_mfns,
> +                                 bool need_scrub)
> +{
> +    mfn_t mfn = page_to_mfn(pg);
> +    unsigned long i;
> +
> +    for ( i = 0; i < nr_mfns; i++ )
> +    {
> +        mark_page_free(&pg[i], mfn_add(mfn, i));
> +
> +        if ( need_scrub )
> +        {
> +            /* TODO: asynchronous scrubbing for pages of static memory. */
> +            scrub_one_page(pg);
> +        }
> +    }
> +}
> +#endif

Btw, I think the lack of locking warrants extending the comment above
the function, to spell out what the implications are (in particular:
calls here need to happen early enough).

Jan