Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 2 Feb 2022 13:03:29 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Cc:     "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
        "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
        "mgurtovoy@nvidia.com" <mgurtovoy@nvidia.com>,
        Linuxarm <linuxarm@huawei.com>,
        liulongfang <liulongfang@huawei.com>,
        "Zengtao (B)" <prime.zeng@hisilicon.com>,
        yuzenghui <yuzenghui@huawei.com>,
        Jonathan Cameron <jonathan.cameron@huawei.com>,
        "Wangzhou (B)" <wangzhou1@hisilicon.com>
Subject: Re: [RFC v2 0/4] vfio/hisilicon: add acc live migration driver
Message-ID: <20220202170329.GV1786498@nvidia.com>
References: <20210702095849.1610-1-shameerali.kolothum.thodi@huawei.com>
 <20220202131448.GA2538420@nvidia.com>
 <a29ae3ea51344e18b9659424772a4b42@huawei.com>
 <20220202153945.GT1786498@nvidia.com>
 <c8a0731c589e49068a78afcc73d66bfa@huawei.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <c8a0731c589e49068a78afcc73d66bfa@huawei.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?P7M0ncOeA70D4lK72BS4NK1NDq0iN0drfN94af/uxa2YOAxm/+Bz5fLQWpg1?=
 =?us-ascii?Q?uKw8KrbCiA4OotQtDE3SMKMb7WTJBMEYJS1c8icneLMu6xVAz7i6utkIi3KR?=
 =?us-ascii?Q?yj7EHfSVMto3AlcS7h+Br6P0Q1BdsgHJemOsv69vkG1j3NYM8t4JWePFK998?=
 =?us-ascii?Q?VpYDyEh9NB28qEUPSsIr3+j7sxj3v5bR5p77vUCek4eHOhl0kJZub6KdCmPh?=
 =?us-ascii?Q?l0bSNY/Gn5Tv2OodDXHH6X05bAun3RVL+sfVKMsDjOv0J5KcIqwT9pNdVaNE?=
 =?us-ascii?Q?oCcunbj7kPU5AQqzTMVjqI9XO0heHiKEZBPN1AVK8nMxAA+3NTVT13kQEEK0?=
 =?us-ascii?Q?rNc3ljJIkIdMJvS6SIdjrllU6ME0wvuvId11oaECQyzDcK/ECM0ZeijIQ3Yz?=
 =?us-ascii?Q?DST/oSROfd7yhQv3+luyxQGBtpfckltrXx/bV9EbZDQGpZKRS9D2DULsP06D?=
 =?us-ascii?Q?pE+LqM9hzFhIzbkPOAAfFteVBZOkPdyDTHPso6LlH7ZHxhqqCTLwr4OCCgBo?=
 =?us-ascii?Q?u9Cq7sbBpkSusU75UhxIcz6Il5alN0uoKaVeoSo9Fswr7Wq9fqTHuF/sAhkd?=
 =?us-ascii?Q?tY6NTfGmpeZIk+V38U5uQAe1HNfB4/KIl/vYqUxytpu2vq4MEo/ND17Ioi63?=
 =?us-ascii?Q?gxpOVmy+Cp5cltSwKVbbkqnaOh/5yeCFUTBTyIpIzrNmBNFWL5WaPrUbpgfr?=
 =?us-ascii?Q?YGVm52YJg2kInxj3/gpd2vX5BChje3l7grBPM7afHdukIAVf6vCvM5YBc8Lh?=
 =?us-ascii?Q?y0sXkCJlgG3uAshs3yrf8GIKz+7ePhSCzdJiP/OVAeriF2MypWDGOA1yQHsH?=
 =?us-ascii?Q?wtRK9CWigROaUdc1ySxi5rjrFLqw5T1RXPY1PPVNM505PPUeCYXOLMSuTYjh?=
 =?us-ascii?Q?4RdKxfUoE/2OHZogULTrmx2mr9qaG/GjsWKto3ZHg/PNNpNRU7ZqMQbx0Osm?=
 =?us-ascii?Q?ZCkdAXcoDczR5TC20xWHTCqkLeNQGB1Y2LpMh043+lwwdQ3dI6o13+JAK4tB?=
 =?us-ascii?Q?EnX9QSvpgx2GN9SGMU2wVaZ8PKYUhcOKUvX7+i1y9TpdqE0dkaofoJ7KN63F?=
 =?us-ascii?Q?xVRCaHaafMsqjq+3I3O/b/LfQRi8lihzd+sysXPe94YR9y0fOaJbNb2XR7YI?=
 =?us-ascii?Q?uhkx26B5xNfmsdq299P5D+Er7Ftrdd6JviRbsssa6PxtCDURC0EqpekGdeFS?=
 =?us-ascii?Q?1NJl6LBEgurVgJkWjaOdJWIuDpE7H1iU953qVGVF9Uh2RHWwAbWrVdAvnBrs?=
 =?us-ascii?Q?5DYx3OHUfOEpZv+6Ffj39GLbVUd5VFor0hLLpufy1taz3cjMBBSY2a6Dsdvy?=
 =?us-ascii?Q?a5CRElBNpGYCu3nd4zFaqMZUwG/x8sWwo9rhA1ighzSz9aZrKlFJ160Qt0X4?=
 =?us-ascii?Q?rso1lx/HXUsiUrJjWBx3OrHXIsFIQyjIJoWLuF/1M+XZ+CkgfXVcOFn7yT7v?=
 =?us-ascii?Q?/6lJxkl2gmNRZOYnEQVnQ+mtt8dLxDKxn58vs1ZRWFECQwE1+SjjeT4ySvDO?=
 =?us-ascii?Q?MVnCW0ymiX2fAyTUW327f8fwu5nBfcTTHWkcxEN0ZQ5g+8l9MFkMRF8XQDXM?=
 =?us-ascii?Q?pwHr+x/IWHz0BooPhYA=3D?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 0e4b07c1-771c-44bf-e5f2-08d9e66df056
X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Feb 2022 17:03:30.8623
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: viesGuCtsMA005hdNLhoSbxV3LaezBdId+bdsonbnW/CLn8if/mi/DeeBlQjD46b
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN6PR12MB1266
Precedence: bulk
List-ID: <linux-crypto.vger.kernel.org>
X-Mailing-List: linux-crypto@vger.kernel.org

