Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 25 Feb 2021 18:18:12 +0000
From:   Ashish Kalra <ashish.kalra@amd.com>
To:     James Bottomley <James.Bottomley@HansenPartnership.com>
Cc:     natet@google.com, brijesh.singh@amd.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, pbonzini@redhat.com,
        rientjes@google.com, seanjc@google.com, srutherford@google.com,
        thomas.lendacky@amd.com, x86@kernel.org,
        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        DOV MURIK <Dov.Murik1@il.ibm.com>
Subject: Re: [RFC] KVM: x86: Support KVM VMs sharing SEV context
Message-ID: <20210225181812.GA5046@ashkalra_ubuntu_server>
References: <20210224085915.28751-1-natet@google.com>
 <7cb132ce522728f7689618832a65e31e37788201.camel@HansenPartnership.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <7cb132ce522728f7689618832a65e31e37788201.camel@HansenPartnership.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
Received: from ashkalra_ubuntu_server (165.204.77.1) by SA9PR13CA0087.namprd13.prod.outlook.com (2603:10b6:806:23::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3890.12 via Frontend Transport; Thu, 25 Feb 2021 18:18:18 +0000
X-MS-PublicTrafficType: Email
X-MS-Office365-Filtering-HT: Tenant
X-MS-Office365-Filtering-Correlation-Id: d4632d10-529e-4b34-78f7-08d8d9b9b9ef
X-MS-TrafficTypeDiagnostic: SN6PR12MB2685:
X-MS-Exchange-Transport-Forked: True
X-Microsoft-Antispam-PRVS: <SN6PR12MB2685D4DFC42AFC31168559CE8E9E9@SN6PR12MB2685.namprd12.prod.outlook.com>
X-MS-Oob-TLC-OOBClassifiers: OLM:8882;
X-MS-Exchange-SenderADCheck: 1
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: 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
X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN6PR12MB2767.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(39860400002)(136003)(376002)(346002)(396003)(366004)(478600001)(33716001)(7416002)(66476007)(66556008)(54906003)(9686003)(33656002)(55016002)(6496006)(316002)(66946007)(44832011)(4744005)(6666004)(5660300002)(8676002)(16526019)(186003)(86362001)(2906002)(4326008)(52116002)(6916009)(956004)(1076003)(8936002)(26005);DIR:OUT;SFP:1101;
X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?kZ7xk2Lmd/+JcR2b141okrYC3U9rq7lElAVjWUjAeuN0OiCLhlor/tWe8uHm?=
 =?us-ascii?Q?p96ztWstPxBoXRD5f9l7Vk0yxb23q8jPiHZh/h3hP2pyCjPD+eqB77IPZVDx?=
 =?us-ascii?Q?GldzJf80HQQU8VeVFI7EQiUQArTk3lGjGfV5AunyjIHSicYhYg1ESXoYEiI2?=
 =?us-ascii?Q?KDc8ufptn9CEynbZ6XF4WICf2fC5wQx3K4snRweN4Z1Hv+gRAxgEXB0zetlY?=
 =?us-ascii?Q?O6xmZIvw97ZmKlyDvoMO5LechRixE6TA6jq4x9PP0nmG1+8spCo8/l/2usVd?=
 =?us-ascii?Q?ttfktrTUnVOOKJ0ZObzU38WWcCv2vbtL59v941MUCn0AfESUgW7ttjknPZ23?=
 =?us-ascii?Q?FV4itzd1QRalTVp/eegJ1xmfEddsMVkCYEVw+0HAfqc5YT6reBgCep3bS0qs?=
 =?us-ascii?Q?lrii2OIaPiiz3xfCIq0c1DmCB0UJKVXMzIcusVHoIpuJRp3IeLqcJKsLU1ol?=
 =?us-ascii?Q?2xo0lOT6x/yKWFzga8aelFE+YKmykE2vMTS7untCxRsblSwFistJ7Mcgvf+X?=
 =?us-ascii?Q?Njh33MBwmbae3V/NSuWVD48CP83mtgIyV3KHZL4BfdHNe+ywpdztzhx1LLxo?=
 =?us-ascii?Q?3gnaW0dYqBygZNQFG/XxXLGh2PlxE4RPAT52eB37yWQC6XmRCXaqil8BzhV1?=
 =?us-ascii?Q?ZKaOl0HOXQ3ZbQdaIsTR0U5mZIha3vDrGEzt3WYKX4UJdNNHJBtlJ+t919jT?=
 =?us-ascii?Q?PW38f7iMnbimBQZwIm5u4yoArRkGJ+llsrEYOLO+pdIGAcEMGkKEPVOd7Nyc?=
 =?us-ascii?Q?4VSB6BSJ20ZKwbTHGRn6WMZva71ifUSbBKjgrpYXGDTnGTAoWd9HKuWtJx2p?=
 =?us-ascii?Q?JtoFpG/GRxDQYg0aSiQwrG7ABIn7U/RWNFFE/pvumHOEwZziUyY20iaObFbh?=
 =?us-ascii?Q?Z98td8/96naAR6+k0iJqK//aGCh8V5G0qQ/7z3ytOH35mkn9VCSrr1/3fOmn?=
 =?us-ascii?Q?qmBf2x5Pp5nppQ7nLrEP4rudZ03XmY7E7PEj2bn3ozvmmvLIdgW2XQZcpbK/?=
 =?us-ascii?Q?uUkU1o06yw7JIp/r5aPDjijILv8NpDPHCo+rAbET8YL4HnI870202peAIZB0?=
 =?us-ascii?Q?mNjHWZPAwmXff4tF4sLv7AQE0/h55tQAEJJLRaSNrxMneJ7AH7LcBKn4Me3/?=
 =?us-ascii?Q?FmAJ8nQJZMuTftomrjS4TGJe2oTt5fiM5jAWTKftidfSvGPNWNdZ7Fcyry6E?=
 =?us-ascii?Q?Z+0bgG8tbv2L+yctMR0fovofUvmMcVdh+lCpvsuAj/n9/IebGJ268ur5ulrz?=
 =?us-ascii?Q?5bf1G3Et3r7VgLT4VI5TVhSq0xqst3uj3B7JKk2Q590cB8EkHQhVpYsdYiWh?=
 =?us-ascii?Q?dP8u3zwWpGEZkAd1q1u3+oDW?=
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-Network-Message-Id: d4632d10-529e-4b34-78f7-08d8d9b9b9ef
X-MS-Exchange-CrossTenant-AuthSource: SN6PR12MB2767.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Feb 2021 18:18:18.5990
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: QrGWbUWgjy2xuPK8b4tODZnvM2df1J0ZlDuMDVvtq4FZVx/h4t3wZhoUychd+jKbc/vYbQAdh+alXvH/Ta9rOw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN6PR12MB2685
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

>> > For additional context, we need a Migration Helper because SEV PSP
>> > migration is far too slow for our live migration on its own. Using an
>> > in-guest migrator lets us speed this up significantly.
>> 
>> We have the same problem here at IBM, hence the RFC referred to above.
>> 

I do believe that some of these alternative SEV live migration support
or Migration helper (MH) solutions will still use SEV PSP migration for 
migrating the MH itself, therefore the SEV live migration patches
(currently v10 posted upstream) still make sense and will be used.

Thanks,
Ashish