From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v2 1/3] xen/domain_page: Convert
 map_domain_page_global() to using mfn_t
Date: Tue, 7 Jul 2015 11:07:26 +0100
Message-ID: <559BA4DE.5000507@citrix.com>
References: <1435838656-9219-1-git-send-email-Ben.Catterall@citrix.com>
	<559BBF80020000780008D42A@mail.emea.novell.com>
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To: Jan Beulich <JBeulich@suse.com>, Ben Catterall <Ben.Catterall@citrix.com>
Cc: xen-devel@lists.xenproject.org, keir@xen.org, stefano.stabellini@citrix.com, ian.campbell@citrix.com, tim@xen.org
List-Id: xen-devel@lists.xenproject.org

On 07/07/15 11:01, Jan Beulich wrote:
>>>> On 02.07.15 at 14:04, <Ben.Catterall@citrix.com> wrote:
>> --- a/xen/include/xen/domain_page.h
>> +++ b/xen/include/xen/domain_page.h
>> @@ -41,11 +41,15 @@ unsigned long domain_page_map_to_mfn(const void *va);
>>   * address spaces (not just within the VCPU that created the mapping). Global
>>   * mappings can also be unmapped from any context.
>>   */
>> -void *map_domain_page_global(unsigned long mfn);
>> +void *map_domain_page_global(mfn_t mfn);
>>  void unmap_domain_page_global(const void *va);
>>  
>>  #define __map_domain_page(pg)        map_domain_page(__page_to_mfn(pg))
>> -#define __map_domain_page_global(pg) map_domain_page_global(__page_to_mfn(pg))
>> +
>> +static inline void *__map_domain_page_global(struct page_info *pg)
> const
>
>> @@ -117,9 +121,17 @@ domain_mmap_cache_destroy(struct domain_mmap_cache *cache)
>>                                                        mfn_to_virt(smfn))
>>  #define domain_page_map_to_mfn(va)          virt_to_mfn((unsigned long)(va))
>>  
>> -#define map_domain_page_global(mfn)         mfn_to_virt(mfn)
>> -#define __map_domain_page_global(pg)        page_to_virt(pg)
>> -#define unmap_domain_page_global(va)        ((void)(va))
>> +static inline void *map_domain_page_global(mfn_t mfn)
>> +{
>> +    return mfn_to_virt(mfn_x(mfn));
>> +}
>> +
>> +static inline void *__map_domain_page_global(struct page_info *pg)
> const
>
>> +{
>> +    return page_to_virt(pg);
>> +}
>> +
>> +static inline void unmap_domain_page_global(void *va) {};
> And again (the more that the real function already has it that way).

Hmm.  Both unmap_domain_page() and _global() should be updated to not
take a const void *va.

Just like free(), these functions are not performing a read-only
operation on the destination pointer, therefore must not be performed on
an actual const pointer.

~Andrew