On Wed, Feb 02, 2022 at 04:10:06PM +0000, Shameerali Kolothum Thodi wrote:
> 
> 
> > From: Jason Gunthorpe [mailto:jgg@nvidia.com]
> > Sent: 02 February 2022 15:40
> > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> > Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-crypto@vger.kernel.org; alex.williamson@redhat.com;
> > mgurtovoy@nvidia.com; Linuxarm <linuxarm@huawei.com>; liulongfang
> > <liulongfang@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
> > yuzenghui <yuzenghui@huawei.com>; Jonathan Cameron
> > <jonathan.cameron@huawei.com>; Wangzhou (B) <wangzhou1@hisilicon.com>
> > Subject: Re: [RFC v2 0/4] vfio/hisilicon: add acc live migration driver
> > 
> > On Wed, Feb 02, 2022 at 02:34:52PM +0000, Shameerali Kolothum Thodi
> > wrote:
> > 
> > > > There are few topics to consider:
> > > >  - Which of the three feature sets (STOP_COPY, P2P and PRECOPY) make
> > > >    sense for this driver?
> > >
> > > I think it will be STOP_COPY only for now. We might have PRECOPY
> > > feature once we have the SMMUv3 HTTU support in future.
> > 
> > HTTU is the dirty tracking feature? To be clear VFIO migration support for
> > PRECOPY has nothing to do with IOMMU based dirty page tracking.
> 
> Yes, it is based on the IOMMU hardware dirty bit management support.
> A RFC was posted sometime back,
> https://lore.kernel.org/kvm/20210507103608.39440-1-zhukeqian1@huawei.com/

Yes, I saw that. I was hoping to have a discussion on this soon about
how to integrate that with the iommufd work, which I hope will allow
that series, and the other IOMMU drivers that can support this to be
merged..

Jason