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;
Date:   Mon, 7 Aug 2023 09:16:18 +0800
From:   Chao Gao <chao.gao@intel.com>
To:     "Yang, Weijiang" <weijiang.yang@intel.com>
CC:     <seanjc@google.com>, <pbonzini@redhat.com>, <peterz@infradead.org>,
        <john.allen@amd.com>, <kvm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <rick.p.edgecombe@intel.com>,
        <binbin.wu@linux.intel.com>
Subject: Re: [PATCH v5 13/19] KVM:VMX: Set up interception for CET MSRs
Message-ID: <ZNBF4t+x5Gf14PV7@chao-email>
References: <20230803042732.88515-1-weijiang.yang@intel.com>
 <20230803042732.88515-14-weijiang.yang@intel.com>
 <ZMyz2S8A4HqhPIfy@chao-email>
 <f894d23a-5c6a-d189-57ee-8f2bae0baf6b@intel.com>
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <f894d23a-5c6a-d189-57ee-8f2bae0baf6b@intel.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?S9z8Xz2KS/8/13YcZh5n15JTtk2TIna0Md9N6fGTxU2jPFcN1Z+vPswI5QbC?=
 =?us-ascii?Q?R59CtTKqmn2J6SxHFjh4gPfD0ibMDolqy7n80FvdDg77l60+gpEiXwUDE/hk?=
 =?us-ascii?Q?zsxQ0IGsWS/3XbSCDgNfDC1eJIDHkHTHO3sawaWl7oaVs5XyWBGJuoj9xMjB?=
 =?us-ascii?Q?ySvVc/uvt9f54bISx9xhseD9/v1BToUUgsGPgFC3Pl5M+k2swq1XseVetlJU?=
 =?us-ascii?Q?wurukcP/enbeT7wElA/nwM7a8RTZQwc8v7Z7Rj9MpNW7RGp7boXe6CaZ7cXH?=
 =?us-ascii?Q?HhIb/IDMC7Raga4NprRZ0PAk5doc3tKaj+kPsGZFSGLaN2boqm0P1WU02sJV?=
 =?us-ascii?Q?tVANtyNOdDE/wVVQnHyV/GwWErsVaB/B7WZyip00oJ0bmoeIUFg2l4iu0Y2F?=
 =?us-ascii?Q?z9Uvkefwt+d3eaCRP79CLHYPoOH6Ty7GgPHI4APjuoFdoB+zWDKEzl4z1hP8?=
 =?us-ascii?Q?jGQujBB0WfuLDpCK1DILaVcQsuTF7OjkLpHotoEt3EOItj6j6VbPW/hwMHnN?=
 =?us-ascii?Q?p142T+bo7AbHcVqXZQwgpyDU+gNBSkMVSiOzp6n7T8FxMXYdN8+6pgvV3TE9?=
 =?us-ascii?Q?YSpHyYYkDSJXS1we9qhr4+h/DCGlpJFRdZMfFbC1HdIjA5DrcM0nHKGj5iHt?=
 =?us-ascii?Q?V1vTwPqZ98lWrj4GDNaz7KL8U/Miusj98hvBjwxr5m0riXAjqCchs8PomDGo?=
 =?us-ascii?Q?ftOoCdttE4CCmbqT0+KoThExdTIeBT+h8VyZvHm8gsC/a5wHVQgfLZhvELWz?=
 =?us-ascii?Q?Ep2jiX96brYljAETtvcz7TedtIYIVFCLvUZfFvu5lrczjLo0TE0zZAg/uRIz?=
 =?us-ascii?Q?ZanWL3GRz2t4vPk7CEbrY31HVJUgrBp7Tle6ecQaUH+CEskfQUgSq3rTC3kM?=
 =?us-ascii?Q?YWASH81tmORiMEuXVbqffY+/qdnecw1/jTtw8fC9bjmd0wTuP//SPqFVuj95?=
 =?us-ascii?Q?8SQZKglp92qgAfLVmWA/RRruebeerGiZY9kZjLaQUydiah0TjayBw4Ko6nac?=
 =?us-ascii?Q?Zbd5cCaEJrHgC/IfOVqTdxtXiLR9xKgSERAU39fEsDpG7N8x7trJ3wgY+MdX?=
 =?us-ascii?Q?XmUnMWGNS507Se5ZU2Z3XjuxyNaylZa6xdHHSUPzNqP8yXTOYPvCQ701+F5x?=
 =?us-ascii?Q?LYQ0Ufqw+AEcKEuLl5oCGqrLMPsqcNrJpxX/o5czigAM43x5pRoKN4gBv8Tp?=
 =?us-ascii?Q?h0m1xdDQxsWdgiXhSNbNWv8ehS715O8LPBi9iBWbz364MtCBQbDW+4Y2Szrv?=
 =?us-ascii?Q?NXpaiDB6NUaz7seFA8fl7AGK+uePBuDKX7sia/aFmsvK+03HgjgrO7KV2Vjz?=
 =?us-ascii?Q?8v+4WHrWGerpkkCtIWGpzPgSoZl3W8OuxIZZeU1fIePIqLhYLB0MEE/xQ5nF?=
 =?us-ascii?Q?kQAW27g2RxMw9T33tKIjO0x4VZ2gUFo9On2Rsn+IJTnArObuHyNgCYk0dViA?=
 =?us-ascii?Q?njczmWBXqh/DkuB3gz6SblKcQ1fqpVejRozAQA67qqHY89/s1zxTzHOgZj0+?=
 =?us-ascii?Q?JE4ceDae2CGJ2USARFVKXAOA0qWMctMrzpoKTgla8Alp6YEVl6A6rpdg072q?=
 =?us-ascii?Q?fkySP1mpSJZ/jpPp+bRapCcHAsTUWsYiPc1OtYUf?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 184f7038-c81d-45bf-dcb1-08db96e3ede6
X-MS-Exchange-CrossTenant-AuthSource: PH8PR11MB6780.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Aug 2023 01:16:29.7574
 (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: E4kIrxAXGxAR1q72m012/2awlP1Ff+sEBXHaYzzGIqrb+3GduLwTBsqi2Pf4siPeBqQgKV/COzYlEHgMgcQ6NQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR11MB5247
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,
        RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE 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

>> > +	if (kvm_cpu_cap_has(X86_FEATURE_IBT)) {
>> > +		incpt = !guest_can_use(vcpu, X86_FEATURE_IBT);
>> can you use guest_can_use() or guest_cpuid_has() consistently?
>Hmm, the inspiration actually came from Sean:
>Re: [RFC PATCH v2 3/6] KVM: x86: SVM: Pass through shadow stack MSRs - Sean Christopherson (kernel.org) <https://lore.kernel.org/all/ZMk14YiPw9l7ZTXP@google.com/>
>it would make the code more reasonable on non-CET platforms.

then, can you switch to use guest_cpuid_has() for IBT here as you do a few
lines above for the SHSTK? that's why I said "consistently".