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: <2e5a167b-2923-e92a-b6ed-db6c2cba0827@intel.com>
Date:   Thu, 27 Apr 2023 23:57:00 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.10.0
Subject: Re: [PATCH v2 09/21] KVM:x86: Load guest FPU state when accessing
 xsaves-managed MSRs
To:     Binbin Wu <binbin.wu@linux.intel.com>
CC:     <seanjc@google.com>, <pbonzini@redhat.com>, <kvm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <peterz@infradead.org>,
        <john.allen@amd.com>, <rick.p.edgecombe@intel.com>
References: <20230421134615.62539-1-weijiang.yang@intel.com>
 <20230421134615.62539-10-weijiang.yang@intel.com>
 <a46895fa-3ffa-e2d8-2841-625a1f791ece@linux.intel.com>
Content-Language: en-US
From:   "Yang, Weijiang" <weijiang.yang@intel.com>
In-Reply-To: <a46895fa-3ffa-e2d8-2841-625a1f791ece@linux.intel.com>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ZFRkWlNPMmQ2NWl6WjdwZDAzemt4bjlReDZZWHd4TXBaZlVNOUlpV2ZMZ1RP?=
 =?utf-8?B?dkxFN0ZGZWhqMHM1U1F0RGVOVmtYK2pjZEI4OEllWGVlTkU0TE5wZnVuMlFW?=
 =?utf-8?B?bGRSM09ENFlMT3pQOUVJbFE5V2M5ZE9TR1cwN3hlSVNvaEFRcHVFVFJnc1lt?=
 =?utf-8?B?Qyt6VzhQNlB5UmQzNTlSbEJhcGZ4VjA0Z0M0bGpIQmtnWmF1aVhyY09mVXFZ?=
 =?utf-8?B?bmxkbWVwTW1admZvekdTdTJxeTc4MHhJczBXVjI1R1VHS3lFYWVYRlZkbHRI?=
 =?utf-8?B?QmJ2ZWxQSVBFNmduS3NCbndrSmM0LzdETXpVZ29UMW43ZWh1aWloZGp1N1Zz?=
 =?utf-8?B?S3k5QU45U3dKS1pHT3JoNnlVZUlYYlc0V08yaElTNDhXMGFtTEtMTm9YbEk0?=
 =?utf-8?B?aGNmRlpEVlJQUit3eGw3ZWtMeUNpcDJjT1QyOGUrekVlL2ZhaEhFbmFFQUlC?=
 =?utf-8?B?RW0xZzlZYmFudnoxV1Z5dEVPMElDM0RkZVZObW02aDV4VkZRWjFCK2s5Zit1?=
 =?utf-8?B?d1I4YWM1UXVaSTR6eFFWK3pCOHRwSlVtcUMzb2s1dFpiK1pIY09HOUxRSVcx?=
 =?utf-8?B?QjNidTNRTGJjdVdBNWlMWVR0SW5BcGU5TTh6WUxCVzdPMXdwcnRzWXJML1hO?=
 =?utf-8?B?K3djV1dad2dBNWZZRldoZWhxWE90aGRaSVdESk0xV2RGSTFzcHh5cnJCOE5W?=
 =?utf-8?B?L056TGx2RE1WYXF5L3UxMkJ4alh1bVlFOHQxQXh2L0pmWVFnOHRRNGliREND?=
 =?utf-8?B?czNkZUNCR2YxWmlsd2RvTG9xWHd4Q0pMeFFkUlhCbE15NXZERWYzU3NicE5t?=
 =?utf-8?B?TTMwUFJCS3dDRDJOQXNERFhjdnlzM3E1SXA4YjFjUFRDKy9ROUl4TzNsOGNW?=
 =?utf-8?B?N0p2V2haWWJvay9jSVh1NEloV3phLzJabVZ1RzNYbS9SVFYyUzBNTDR3cDBW?=
 =?utf-8?B?eWZJS1pmY2EzUWxDazhncGhMZEVTNTAvdWxtcHJkbldwckpoMWZ0SUlFWmVN?=
 =?utf-8?B?dWl0d2ZqSGVXc01zUjhWcmtZMk4zRUwyMGhvYnVUSUFINGVBMGJ0aFVuRTBk?=
 =?utf-8?B?TUNYMHdJdGhOMzVzYjlHWUE5YjZNZjVQdFhhSUNNVWdvTlNtMkJSKzBIYU91?=
 =?utf-8?B?VTljbDZiRld5UFBZTjdSeUl5a3JFV0Uvd0oxK093MWNxekNON3dSZ1ZuazFw?=
 =?utf-8?B?Q25NdHJ2Mlozdjd2d0tORkJ5TVEyNVBZRXdFeXQ4bGJ1eHVJcWdGWWZOZDBY?=
