Ping: [PATCH v2 1/3] x86/PoD: simplify / improve p2m_pod_cache_add()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 04.01.2022 10:48, Jan Beulich wrote:
> Avoid recurring MFN -> page or page -> MFN translations. Drop the pretty
> pointless local variable "p". Make sure the MFN logged in a debugging
> error message is actually the offending one. Return negative errno
> values rather than -1 (presently no caller really cares, but imo this
> should change). Adjust style.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> v2: Return -errno. Drop exclamation mark from log message.

Ping?

> --- a/xen/arch/x86/mm/p2m-pod.c
> +++ b/xen/arch/x86/mm/p2m-pod.c
> @@ -58,34 +58,27 @@ p2m_pod_cache_add(struct p2m_domain *p2m
>                    unsigned int order)
>  {
>      unsigned long i;
> -    struct page_info *p;
>      struct domain *d = p2m->domain;
> +    mfn_t mfn = page_to_mfn(page);
>  
>  #ifndef NDEBUG
> -    mfn_t mfn;
> -
> -    mfn = page_to_mfn(page);
> -
>      /* Check to make sure this is a contiguous region */
>      if ( mfn_x(mfn) & ((1UL << order) - 1) )
>      {
>          printk("%s: mfn %lx not aligned order %u! (mask %lx)\n",
>                 __func__, mfn_x(mfn), order, ((1UL << order) - 1));
> -        return -1;
> +        return -EINVAL;
>      }
>  
> -    for ( i = 0; i < 1UL << order ; i++)
> +    for ( i = 0; i < (1UL << order); i++)
>      {
> -        struct domain * od;
> +        const struct domain *od = page_get_owner(page + i);
>  
> -        p = mfn_to_page(mfn_add(mfn, i));
> -        od = page_get_owner(p);
>          if ( od != d )
>          {
> -            printk("%s: mfn %lx expected owner d%d, got owner d%d!\n",
> -                   __func__, mfn_x(mfn), d->domain_id,
> -                   od ? od->domain_id : -1);
> -            return -1;
> +            printk("%s: mfn %lx owner: expected %pd, got %pd\n",
> +                   __func__, mfn_x(mfn) + i, d, od);
> +            return -EACCES;
>          }
>      }
>  #endif
> @@ -98,16 +91,12 @@ p2m_pod_cache_add(struct p2m_domain *p2m
>       * promise to provide zero pages. So we scrub pages before using.
>       */
>      for ( i = 0; i < (1UL << order); i++ )
> -        clear_domain_page(mfn_add(page_to_mfn(page), i));
> +        clear_domain_page(mfn_add(mfn, i));
>  
>      /* First, take all pages off the domain list */
>      lock_page_alloc(p2m);
> -    for ( i = 0; i < 1UL << order ; i++ )
> -    {
> -        p = page + i;
> -        page_list_del(p, &d->page_list);
> -    }
> -
> +    for ( i = 0; i < (1UL << order); i++ )
> +        page_list_del(page + i, &d->page_list);
>      unlock_page_alloc(p2m);
>  
>      /* Then add to the appropriate populate-on-demand list. */
> 
>