Re: [Xen-devel] [PATCH 5/6] xen: arm: add some helpers for assessing p2m pte

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 06/10/2014 12:46 PM, Ian Campbell wrote:
> On Tue, 2014-06-10 at 12:37 +0100, Julien Grall wrote:
>> On 06/10/2014 10:57 AM, Ian Campbell wrote:
>>>      mask = SECOND_MASK;
>>>      second = map_domain_page(pte.p2m.base);
>>>      pte = second[second_table_offset(paddr)];
>>> -    if ( !pte.p2m.valid || !pte.p2m.table )
>>> +    if ( !p2m_table(pte) )
>>>          goto done;
>>>  
>>>      mask = THIRD_MASK;
>>> @@ -156,11 +161,11 @@ paddr_t p2m_lookup(struct domain *d, paddr_t paddr, 
>>> p2m_type_t *t)
>>>      pte = third[third_table_offset(paddr)];
>>>  
>>>      /* This bit must be one in the level 3 entry */
>>> -    if ( !pte.p2m.table )
>>> +    if ( !p2m_table(pte) )
>>>          pte.bits = 0;
>>>  
>>>  done:
>>> -    if ( pte.p2m.valid )
>>> +    if ( p2m_valid(pte) )
>>
>> Regardless the current check, I think this should be p2m_entry(pte) to
>> help code comprehension.
>>
>> Indeed, the can only get the address if the pte is pointed to a memory
>> block.
> 
> Yes, but an L3 PTE has the table bit set, which would make
> p2m_entry(pte) false...

Hmmm... right. But this bit (ie table bit) doesn't have the same meaning
on L3. Your comment on p2m_table is confusing.

Anyway:

Acked-by: Julien Grall <julien.grall@xxxxxxxxxx>

-- 
Julien Grall

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