 =?utf-8?B?dEtPdnBrTEQrTG5xODBwajFpZUlyQ1l0cXp6K0ZmVHV6T3dpTDI0VVdBcmJC?=
 =?utf-8?B?STFtaWhURkU2WGZ4dVI1bW5HZlQvSEZHYUtrYmhyc1pJd0FCczNMRU9FOWov?=
 =?utf-8?B?MWtuWDZ5eUhEbFJrcmFiMGMxbFc5ekdpb1ZIUVgvazNxZUxkVWkyVlJRVlNT?=
 =?utf-8?B?SGxIWHVFUmovZ2RTNy9FanE5M0g2b0JIaDd3R2dPU0xFMXo3dkFlbkN6MEpZ?=
 =?utf-8?B?K1BGbDhiYU4vN0gxM2lRVDc1TmtIU2ZITzY4ZEZ0cmFIcWRKdGw1eGhHMDVl?=
 =?utf-8?B?S1Y2VDByUjZrenlFVml5TTZQcjQxbGVIM1lFUUUvbjY2VVRHSXhOVDRTeWFU?=
 =?utf-8?B?d0NQZEVLTEhUREdTd25WSGVwVHZwVDU0MlBKTDJqc3pEa3ZJK3o4cS9jTWNq?=
 =?utf-8?B?T2FUNHRxTzV0SmdkMnU0bDVYZnFNb1RVSVZwU29ZTThHTVBUdjhiMHg4anVi?=
 =?utf-8?B?bng4cFBzNzJRcGNXajM4VVhLS1BBTTdwRTJKTU9TMCtYZlNERXh0TVlPYnJY?=
 =?utf-8?B?Y3dLdnNBZlh1UHNUSG9VNWU0aWIxc2x1YVJwOWthalFZVjhpM2gxNGo1enZ1?=
 =?utf-8?B?M0IyUTBubEpadEt5cmd1RnIrMXlsdDJrcXVpNDNKK1NiRitZWDgxemEzSFpF?=
 =?utf-8?B?ZjR0d0VPOTdiK0NGbzJqbTJsN0ttNVFTY2lCM1pSWWY1S3Q2VE00Z0k3bFYx?=
 =?utf-8?B?c3RnNm15TTZQc3dLVFN3ck1KV2V4RmU3ZHl1UUlTUkVhZVJSME5wb0ZvNWNS?=
 =?utf-8?B?VUtGNXk2QmNWVmZIT0dZU0x2dGZaOXFDNmgzR1dGTXVIUUZWd0YvN0tLOXFI?=
 =?utf-8?B?YmlxTGp2S2toL2xRczRqU05pWTNRM0dGMWh2V3BBakRHV2cvdCtubWNnNU5R?=
 =?utf-8?B?eHc9PQ==?=
X-MS-Exchange-CrossTenant-Network-Message-Id: c549a234-8d67-4fd1-3bd6-08db473811c1
X-MS-Exchange-CrossTenant-AuthSource: PH0PR11MB4965.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Apr 2023 15:57:14.9104
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: rBVlHI43fUOrDIFXkYPtCqUoBG5cD5qC1pUEhNHehezQ15rng5EAVmy5Y5P/pYqbYQwaynQdNCjuTiqwzwYHaA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR11MB5771
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-6.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,
        RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE
        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 4/27/2023 11:46 AM, Binbin Wu wrote:
>
>
> On 4/21/2023 9:46 PM, Yang Weijiang wrote:
>> From: Sean Christopherson <sean.j.christopherson@intel.com>
>>
>> Load the guest's FPU state if userspace is accessing MSRs whose 
>> values are
>> managed by XSAVES so that the MSR helpers, e.g. 
>> kvm_{get,set}_xsave_msr(),
> So far, kvm_{get,set}_xsave_msr() is not introduced yet.
> IMO, it is a bit confusing to understand the whole picture without the 
> following patches.
> May be add some description or adjust the order?

Sure, will add blurbs for the two helpers., thanks!

> [...]