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Thread-Topic: [PATCH V2 3/6] x86/Hyper-V: Trigger crash enlightenment only once during system crash. Thread-Index: AQHWARRUpT76HZv44kGCHGoJXYag3KhWai3A Date: Mon, 23 Mar 2020 17:15:31 +0000 Message-ID: References: <20200323130924.2968-1-Tianyu.Lan@microsoft.com> <20200323130924.2968-4-Tianyu.Lan@microsoft.com> In-Reply-To: <20200323130924.2968-4-Tianyu.Lan@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Enabled=True; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SiteId=72f988bf-86f1-41af-91ab-2d7cd011db47; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Owner=mikelley@ntdev.microsoft.com; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SetDate=2020-03-23T17:15:29.9336244Z; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Name=General; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Application=Microsoft Azure Information Protection; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_ActionId=87bb2f05-4794-4cf0-b3b3-6d08018f222a; MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Extended_MSFT_Method=Automatic authentication-results: spf=none (sender IP is ) smtp.mailfrom=mikelley@microsoft.com; x-originating-ip: [24.22.167.197] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: 1ff67fea-6a59-437e-3b56-08d7cf4dcafb x-ms-traffictypediagnostic: MW2PR2101MB1051:|MW2PR2101MB1051:|MW2PR2101MB1051: x-ms-exchange-transport-forked: True x-ld-processed: 72f988bf-86f1-41af-91ab-2d7cd011db47,ExtAddr x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:213; x-forefront-prvs: 0351D213B3 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(4636009)(396003)(136003)(366004)(39860400002)(376002)(346002)(199004)(54906003)(110136005)(66946007)(81166006)(6506007)(81156014)(71200400001)(316002)(33656002)(8676002)(4326008)(8990500004)(9686003)(55016002)(66476007)(66556008)(64756008)(66446008)(86362001)(76116006)(10290500003)(7696005)(5660300002)(8936002)(26005)(2906002)(186003)(52536014)(478600001)(921003)(1121003);DIR:OUT;SFP:1102;SCL:1;SRVR:MW2PR2101MB1051;H:MW2PR2101MB1052.namprd21.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1; received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-ms-exchange-antispam-messagedata: h/2XRq+aFisFzlMSjgYblaOGJR8AQkfRJbjvYiMT3ATfxjUxpEGNDiRO14ZWneC+bjVu+RFhu0+vf8LcsdViLjGpFUywu5LNowmkFVIbsrd6pX1fSHQm2xZuJLEVQ/qPfSS2ATOFcoPYGBk3AoXnhA== Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1ff67fea-6a59-437e-3b56-08d7cf4dcafb X-MS-Exchange-CrossTenant-originalarrivaltime: 23 Mar 2020 17:15:31.9049 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: eBZUBJIAdlF4cpPWpjw9hz4t+dj4QcQzvGO3CfhgZZb12/lIstaHK4toeY6Ff40fPFIvTWAHSwAb+I9f0N44HENFXEzc4Nn96DjqqvaKwBs= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW2PR2101MB1051 Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org From: Tianyu Lan Sent: Monday, March 23, 2020 6:= 09 AM >=20 > When a guest VM panics, Hyper-V should be notified only once via the > crash synthetic MSRs. Current Linux code might write these crash MSRs > twice during a system panic: > 1) hyperv_panic/die_event() calling hyperv_report_panic() > 2) hv_kmsg_dump() calling hyperv_report_panic_msg() >=20 > Fix this by not calling hyperv_report_panic() if a kmsg dump has been > successfully registered. The notification will happen later via > hyperv_report_panic_msg(). >=20 > Signed-off-by: Tianyu Lan > --- > Change since v1: > - Update commit log > --- > drivers/hv/vmbus_drv.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) >=20 > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c > index 3a0472c8b7ae..d73fa8aa00a3 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -55,7 +55,12 @@ static int hyperv_panic_event(struct notifier_block *n= b, unsigned > long val, >=20 > vmbus_initiate_unload(true); >=20 > - if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { > + /* > + * Crash notify only can be triggered once. If crash notify > + * message is available, just report kmsg to crash buffer. > + */ Just to clarify the above comment, let me suggest: /* * Hyper-V should be notified only once about a panic. If we will be * doing hyperv_report_panic_msg() later with kmsg data, don't do * the notification here. */ > + if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE > + && !hv_panic_page) { > regs =3D current_pt_regs(); > hyperv_report_panic(regs, val); > } > @@ -68,7 +73,12 @@ static int hyperv_die_event(struct notifier_block *nb,= unsigned long > val, > struct die_args *die =3D (struct die_args *)args; > struct pt_regs *regs =3D die->regs; >=20 > - hyperv_report_panic(regs, val); > + /* > + * Crash notify only can be triggered once. If crash notify > + * message is available, just report kmsg to crash buffer. > + */ Same suggested clarification to the comment applies here. > + if (!hv_panic_page) > + hyperv_report_panic(regs, val); > return NOTIFY_DONE; > } >=20 > -- > 2.14.5