Re: [PATCH v10 3/6] x86/ioreq server: Add device model wrappers for new DMOP

From: Yu Zhang <yu.c.zhang@linux.intel.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Jackson <Ian.Jackson@citrix.com>,
	Paul Durrant <Paul.Durrant@citrix.com>,
	"zhiyuan.lv@intel.com" <zhiyuan.lv@intel.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH v10 3/6] x86/ioreq server: Add device model wrappers for new DMOP
Date: Wed, 5 Apr 2017 18:21:41 +0800	[thread overview]
Message-ID: <58E4C535.6010908@linux.intel.com> (raw)
In-Reply-To: <20170405102057.piu3b67uvib2tauv@citrix.com>

On 4/5/2017 6:20 PM, Wei Liu wrote:
> On Wed, Apr 05, 2017 at 11:08:46AM +0100, Wei Liu wrote:
>> On Wed, Apr 05, 2017 at 02:53:42PM +0800, Yu Zhang wrote:
>>>
>>> On 4/3/2017 5:28 PM, Wei Liu wrote:
>>>> On Mon, Apr 03, 2017 at 09:13:20AM +0100, Paul Durrant wrote:
>>>>>> -----Original Message-----
>>>>>> From: Yu Zhang [mailto:yu.c.zhang@linux.intel.com]
>>>>>> Sent: 02 April 2017 13:24
>>>>>> To: xen-devel@lists.xen.org
>>>>>> Cc: zhiyuan.lv@intel.com; Paul Durrant <Paul.Durrant@citrix.com>; Ian
>>>>>> Jackson <Ian.Jackson@citrix.com>; Wei Liu <wei.liu2@citrix.com>
>>>>>> Subject: [PATCH v10 3/6] x86/ioreq server: Add device model wrappers for
>>>>>> new DMOP
>>>>>>
>>>>>> A new device model wrapper is added for the newly introduced
>>>>>> DMOP - XEN_DMOP_map_mem_type_to_ioreq_server.
>>>>>>
>>>>>> Since currently this DMOP only supports the emulation of write
>>>>>> operations, attempts to trigger the DMOP with values other than
>>>>>> XEN_DMOP_IOREQ_MEM_ACCESS_WRITE or 0(to unmap the ioreq server)
>>>>>> shall fail. The wrapper shall be updated once read operations
>>>>>> are also to be emulated in the future.
>>>>>>
>>>>>> Also note currently this DMOP only supports one memory type,
>>>>>> and can be extended in the future to map multiple memory types
>>>>>> to multiple ioreq servers, e.g. mapping HVMMEM_ioreq_serverX to
>>>>>> ioreq server X, This wrapper shall be updated when such change
>>>>>> is made.
>>>>>>
>>>>>> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
>>>>> Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
>>>>>
>>>>> ...with one observation...
>>>>>
>>>>>> ---
>>>>>> Cc: Paul Durrant <paul.durrant@citrix.com>
>>>>>> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
>>>>>> Cc: Wei Liu <wei.liu2@citrix.com>
>>>>>> ---
>>>>>>    tools/libs/devicemodel/core.c                   | 25
>>>>>> +++++++++++++++++++++++++
>>>>>>    tools/libs/devicemodel/include/xendevicemodel.h | 18
>>>>>> ++++++++++++++++++
>>>>>>    tools/libs/devicemodel/libxendevicemodel.map    |  1 +
>>>>>>    tools/libxc/include/xenctrl_compat.h            |  5 +++++
>>>>>>    tools/libxc/xc_devicemodel_compat.c             | 17 +++++++++++++++++
>>>>> This is new code so I don't think you really want compat code for this, do you?
>>>> Correct. No compat code is needed.
>>> Thank you, Paul & Wei.
>>> Oh. I see, the compat code is only for existing ones. We do not need this.
>>> What about the libxendevicemodel.map? I updated this file to build pass for
>>> the libxc, with compat code
>>> not changed, maybe we shall not add the new op to libxendevicemodel.map
>>> either.
>>>
>> The modification to libxendevicemodel.map needs to stay.
>>
> And, if you're interested in the rationale behind this.
>
> https://software.intel.com/sites/default/files/m/a/1/e/dsohowto.pdf

Wah. Great!
Thanks for your information! :)

Yu
> Wei.
>

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