Re: [PATCH v2 06/10] xen/arm: Retrieve p2m type in get_page_from_gfn

[Julien Grall <julien.grall@linaro.org>]

On 12/09/2013 04:58 PM, Ian Campbell wrote:
> On Mon, 2013-12-09 at 16:50 +0000, Julien Grall wrote:
>> On 12/09/2013 04:06 PM, Ian Campbell wrote:
>>> On Mon, 2013-12-09 at 03:34 +0000, Julien Grall wrote:
>>>> Signed-off-by: Julien Grall <julien.grall@linaro.org>
>>>>
>>>> ---
>>>>      Changes in v2:
>>>>          - Use p2m_lookup as p2m_get_entry was removed
>>>> ---
>>>>   xen/include/asm-arm/p2m.h |    3 ++-
>>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
>>>> index f4bcd7d..b63204d 100644
>>>> --- a/xen/include/asm-arm/p2m.h
>>>> +++ b/xen/include/asm-arm/p2m.h
>>>> @@ -109,7 +109,8 @@ static inline struct page_info *get_page_from_gfn(
>>>>       struct domain *d, unsigned long gfn, p2m_type_t *t, p2m_query_t q)
>>>>   {
>>>>       struct page_info *page;
>>>> -    unsigned long mfn = gmfn_to_mfn(d, gfn);
>>>> +    paddr_t maddr = p2m_lookup(d, pfn_to_paddr(gfn), t);
>>>> +    unsigned long mfn = maddr >> PAGE_SHIFT;
>>>
>>> I think this resend happened before I replied to the original a second
>>> time, (in <1386583029.13126.13.camel@kazak.uk.xensource.com>) so you
>>> hadn't seen it.
>>
>> Indeed, I will fix it.
>>
>>> TL;DR: INVALID_MADDR >> PAGE_SHIFT != INVALID_MFN on arm64.
>>
>> Does it mean that INVALID_MFN can be a valid mfn on arm64? If so, we
>> have some place in common code where this constant is used (see
>> common/domain.c for instance).
>
> No, INVALID_MFN is 0xffffffffffffffff which is fine[0].
>
> But given INVALID_MADDR of 0xffffffffffffffff,
> (INVALID_MADDR>>PAGE_SHIFT) is 0x000fffffffffffff.

oh right, I didn't pay attention for that. The patch is now fixed.

-- 
Julien Grall