Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
From:   Dongli Zhang <dongli.zhang@oracle.com>
To:     kvm@vger.kernel.org, x86@kernel.org
Cc:     linux-kernel@vger.kernel.org, seanjc@google.com,
        pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com,
        bp@alien8.de, dave.hansen@linux.intel.com
Subject: [PATCH 1/1] KVM: x86: remove always-false condition in kvmclock_sync_fn
Date:   Sun,  1 Oct 2023 14:36:37 -0700
Message-Id: <20231001213637.76686-1-dongli.zhang@oracle.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?jpBFl8gLSCNo/jH9EWLf7PDyZsbv9cQn6Elp54c/kLyxStgPveiWjPbQq7SD?=
 =?us-ascii?Q?TKUmKOUplLUtht72FSYXQ4b/vH6HMbvN2D6JKGoALAil9xaClGp8Um1Pv7DC?=
 =?us-ascii?Q?KmN8AbxS3ey91I50kYeKWa7XyVAwnRtt4hWKlP6sVtxYsS9n/PU8p11Jy6Ha?=
 =?us-ascii?Q?EKOYbRo+NIstjlGYeuCERpIU/cs4qqPhisuP9hP3QKpaRsGCruo3VpbyADCm?=
 =?us-ascii?Q?RDx22WCG5ZNnDwGejid1dLHwRUZm1mDdaBv5iX/JKez8Nr3nZloSvvI5x0/0?=
 =?us-ascii?Q?1NafIKETlCRfFkQJsCIHZO6V8E3YRoi14DSdjsx4ZsFszSOHpeYTJO8ZlRBk?=
 =?us-ascii?Q?YhrqlCJH8+itWPIQtPOzQ9X180nUzV/0IgDbZLYrxJO/yBQx/T87/lnXOKtY?=
 =?us-ascii?Q?hH0+X9mGr+rmhZrXy1HX4pom69hC0wY9igZmTXY9a/NA3oJaVUfmSTMDqjDt?=
 =?us-ascii?Q?Iv0Zr1A0Mp3ZX1evZPRDVY0cWXSK8JQ73BP0XGzEFmv/S8wtENhe5XAbOqDR?=
 =?us-ascii?Q?Zrhzdr1tQN1fW8kF1FFgot/NVAsCSkOfkvkEp/RxipiGOkoGqCvq3Gf9euUs?=
 =?us-ascii?Q?ZJVgbqd0gfYp6acvGLyrq7XZg5xJ3E9A2tI3uDFRpbcqmrIMn7r5EIjg6JN8?=
 =?us-ascii?Q?Cdwwo3sOQWO/X0QMNj4Q72lt5Y6f1rZe/MOyT/MgNn+A3fxZ6uZ4FxwNhOwA?=
 =?us-ascii?Q?7L8SSZ7cZH7ytd31fBKH9scb9nq3o1T4fNrvUD/gyiNB3mOxox29pc3ZSCHo?=
 =?us-ascii?Q?enbX21wSXUr9CJ0enLQHSFFYdb0dXQu+OpawnuOH5ZwAjmunDD6d82Lp3ZWA?=
 =?us-ascii?Q?GCfu95jTARne015+5u3wvOrDNu4FxFvCJmTUUk8YxyBBPaxdFeLuah2cGoEi?=
 =?us-ascii?Q?/LxmuonWPZodFwDwH+awm5XdmdhBgdCTpo0QUyGcHwyfR7dInnKBfh3Jxm0c?=
 =?us-ascii?Q?LlOB+VxcO0TZEemwTY2f67YLvYvpL1mUoEuZBVFdHiKn46jBcgwkTY5V3qSD?=
 =?us-ascii?Q?sEEOwOmEFO8ojMpFcO95Ei26QD01I+4edlG/EbYyhtotNNUiVce/038IqQhG?=
 =?us-ascii?Q?Dw85n982B0nNgv1isuaa9/d405PIO2kHibwbQn2Th45881Fw+5tG+1y08OvF?=
 =?us-ascii?Q?45mzYBBQeGMSLLB1ZEQ8PL74/9cpD4CAdxOeqzWVWxSOpQTGwICewOUY+u8i?=
 =?us-ascii?Q?F8V6pFl0Dm7c8/diNEzHOyh4zIeKnGc+LixLLhipzoH5vuVAStKzzRTfWTns?=
 =?us-ascii?Q?mUqG9YAP/sifP11lLJeG7wQn9jzmnOn6Cq7l52jjvDfiY2z1WsFxN1j2d66S?=
 =?us-ascii?Q?ljeQYWI/hrZ3mHMgG/bL42tpRAxBBa+K9VA1KV812Ozntw21Rua2kIHzXy6z?=
 =?us-ascii?Q?XvZND8xSbUSHUMqKP6sDDXwb9rpKUxGXHIaWPzUy9EREKkL3X5tOCETM3rWi?=
 =?us-ascii?Q?tCvIBNfdK6JbSahxtPACedNZyTcmwpUnck80aJ43TsTqLzhtyUSr1ZacKRbM?=
 =?us-ascii?Q?JoWu2Rr1Jc8OJq25d3ORlMUDEmvl9ukJnlWtIBp4PdG+zCDUrxbVHhEuVt0L?=
 =?us-ascii?Q?nlroQRt/8sg9csd5E4FJ/ffMglOS88arteXVnXuz?=
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: =?us-ascii?Q?DgBhDAevOrSr+6CgS60bUXs421N/CZfeIVLljtb7X8mwAM1XcUhr02DB/h3M?=
 =?us-ascii?Q?DKmgn3GDOQ9gVOC6ffrGZgWzYpbMRqI6kPxP9WZVD7YlgqlZwQjSjvzE7k0G?=
 =?us-ascii?Q?aXQ5rVq1FvIKredsmQNG/HySLyfiDopiDvfXBQ2oK2EKnHuTYIdDMLgDsYdK?=
 =?us-ascii?Q?uMI8rH/B159hx1wg9o1ytk0SEb9nsKgQ6ZnMjZ0o11RUJ2kKBo73KI0cEwkV?=
 =?us-ascii?Q?2mrCfAkeWe0CgZnT2O0XMRY8LEr3szz1y1L7w5dqJiiD59bTQ6ggqnzEF+P4?=
