Received: by 2002:a05:6a10:c7c6:0:0:0:0 with SMTP id h6csp471999pxy; Sat, 31 Jul 2021 13:39:10 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwdHwNY+x2osWP/L136ZowLD2bh772LS1MytP3lwD9MWJzPG9pJwUUx/NmnDqKAw0/NRoBH X-Received: by 2002:a92:7f0f:: with SMTP id a15mr381557ild.245.1627763950697; Sat, 31 Jul 2021 13:39:10 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1627763950; cv=pass; d=google.com; s=arc-20160816; b=S2Z/viHMB6GSF3kHkyZ98b9YjrhI2pmGM7VRt0sDs9+hOS84Jp8fdP2kzkKFwQyDTO QTFRrijYr3/cWE9gazhJS+7duCJFbCsyZak4hYvrl0kOPXFyMgMBllbs/64XBeSua83v bC8oTTP4Lgyyf23Hmdu81LxLP9M5vdgPxt8jzpGkYE0uVMmMQXaezoYBONC5TLfBFrUK vRyezJM7QpOPrPo4xVbrlJLB9gHAnn+SESkYknzPsm5mYiLc7R0K+K+hw8aJjhvj/X7t 59ZKvK/9ZWK46X7XT1HET88MzEPcK90Rz/uDpAt9WjCEVZfbLQ88LyufjUKntK+kJgei BJhg== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:content-transfer-encoding :content-language:accept-language:in-reply-to:references:message-id :date:thread-index:thread-topic:subject:cc:to:from:dkim-signature; bh=7Bg+cN6Pr7mqG2A2iyBK5CfCs8Rz025x3oH4T3aQvSE=; b=vQtqUqPoX3sgY8iK7+LUZnUnBSYUvAk1SE9aRntHfLfxiR70SPUtcA9wX4Em/9iV28 mebn4YKBEgUELvDl/vCOGuFLL1/p3ISEhdgabsXLPiUvs9cxg0yxN2daE5OGBhPyETxj DW9UNASzhn0UtmrDljnk+eTnn9UDavk6Wdt1Oi8lfHUtvDAzuG7hArZBmJeVVtTT+nul GsInMfKWzJSno7+905Of2e7/SSlR86XTDyOdAaU/wngqAsG6gGJEc0HE2jh9v0b+WxOy 6fHfmhFzwE/tDfqNiWvwq95gyc4vKcorYMwqsc0FpcgeuG7g8/qufw/E1mXOa26c4X0z 3iFw== ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@microsoft.com header.s=selector2 header.b=Fxh4mYiB; arc=pass (i=1 spf=pass spfdomain=microsoft.com dkim=pass dkdomain=microsoft.com dmarc=pass fromdomain=microsoft.com); spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=microsoft.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id h28si7417118ioz.12.2021.07.31.13.38.59; Sat, 31 Jul 2021 13:39:10 -0700 (PDT) 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; Authentication-Results: mx.google.com; dkim=pass header.i=@microsoft.com header.s=selector2 header.b=Fxh4mYiB; arc=pass (i=1 spf=pass spfdomain=microsoft.com dkim=pass dkdomain=microsoft.com dmarc=pass fromdomain=microsoft.com); spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=microsoft.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231653AbhGaUgu (ORCPT + 99 others); Sat, 31 Jul 2021 16:36:50 -0400 Received: from mail-bn8nam12on2112.outbound.protection.outlook.com ([40.107.237.112]:19200 "EHLO NAM12-BN8-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229560AbhGaUgt (ORCPT ); Sat, 31 Jul 2021 16:36:49 