From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yang Hongyang <yanghy@cn.fujitsu.com>
Subject: Re: [PATCH v2 COLOPre 09/13] tools/libxl: Update
 libxl_save_msgs_gen.pl to support return data from xl to xc
Date: Tue, 16 Jun 2015 22:19:03 +0800
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To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: wei.liu2@citrix.com, ian.campbell@citrix.com, wency@cn.fujitsu.com, andrew.cooper3@citrix.com, yunhong.jiang@intel.com, eddie.dong@intel.com, xen-devel@lists.xen.org, guijianfeng@cn.fujitsu.com, rshriram@cs.ubc.ca
List-Id: xen-devel@lists.xenproject.org

Hi Ian,

On 06/16/2015 07:05 PM, Ian Jackson wrote:
> Yang Hongyang writes ("[Xen-devel] [PATCH v2 COLOPre 09/13] tools/libxl: Update libxl_save_msgs_gen.pl to support return data from xl to xc"):
>> From: Wen Congyang <wency@cn.fujitsu.com>
>>
>>   Currently, all callbacks return an integer value or void. We cannot
>>   return some data to xc via callback. Update libxl_save_msgs_gen.pl
>>   to support this case.
>
> Thanks for this.  I would have some comments on the details, but first
> I want to properly understand your use case.  So while I'm the author
> and maintainer of this save helper, I won't review this in detail just
> yet.  I'm following the thread about what this is for...

We need to send secondary's dirty page pfn back to primary. Primary will
then send pages that are both dirtied on primary/secondary to secondary.
in this way the secondary's memory will be consistent with primary.

As we disscussed in [PATCH v2 COLOPre 04/13] tools/libxc: export xc_bitops.h
If we move this operation to libxc layer, this patch could be dropped.

>
> Thanks,
> Ian.
> .
>

-- 
Thanks,
Yang.