Re: [PATCH] xen/mm: Unmap page for direct mapped domain on decrease reservation

[Julien Grall <julien.grall@citrix.com>]

On 27/10/15 13:08, Jan Beulich wrote:
>> --- a/xen/common/memory.c
>> +++ b/xen/common/memory.c
>> @@ -257,8 +257,16 @@ int guest_remove_page(struct domain *d, unsigned long gmfn)
>>  
>>      if ( test_and_clear_bit(_PGT_pinned, &page->u.inuse.type_info) )
>>          put_page_and_type(page);
>> -            
>> -    if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
>> +
>> +    /*
>> +     * With the lack for iommu on some ARM platform, domain with DMA-capable
> 
> I think it's "lack of", and I also wonder whether calling out ARM here
> is really meaningful.
> 
>> +     * device must retrieve the same pfn when the hypercall populate_physmap
>> +     * is called.
>> +     *
>> +     * For this purpose, the page is kept allocated.
> 
> ..., to match populate_physmap() behavior. (or some such)

I saw that your already committed the patch. FWIW, I'm fine with both
changes.

Regards,

-- 
Julien Grall