Re: [Xen-devel] [PATCH 1/7] xen: import new ring macros in ring.h

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

Hi Stefano,

On 08/03/17 00:12, Stefano Stabellini wrote:
> On Tue, 7 Mar 2017, Julien Grall wrote:
>> Hi Stefano,
>>
>> On 03/06/2017 08:01 PM, Stefano Stabellini wrote:
>>> Sync the ring.h file with upstream Xen, to introduce the new ring macros.
>>> They will be used by the Xen transport for 9pfs.
>>>
>>> Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
>>> CC: konrad.wilk@oracle.com
>>> CC: boris.ostrovsky@oracle.com
>>> CC: jgross@suse.com
>>>
>>> ---
>>> NB: The new macros have not been committed to Xen yet. Do not apply this
>>> patch until they do.
>>> ---
>>> ---
>>>  include/xen/interface/io/ring.h | 131
>>> ++++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 131 insertions(+)
>>>
>>> diff --git a/include/xen/interface/io/ring.h
>>> b/include/xen/interface/io/ring.h
>>> index 21f4fbd..e16aa92 100644
>>> --- a/include/xen/interface/io/ring.h
>>> +++ b/include/xen/interface/io/ring.h
>>
>> [...]
>>
>>> +#define XEN_FLEX_RING_SIZE(order)
>>> \
>>> +    (1UL << (order + PAGE_SHIFT - 1))
>>
>> This will need to be XEN_PAGE_SHIFT in order to works with 64K kernel.
>
> Good point! I had it right at the beginning but I lost the change in one
> of the updates from xen.git.

It is probably worth to consider introducing XEN_PAGE_SIZE in the 
hypervisor code because we are likely to miss the change when the 
headers will be re-sync in the future.

Cheers,

-- 
Julien Grall