Re: [Xen-devel] [PATCH v5 10/16] xen/mm: Switch map_pages_to_xen to use MFN typesafe

[George Dunlap <george.dunlap@xxxxxxxxxx>]

On 03/15/2018 04:53 PM, Julien Grall wrote:
> Hi George,
> 
> On 15/03/18 16:50, George Dunlap wrote:
>> On 03/14/2018 06:20 PM, julien.grall@xxxxxxx wrote:
>>> diff --git a/xen/common/vmap.c b/xen/common/vmap.c
>>> index 11785ffb0a..04f5db386d 100644
>>> --- a/xen/common/vmap.c
>>> +++ b/xen/common/vmap.c
>>> @@ -9,6 +9,10 @@
>>>   #include <xen/vmap.h>
>>>   #include <asm/page.h>
>>>   +/* Override macros from asm/page.h to make them work with mfn_t */
>>> +#undef page_to_mfn
>>> +#define page_to_mfn(pg) _mfn(__page_to_mfn(pg))
>>> +
>>>   static DEFINE_SPINLOCK(vm_lock);
>>>   static void *__read_mostly vm_base[VMAP_REGION_NR];
>>>   #define vm_bitmap(x) ((unsigned long *)vm_base[x])
>>> @@ -208,7 +212,7 @@ void *__vmap(const mfn_t *mfn, unsigned int
>>> granularity,
>>>         for ( ; va && nr--; ++mfn, cur += PAGE_SIZE * granularity )
>>>       {
>>> -        if ( map_pages_to_xen(cur, mfn_x(*mfn), granularity, flags) )
>>> +        if ( map_pages_to_xen(cur, *mfn, granularity, flags) )
>>>           {
>>>               vunmap(va);
>>>               va = NULL;
>>> @@ -234,7 +238,7 @@ void vunmap(const void *va)
>>>   #ifndef _PAGE_NONE
>>>       destroy_xen_mappings(addr, addr + PAGE_SIZE * pages);
>>>   #else /* Avoid tearing down intermediate page tables. */
>>> -    map_pages_to_xen(addr, 0, pages, _PAGE_NONE);
>>> +    map_pages_to_xen(addr, INVALID_MFN, pages, _PAGE_NONE);
>>
>> This is a bit of a nit-pick, but shouldn't something like this have gone
>> in patch 8?
> 
> patch #8 is about removing a parameter of populate_pt_range. At the same
> time, 0 is replaced by mfn_x(INVALID_MFN) for that specific use case.
> 
> It was not intended to replace all the user of map_pages_to_xen with 0
> to mfn_x(INVALID_MFN). This is done here as the caller is modified.

Fair enough:

Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>

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