Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <920ede72-c2fb-c814-7b1c-aa488e400f83@suse.com>
Date:   Tue, 25 Jul 2023 09:49:51 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.13.0
Subject: Re: [PATCH V3 1/2] xen: Update dm_op.h from Xen public header
Content-Language: en-US
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Vincent Guittot <vincent.guittot@linaro.org>,
        =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>,
        stratos-dev@op-lists.linaro.org,
        Erik Schilling <erik.schilling@linaro.org>,
        Manos Pitsidianakis <manos.pitsidianakis@linaro.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
        Juergen Gross <jgross@suse.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
References: <ffae9d7021829fea19fd93fda3c30b52b0af923e.1690190453.git.viresh.kumar@linaro.org>
 <1498bef6-ded0-1b1f-a5ca-e8755800b489@suse.com>
 <20230725070914.m3dxlokedrgjlgcu@vireshk-i7>
 <3770f13f-0621-48af-4c79-880a0ffaa8a6@suse.com>
 <20230725074218.zcgbkkx5pfgszimu@vireshk-i7>
From:   Jan Beulich <jbeulich@suse.com>
In-Reply-To: <20230725074218.zcgbkkx5pfgszimu@vireshk-i7>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?cXF3Z1hNeEpOYytZSm0wSVM5NlhTRXJTRWR3RXZTQ0xQZ0M0QWRtNERLQTdS?=
 =?utf-8?B?dThJb3h5MkU0bUJCQlJ3c0lraEt2TVVKZm5rRDdFd1RtSTg2M0tMYUsyNkds?=
 =?utf-8?B?ZkRNeEFaSG1WdFhBVkpVN3Vsd1RNemZjUStzV1BnYjA4WFRQbWdLSGtxTlhU?=
 =?utf-8?B?K2JSZGI4cklFdm1HV0RYQ0lSaCs1aG5ySGRTQiszQlBhVGR5Wml6QTBJQmdy?=
 =?utf-8?B?QiszRFE1SE8zRlJhekFTRzdpMmpmUzNJV1JWUFBZT25OZXdMenY2K0ZuVHhk?=
 =?utf-8?B?MXBjOTEyOEVOUlJFUmpRQitNRmVVTTFocEJxSWQ0VU5DRCt3RStLQW1iSlAy?=
 =?utf-8?B?bDhFZ1VEUUZZV0NONS8xeXY0Zkc2VzZWb3FVNWk3NEJBREljV1loUERKelpt?=
 =?utf-8?B?M3JTVGszNDZUTW5aVEl4TGQyZ0p1MWRqTlRuWjNnVWZ4U3VVYVhEVTNPb3FG?=
 =?utf-8?B?ZlpGbVpoZzk0Uys2R3J5S2Y0UENKZXJmazllMmkzVWNwekpGSVVaMFVUc3JV?=
 =?utf-8?B?STRXK3EwQXJzVHMxdDYzNFE4WDRZd3NyaTE2Tmk1a3Zzay9SZ1gvMUQvRUdQ?=
 =?utf-8?B?MThiRytVbjVXeUREYUd0ZldxQUY5Q0U4V01YY2p3d3VVVHhTNG5USGd0aFBu?=
 =?utf-8?B?SXVHTTBiNkxJL1UvRTVlWnYyVUhmSXVqZDh5WWZXd0V5cERweFVjaFpRbUZu?=
 =?utf-8?B?TnYzYUJyMTFWZFRCckt4enhqcFhIMWFMazJnZUM1ZVcyM2NnTXRQSGRsTzhp?=
 =?utf-8?B?SzNSYzI4d3crdzlzekpIK2orNGxXUnRBczBWYlc0UTh0RU1yZ0ZaK0o4cUNK?=
 =?utf-8?B?QWlHQXlJdXdQbVhzUnBFUlNJVW9tQW1xY091b3JtN3I0c1FRVEI4ZkkvU1c3?=
 =?utf-8?B?VW5jc3JrV0VQMTFsRGFpWm40UGNUNndBZ09hZ0NML2VNbWJSOEZadzFLZkhu?=
 =?utf-8?B?UXR1Wm9FSFZMQ2xJb3BGU2lsQTdUeG1xbDY4WE02eUg1QjE2dGFCQW5hd054?=
 =?utf-8?B?MkF4WE8rV1JWdTZKQldYQTJPT3FXempzRFhhemROTDlGeFZwS1ZsRDJocXU0?=
 =?utf-8?B?cTM2MXpLZzRUb2NuMFg2SU9mbExxb2hOcnRsVExjSXdoRXdrZW1FTm50dkE4?=
 =?utf-8?B?ZnV5WHNzcjhXei9keVhYSERWWUxmbWtZZzVxVmtoTnp0TmNSNm5RczJQTEE2?=
 =?utf-8?B?dEJMT09kSmNTU1VxdjBwNEJVUG8zQXErZDFrdzZHS2kvN0pjVFZNc3ZScW1O?=