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=UvrKsqHyIL61FVprPJJ95qOShgD17SYNt2j/ZzC2xhh9e2qMUCOXYdjZatjOG4i17XdvMxpEfxqqkooF1WX2pcjNkGVx/fUr/qMp49qeeYAN78EfapUBhnTZRWLW2E4701PSMg61MOzFqemZ8+tmc2eRVujdxdXRtVcCmfZaaZT06/022c2OgXoU6TZH2FkNNjDYp5Yy15PAyLhYAhTKQEgsa5ULOrihLAgrSGzJesqgLWVbSbJ5B3WcCyu0IKMxUIEIW7PHF4sydg2Lf9dARKp3VFebZJmui8gZ8o03jHwDdROjbLUNjCJ+xJpMFPMCSvSisaUnn6N5Wh1XcbYayw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=7Bg+cN6Pr7mqG2A2iyBK5CfCs8Rz025x3oH4T3aQvSE=; b=JexW2PNx4pShoMArNk1oi4XUOA7c/nawMCUcP8EOuDA3nxJsby8tIwELoGzBwOOpUAaRIinhcw8loQ3dhgcY3zjNLmPCmZBMKlMXj8dRZoDiKNPaCYtGewbwyB8atO7yemk1NuW7KqiJpDSdFaJdy3AJLfc962nLP/RjWkCQr1tPh43tr1kF5k8nxVnbCUi72gYdhMHJf7c+0WV2LF+30YLr26nXxZWEqhUaQnyQATHCB2VKuCxmKH/HxFjoEoVXK1nkdxPPBU5uRb384eGBK6bUMwsorVxmUWcc66lAhfpJTWgo7/oDkWXD5B5IivF8mAsJevBk2brKSsSwhFPtcQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=microsoft.com; dmarc=pass action=none header.from=microsoft.com; dkim=pass header.d=microsoft.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=7Bg+cN6Pr7mqG2A2iyBK5CfCs8Rz025x3oH4T3aQvSE=; b=Fxh4mYiBjcngFlsYREjXvT9/Kluyf2gKbOsdfy56p+aNK2KzP1uoO+1Iuo9zjzjfNWEZOub8zl8bT1vU5jC5fjfgLOsn6yXtUHYM2SQPmHeOdJ0Cyh/3KBQUtuPruQ/ECWKjs80f0g7sXOpI6uzwsdVvEMMk00Sd9iM6UKRX0zg= Received: from MW4PR21MB2002.namprd21.prod.outlook.com (2603:10b6:303:68::18) by MWHPR21MB0829.namprd21.prod.outlook.com (2603:10b6:300:76::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4394.11; Sat, 31 Jul 2021 20:36:39 +0000 Received: from MW4PR21MB2002.namprd21.prod.outlook.com ([fe80::601a:d59b:f64e:5433]) by MW4PR21MB2002.namprd21.prod.outlook.com ([fe80::601a:d59b:f64e:5433%7]) with mapi id 15.20.4415.001; Sat, 31 Jul 2021 20:36:39 +0000 From: Sunil Muthuswamy To: Praveen Kumar , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" CC: KY Srinivasan , Haiyang Zhang , Stephen Hemminger , "wei.liu@kernel.org" , Dexuan Cui , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "x86@kernel.org" , "hpa@zytor.com" , "viremana@linux.microsoft.com" , "nunodasneves@linux.microsoft.com" Subject: RE: [PATCH v5] hyperv: root partition faults writing to VP ASSIST MSR PAGE Thread-Topic: [PATCH v5] hyperv: root partition faults writing to VP ASSIST MSR PAGE Thread-Index: AQHXhgRi9VkW0Z/FOUWxjTerh/knP6tdiy6Q Date: Sat, 31 Jul 2021 20:36:39 +0000 Message-ID: References: <20210731120519.17154-1-kumarpraveen@linux.microsoft.com> In-Reply-To: <20210731120519.17154-1-kumarpraveen@linux.microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=microsoft.com; x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: b5d13c90-72d8-46bf-62f5-08d95462e618 x-ms-traffictypediagnostic: MWHPR21MB0829: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:2582; x-ms-exchange-senderadcheck: 1 x-ms-exchange-antispam-relay: 0 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:MW4PR21MB2002.namprd21.