Ping²: [PATCH v2 1/3] x86/PoD: simplify / improve p2m_pod_cache_add()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 27.01.2022 16:04, Jan Beulich wrote:
> 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?

Another 4 weeks have passed ...

Thanks for feedback either way, Jan

>> --- 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. */
>>
>>
>