 =?utf-8?B?WkRPaEVHbGkyR3VnK1VMMzdEa0JmTWZBVGRobnNmOFJkcVQxbEhERkVxSnhN?=
 =?utf-8?B?MVhVMG1LNlgxd2xhTENqVmdqVVd5ZHlFc1Z0RllKK1kwcm5SZWVUeWxNUjhO?=
 =?utf-8?B?TTY4YllOOCtXaW9TTG5rRXJRRmdtYzliTTFhdWhJcGZhS3Z0ZWVSWWFraTRl?=
 =?utf-8?B?N3MvKytJNVRSZ1VoS1ZYK0l6d25lSWpILzltb1dpQnBaeTFCWFFJL0JTbURj?=
 =?utf-8?B?MDlMWDdFamFFUzFSdzhvSlQ3dTZGaFFBMXNkUCtMRkVoWnJPY1R1TG12NWFY?=
 =?utf-8?B?ejE0MDkwZC80eG53RTZVY1c0UjVwZkRXdUVHQ0lqYXoxcWdrR2FFY3N1bStl?=
 =?utf-8?B?VHNOa0tOS3FwNytTMlZCYm1uOGg2S0VoWjBYNmdmSlJYMERpdnRxOFd2d2FQ?=
 =?utf-8?B?ZDZHLzVGLzhwTmNHdjIxOXN3OFF3eDhMSEl6Y0p3N0F0MDdvUmNsaTd4aWFD?=
 =?utf-8?B?d3VWalRUM1lxa21DeG9FbmdObU1nV3JuUTk5QmhOSG9oejR1TnhkQ2N0WjFF?=
 =?utf-8?B?SW9OK3FWWVVFckZUc0JleGRqbmNsbzBDcDAwcFJMSjQ5ME5VNklPOTZZdm9a?=
 =?utf-8?B?Wlk1Syt5NFlUeTVSQXJzZ1ZKVHNkZ1UrMWFzUGd6Y0dVR0ZOWDMyZGVQNEdN?=
 =?utf-8?B?N0gzMGc1bHF3cjdFWnB6cWhQMmM3OUxlMWJIaE56NFp5KzdqVmwxbUJxOVNL?=
 =?utf-8?B?ekZEQ2ZoZDF5TUFqZDRzYS82NmUzUUR4UUd1WkZVMFFwUUZEVWhmWCt2M1Ji?=
 =?utf-8?B?OStDUEFGYm93N08yWkRlTitrZTlrUmQ4SDEwcDYwZ0lFSmlnaDJFZ01tOXFG?=
 =?utf-8?Q?yDASf07IwxwFY9EwKwhHn+Plf?=
X-OriginatorOrg: suse.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 6f9911ab-333b-4380-3d6f-08db8ce3bb94
X-MS-Exchange-CrossTenant-AuthSource: DU2PR04MB8790.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Jul 2023 07:49:53.6848
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 5zxKfk0H1aK9mMTdEApZvO1rQ4495PPR1+i4Ogddnicx4jiNVeld2xOcBhbTO6BWDW1L2iKtl+btb5r9T0P9IQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS5PR04MB9942
X-Spam-Status: No, score=-2.2 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,
        RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,
        URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 25.07.2023 09:42, Viresh Kumar wrote:
> On 25-07-23, 09:18, Jan Beulich wrote:
>> I question that use, btw, but it is not up to me to decide whether to
>> accept such a layering violation in Linux. dm-op is, as its name says,
>> for device models to use. Your intended use doesn't fall in that
>> category, aiui. Imo the present contents of dm_op.h in Linux is indeed
>> all a kernel is supposed to know about, unless it was to gain in-kernel
>> device models.
> 
> Is there any other way by which an interrupt can be raised for the
> guest VM ? I was only aware of this method and so implemented it like
> this.
> 
> I am open to suggestions on this.

Well. I don't know your requirements. Generally I would suggest using
event channels, not interrupts, when talking about injecting events
into guests. If it strictly needs to be an interrupt, then I guess a
non-dm-op means would need introducing if none already exists.

Jan