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(366004)(54906003)(4326008)(2906002)(52536014)(8936002)(8990500004)(55016002)(76116006)(110136005)(66946007)(107886003)(66476007)(66446008)(9686003)(38100700002)(10290500003)(316002)(86362001)(83380400001)(71200400001)(122000001)(64756008)(66556008)(82960400001)(6506007)(7696005)(5660300002)(38070700005)(33656002)(82950400001)(8676002)(186003)(508600001);DIR:OUT;SFP:1102; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?ShJ4S0xVESVjtZC/y/vyRDq/yKgLjaXZSLiZgGeF6JaIKbHjcmekni++kIE3?= =?us-ascii?Q?b3VVJwLYL9Y9dIVybJuIQCmRr96RijB79vazKMNiQArT48LFTRy8By634y8a?= =?us-ascii?Q?bMKThw/0ku4Cg/4zViaFIwEnDuCqClUsoF1aMLWYYjZhZANYN1lCGbl2PqVs?= =?us-ascii?Q?LjL0l4UN3NLJkrtMiE3stafK0e3DE7zQSdWDzLJY/GMro5Ab+c2MoqhPruQe?= =?us-ascii?Q?LcglBn+p1YG1wn4W3nLS50hTloOSNCDDX4HV4OmaDI9PcGGVX1s/ZFv5dI/9?= =?us-ascii?Q?xyHg/lui1ezAqV50H6xbbI6dot4+vVvNfxC65LUC/J092i8pZUGqfND8C9xx?= =?us-ascii?Q?5mJDNR+IFfrUAxydfBBUxa2N6dX/Dw4409iUvul0LBGnQLK2bBfoomjOTLwf?= =?us-ascii?Q?NmTgNjVSxAJ9AeCcR132t1Njn1J+F2QrbXgT07bRHuFzzxqQT5R+IHfP1HcC?= =?us-ascii?Q?dXO4f9lOslc2jobAoVlj8w01O/CrMjIB6nOu263MY8ZxODIYoarSmrS6yoz9?= =?us-ascii?Q?3gyMqsYGizUsbmrtEYbE5cUfTZDqWbzX60SELjrAG5ZfwY3pTbBXMxh2O6yK?= =?us-ascii?Q?LnX/WljHo6SRUvguSfcxQtU+f75T6A2ppKyJx+HOjkK17v9kiTYsqux/4xQO?= =?us-ascii?Q?SmDaSgTETCFNcn42TEfwUErCDTt5U6s4gSDNjP8Ws7USK5eT+P8r86jCtI/Y?= =?us-ascii?Q?b3S9tVPvvrhwdb0ywvjUgv1uiIFiFT+KUnab82sEJJYnxhoX8vFIOT8qNApk?= =?us-ascii?Q?m7sjuPB81SAQMSH1U/sur5ZU4XKWUMKmAtkzsKGknus7hYQiCQaXHWn0aWvZ?= =?us-ascii?Q?VZDp00eYaY2AMWlleAWX+SDC1ymwIN2T+m2JZTC2Z+dj92TydsxLcuw2oj6x?= =?us-ascii?Q?p3CRFqn/9kmbECwhw3F7YJvWu16AcYbhrlZ9i785rrDba4Fq1XoHerA47aWY?= =?us-ascii?Q?uPZqmPaT1Ek2DmH5mJt+J+zZdh7RH7wIk5c5AWh6UBwLDJlFcP7bhUulGCDP?= =?us-ascii?Q?qWvibZLYKq5ZBZq46/E1xx1PbVxR15EnmELC1pzjxDYXkw/rlcfVVlxZ/rEA?= =?us-ascii?Q?guQbOSPt3518UImV61oOrAVR7B/PawF44cbS5vYOKO7UWf+blLP16gmwT872?= =?us-ascii?Q?bbUdZMHDq+aytmfL5UspYP0TVQySGJ+2W5B+vR8dq/o0cYR7GjB43IIbMnPE?= =?us-ascii?Q?xZDnF9VRLZSBkTN8XCoQ6YSH6GB8uXEdrgS2GvsRUKz4khaprUj0iMtPTm+r?= =?us-ascii?Q?WQhPo9UBMdGQlz+yDU14sfMhTzawSDInWO6NOibv9C0olBNwBojt8nYZysO4?= =?us-ascii?Q?q+YVao1FRsJdXTT8ez9De1z5faw4NvrGSytj0BDiTFI22c0llIyXgcRfpOP/?= =?us-ascii?Q?io4eFXr95w9MQwD1QddO0ZsuMcrH?= Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: MW4PR21MB2002.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: b5d13c90-72d8-46bf-62f5-08d95462e618 X-MS-Exchange-CrossTenant-originalarrivaltime: 31 Jul 2021 20:36:39.1998 (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: RjAEmsouwZe4KaiOYsoa+kanQ5VkSz4JoLp5aSCjJZ8thSO0drwIcS94ULGcLba8BYDf1tMgacGW5FPNVI3GoR1wd9aH8+T285pxkvSycAU= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR21MB0829 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > For Root partition the VP assist pages are pre-determined by the > hypervisor. The Root kernel is not allowed to change them to > different locations. And thus, we are getting below stack as in > current implementation Root is trying to