From mboxrd@z Thu Jan  1 00:00:00 1970
From: George Dunlap <george.dunlap@citrix.com>
Subject: Re: [PATCH v3 3/3] tools: introduce parameter
 max_wp_ram_ranges.
Date: Mon, 22 Feb 2016 17:23:20 +0000
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To: Paul Durrant <Paul.Durrant@citrix.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Wei Liu <wei.liu2@citrix.com>, Ian Campbell <Ian.Campbell@citrix.com>, Andrew Cooper <Andrew.Cooper3@citrix.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Zhang Yu <yu.c.zhang@linux.intel.com>, Zhiyuan Lv <zhiyuan.lv@intel.com>, Jan Beulich <JBeulich@suse.com>, Ian Jackson <Ian.Jackson@citrix.com>, Stefano Stabellini <Stefano.Stabellini@citrix.com>, "Keir (Xen.org)" <keir@xen.org>
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On 22/02/16 17:01, Paul Durrant wrote:
>> What you did in an earlier version of this series (correct me if I'm
>> wrong) is to make a separate hypercall for memory, but still keep using
>> the same internal implementation (i.e., still having a write_dm p2m type
>> and using rangesets to determine which ioreq server to give the
>> notification to).  But since the interface for memory looks exactly the
>> same as the interface for MMIO, at some point this morphed back to "use
>> xen_hvm_io_range but with a different range type (i.e., WP_MEM)".
>>
> 
> Yes, and that's now pointless since we're going to use purely p2m types for sending memory accesses to ioreq servers.
> 
>> From an *interface* perspective that makes sense, because in both cases
>> you want to be able to specify a domain, an ioreq server, and a range of
>> physical addresses.  I don't have any objection to the change you made
>> to hvm_op.h in this version of the series.
>>
> 
> No, if we are intercepting 'memory' purely by p2m type then there is no need for the additional range type.

So here seems to be the crux of our disagreement.

I don't understand why you think that the WP_MEM interface described in
patch 2 of this series can't be implemented using p2m types rather than
rangesets.

 -George