[Xen-devel,v3,09/14] xen/x86: mm: Re-implement set_gpfn_from_mfn() as a static inline function

set_gpfn_from_mfn() is currently implement in a 2 part macros. The
second macro is only called within the first macro, so they can be
folded together.

Furthermore, this is now converted to a static inline making the code
more readable and safer.

As set_gpfn_from_mfn is now a static inline function, the extern
variable dom_cow should be defined earlier on. For convenience, the
definition of all dom_* variables are moved earlier on.

Signed-off-by: Julien Grall <julien.grall@arm.com>

---
    Changes in v3:
        - Add missing blank
        - Fix condition

    Changes in v2:
        - Patch added
---
 xen/include/asm-x86/mm.h | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

>>> On 03.06.19 at 18:03, <julien.grall@arm.com> wrote:
> --- a/xen/include/asm-x86/mm.h
> +++ b/xen/include/asm-x86/mm.h
> @@ -442,6 +442,8 @@ int check_descriptor(const struct domain *d, seg_desc_t *desc);
>  
>  extern paddr_t mem_hotplug;
>  
> +extern struct domain *dom_xen, *dom_io, *dom_cow;	/* for vmcoreinfo */

Ah, now I see what Andrew was talking about. In my patch, I'll move
the declarations ahead of the asm/mm.h inclusion point then.

> @@ -483,24 +485,25 @@ extern paddr_t mem_hotplug;
>  #define SHARED_M2P(_e)           ((_e) == SHARED_M2P_ENTRY)
>  
>  #define compat_machine_to_phys_mapping ((unsigned int 
> *)RDWR_COMPAT_MPT_VIRT_START)
> -#define _set_gpfn_from_mfn(mfn, pfn) ({                        \
> -    struct domain *d = page_get_owner(mfn_to_page(_mfn(mfn))); \
> -    unsigned long entry = (d && (d == dom_cow)) ?              \
> -        SHARED_M2P_ENTRY : (pfn);                              \
> -    ((void)((mfn) >= (RDWR_COMPAT_MPT_VIRT_END - RDWR_COMPAT_MPT_VIRT_START) / 4 || \
> -            (compat_machine_to_phys_mapping[(mfn)] = (unsigned int)(entry))), \
> -     machine_to_phys_mapping[(mfn)] = (entry));                \
> -    })
>  
>  /*
>   * Disable some users of set_gpfn_from_mfn() (e.g., free_heap_pages()) until
>   * the machine_to_phys_mapping is actually set up.
>   */
>  extern bool machine_to_phys_mapping_valid;
> -#define set_gpfn_from_mfn(mfn, pfn) do {        \
> -    if ( machine_to_phys_mapping_valid )        \
> -        _set_gpfn_from_mfn(mfn, pfn);           \
> -} while (0)
> +
> +static inline void set_gpfn_from_mfn(unsigned long mfn, unsigned long pfn)
> +{
> +    struct domain *d = page_get_owner(mfn_to_page(_mfn(mfn)));

const? And with that then
Reviewed-by: Jan Beulich <jbeulich@suse.com>

Jan

Hi Jan,

On 6/4/19 5:21 PM, Jan Beulich wrote:
>>>> On 03.06.19 at 18:03, <julien.grall@arm.com> wrote:
>> --- a/xen/include/asm-x86/mm.h
>> +++ b/xen/include/asm-x86/mm.h
>> @@ -442,6 +442,8 @@ int check_descriptor(const struct domain *d, seg_desc_t *desc);
>>   
>>   extern paddr_t mem_hotplug;
>>   
>> +extern struct domain *dom_xen, *dom_io, *dom_cow;	/* for vmcoreinfo */
> 
> Ah, now I see what Andrew was talking about. In my patch, I'll move
> the declarations ahead of the asm/mm.h inclusion point then.

Do you plan to merge your patch first? Just to know if I need to rebase.

> 
>> @@ -483,24 +485,25 @@ extern paddr_t mem_hotplug;
>>   #define SHARED_M2P(_e)           ((_e) == SHARED_M2P_ENTRY)
>>   
>>   #define compat_machine_to_phys_mapping ((unsigned int
>> *)RDWR_COMPAT_MPT_VIRT_START)
>> -#define _set_gpfn_from_mfn(mfn, pfn) ({                        \
>> -    struct domain *d = page_get_owner(mfn_to_page(_mfn(mfn))); \
>> -    unsigned long entry = (d && (d == dom_cow)) ?              \
>> -        SHARED_M2P_ENTRY : (pfn);                              \
>> -    ((void)((mfn) >= (RDWR_COMPAT_MPT_VIRT_END - RDWR_COMPAT_MPT_VIRT_START) / 4 || \
>> -            (compat_machine_to_phys_mapping[(mfn)] = (unsigned int)(entry))), \
>> -     machine_to_phys_mapping[(mfn)] = (entry));                \
>> -    })
>>   
>>   /*
>>    * Disable some users of set_gpfn_from_mfn() (e.g., free_heap_pages()) until
>>    * the machine_to_phys_mapping is actually set up.
>>    */
>>   extern bool machine_to_phys_mapping_valid;
>> -#define set_gpfn_from_mfn(mfn, pfn) do {        \
>> -    if ( machine_to_phys_mapping_valid )        \
>> -        _set_gpfn_from_mfn(mfn, pfn);           \
>> -} while (0)
>> +
>> +static inline void set_gpfn_from_mfn(unsigned long mfn, unsigned long pfn)
>> +{
>> +    struct domain *d = page_get_owner(mfn_to_page(_mfn(mfn)));
> 
> const? And with that then

Hmmm yes. I can't remember why I didn't do that before.

> Reviewed-by: Jan Beulich <jbeulich@suse.com>

Thank you!

Cheers,

>>> On 04.06.19 at 18:23, <julien.grall@arm.com> wrote:
> On 6/4/19 5:21 PM, Jan Beulich wrote:
>>>>> On 03.06.19 at 18:03, <julien.grall@arm.com> wrote:
>>> --- a/xen/include/asm-x86/mm.h
>>> +++ b/xen/include/asm-x86/mm.h
>>> @@ -442,6 +442,8 @@ int check_descriptor(const struct domain *d, seg_desc_t *desc);
>>>   
>>>   extern paddr_t mem_hotplug;
>>>   
>>> +extern struct domain *dom_xen, *dom_io, *dom_cow;	/* for vmcoreinfo */
>> 
>> Ah, now I see what Andrew was talking about. In my patch, I'll move
>> the declarations ahead of the asm/mm.h inclusion point then.
> 
> Do you plan to merge your patch first? Just to know if I need to rebase.

Well, that largely depends on having the necessary acks
(i.e. in particular yours for the Arm changes) in place. If I
had an Arm ack, the patch could go in right away (with the
adjustments made as requested by Andrew) afaict.

Jan