 =?us-ascii?Q?FKj7HB88WKSiwKj2emogWMP/uK6jo4m7ZoD6SERs7NfecWoSoH0653ZS2vZd?=
 =?us-ascii?Q?7Gmz3ib48ss+GYM7VowqRmAMC4ehI6Z7m3owh4w7BYxy1JMb/63D2ek+hW1i?=
 =?us-ascii?Q?qvF3zLFThvjoQJnnLt1mWCbHbgnUGGl2QRotY5JbIvCWn+DiD2Ti8KzLHlQt?=
 =?us-ascii?Q?CjW5tD08IJiXBdKEpGjUK0Te8LpQp1PN7dqdgZNfC5obyNB8o+T7DcOhMxJV?=
 =?us-ascii?Q?NH4+33cnqHMbOn2ZtCS6pcyfyoC7Na+9wEjrH6Pf/8TiTOytEnQSTtMxPHu5?=
 =?us-ascii?Q?fwQBhqaoqlxsW1K8Sfw//v549j7hML2e5P0JTiof3KgtnDobbsF0XgzoZImW?=
 =?us-ascii?Q?6WhlxScV4JLUwO1pSw3v2ViM5Hx1YcFweS7NBI/sV7LM1l7zBeZfBbmVKBz1?=
 =?us-ascii?Q?kpAXlIQdp4Ld9R9gu2ETojOIImD2LO1TzXGdX7z7eoxh23AxUxu7evr925RS?=
 =?us-ascii?Q?1rqOl6PxeuxdsX748UxUOsHMScHh+Esj5rTMHaNutuchEtb+ho213na94dQq?=
 =?us-ascii?Q?RPmLU+1RoORJBP/FIWb3GK0nhcq+fJZRmLXrHhDbErZiiuLurXmqh07+19rj?=
 =?us-ascii?Q?6vtbCizDk8EZpMMTa4HPupBL8NA3aqGoG2LU+RHVMIeFVZZ/Lr5sTLHZb6cp?=
 =?us-ascii?Q?u7pS+fTAIKZ479SgeawocQ=3D=3D?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 30c633ce-1145-4d14-66e6-08dbc2c6f3f6
X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB2663.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Oct 2023 21:39:55.7958
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: FYOiOTKlcpEIvVzDG+LjuBkSmhtmXGWrkwGGsm1vC72f9csyCByu096W8CZxNqDN+yXaYOjM+BV+6OvPEefcNg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR10MB4613
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26
 definitions=2023-10-01_18,2023-09-28_03,2023-05-22_02
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxscore=0 bulkscore=0
 adultscore=0 mlxlogscore=999 phishscore=0 spamscore=0 suspectscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000
 definitions=main-2310010174
X-Proofpoint-GUID: a7yzKAR8WWfZFUx_4J9ZqcsqEUsXzF07
X-Proofpoint-ORIG-GUID: a7yzKAR8WWfZFUx_4J9ZqcsqEUsXzF07
X-Spam-Status: No, score=-3.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,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
X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Sun, 01 Oct 2023 14:59:37 -0700 (PDT)

The 'kvmclock_periodic_sync' is a readonly param that cannot change after
bootup.

The kvm_arch_vcpu_postcreate() is not going to schedule the
kvmclock_sync_work if kvmclock_periodic_sync == false.

As a result, the "if (!kvmclock_periodic_sync)" can never be true if the
kvmclock_sync_work = kvmclock_sync_fn() is scheduled.

Inspired by: https://lore.kernel.org/kvm/a461bf3f-c17e-9c3f-56aa-726225e8391d@oracle.com/
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
 arch/x86/kvm/x86.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9f18b06bbda6..38fd04a286c7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3290,9 +3290,6 @@ static void kvmclock_sync_fn(struct work_struct *work)
 					   kvmclock_sync_work);
 	struct kvm *kvm = container_of(ka, struct kvm, arch);
 
-	if (!kvmclock_periodic_sync)
-		return;
-
 	schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0);
 	schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
 					KVMCLOCK_SYNC_PERIOD);
-- 
2.34.1