perform write to specific > MSR. >=20 > [ 2.778197] unchecked MSR access error: WRMSR to 0x40000073 (tried to > write 0x0000000145ac5001) at rIP: 0xffffffff810c1084 > (native_write_msr+0x4/0x30) > [ 2.784867] Call Trace: > [ 2.791507] hv_cpu_init+0xf1/0x1c0 > [ 2.798144] ? hyperv_report_panic+0xd0/0xd0 > [ 2.804806] cpuhp_invoke_callback+0x11a/0x440 > [ 2.811465] ? hv_resume+0x90/0x90 > [ 2.818137] cpuhp_issue_call+0x126/0x130 > [ 2.824782] __cpuhp_setup_state_cpuslocked+0x102/0x2b0 > [ 2.831427] ? hyperv_report_panic+0xd0/0xd0 > [ 2.838075] ? hyperv_report_panic+0xd0/0xd0 > [ 2.844723] ? hv_resume+0x90/0x90 > [ 2.851375] __cpuhp_setup_state+0x3d/0x90 > [ 2.858030] hyperv_init+0x14e/0x410 > [ 2.864689] ? enable_IR_x2apic+0x190/0x1a0 > [ 2.871349] apic_intr_mode_init+0x8b/0x100 > [ 2.878017] x86_late_time_init+0x20/0x30 > [ 2.884675] start_kernel+0x459/0x4fb > [ 2.891329] secondary_startup_64_no_verify+0xb0/0xbb >=20 > Since, the hypervisor already provides the VP assist page for root > partition, we need to memremap the memory from hypervisor for root > kernel to use. The mapping is done in hv_cpu_init during bringup and > is unmaped in hv_cpu_die during teardown. >=20 > Signed-off-by: Praveen Kumar > --- > arch/x86/hyperv/hv_init.c | 64 ++++++++++++++++++++---------- > arch/x86/include/asm/hyperv-tlfs.h | 9 +++++ > 2 files changed, 53 insertions(+), 20 deletions(-) >=20 > changelog: > v1: initial patch > v2: commit message changes, removal of HV_MSR_APIC_ACCESS_AVAILABLE > check and addition of null check before reading the VP assist MSR > for root partition > v3: added new data structure to handle VP ASSIST MSR page and done > handling in hv_cpu_init and hv_cpu_die > v4: better code alignment, VP ASSIST handling correction for root > partition in hv_cpu_die and renaming of hv_vp_assist_msr_contents > attribute > v5: disable VP ASSIST page for root partition during hv_cpu_die > --- > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c > index 6f247e7e07eb..a46bd92c532a 100644 > --- a/arch/x86/hyperv/hv_init.c > +++ b/arch/x86/hyperv/hv_init.c > @@ -44,6 +44,7 @@ EXPORT_SYMBOL_GPL(hv_vp_assist_page); >=20 > static int hv_cpu_init(unsigned int cpu) > { > + union hv_vp_assist_msr_contents msr =3D {0}; > struct hv_vp_assist_page **hvp =3D &hv_vp_assist_page[smp_processor_id(= )]; > int ret; >=20 > @@ -54,25 +55,34 @@ static int hv_cpu_init(unsigned int cpu) > if (!hv_vp_assist_page) > return 0; >=20 > - /* > - * The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section > - * 5.2.1 "GPA Overlay Pages"). Here it must be zeroed out to make sure > - * we always write the EOI MSR in hv_apic_eoi_write() *after* the > - * EOI optimization is disabled in hv_cpu_die(), otherwise a CPU may > - * not be stopped in the case of CPU offlining and the VM will hang. > - */ > if (!*hvp) { > - *hvp =3D __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO); > - } > - > - if (*hvp) { > - u64 val; > - > - val =3D vmalloc_to_pfn(*hvp); > - val =3D (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) | > - HV_X64_MSR_VP_ASSIST_PAGE_ENABLE; > - > - wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val); > + if (hv_root_partition) { > + /* > + * For Root partition we get the hypervisor provided VP ASSIST > + * PAGE, instead of allocating a new page. > + */ > + rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); > + *hvp =3D memremap(msr.pfn << > + HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT, > + PAGE_SIZE, MEMREMAP_WB); > + } else { > + /* > + * The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's > + * Section 5.2.1 "GPA Overlay Pages"). Here it must be zeroed > + * out to make sure we always write the EOI MSR in > + * hv_apic_eoi_write() *after* theEOI optimization is disabled > + * in hv_cpu_die(), otherwise a CPU may not be stopped in the > + * case of CPU offlining and the VM will hang. > + */ > + *hvp =3D __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO); > + if (*hvp) > + msr.pfn =3D vmalloc_to_pfn(*hvp); > + } > + WARN_ON(!(*hvp)); > + if (*hvp) { > + msr.enable =3D 1; > + wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); > + } > } >=20 > return 0; > @@ -170,8 +180,22 @@ static int hv_cpu_die(unsigned int cpu) >=20 > hv_common_cpu_die(cpu); >=20 > - if (hv_vp_assist_page && hv_vp_assist_page[cpu]) > - wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0); > + if (hv_vp_assist_page && hv_vp_assist_page[cpu]) { > + union hv_vp_assist_msr_contents msr =3D {0}; > + if (hv_root_partition) { > + /* > + * For Root partition the VP ASSIST page is mapped to > + * hypervisor provided page, and thus, we unmap the > + * page here and nullify it, so that in future we have > + * correct page address mapped in hv_cpu_init. > + */ > + memunmap(hv_vp_assist_page[cpu]); > + hv_vp_assist_page[cpu] =3D NULL; > + rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); > + msr.enable =3D 0; > + } > + wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); > + } >=20 > if (hv_reenlightenment_cb =3D=3D NULL) > return 0; > diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hy= perv-tlfs.h > index f1366ce609e3..2322d6bd5883 100644 > --- a/arch/x86/include/asm/hyperv-tlfs.h > +++ b/arch/x86/include/asm/hyperv-tlfs.h > @@ -288,6 +288,15 @@ union hv_x64_msr_hypercall_contents { > } __packed; > }; >=20 > +union hv_vp_assist_msr_contents { > + u64 as_uint64; > + struct { > + u64 enable:1; > + u64 reserved:11; > + u64 pfn:52; > + } __packed; > +}; > + > struct hv_reenlightenment_control { > __u64 vector:8; > __u64 reserved1:8; > -- > 2.25.1 Reviewed-by: Sunil Muthuswamy