From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM12-DM6-obe.outbound.protection.outlook.com (mail-dm6nam12on2042.outbound.protection.outlook.com [40.107.243.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EBF6626AFC; Thu, 10 Oct 2024 16:33:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.243.42 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728578013; cv=fail; b=JPvzSujeLyJnunAio/i6xACw1ovYnlTvJXrZTegRAkMePjj3NS46Vt/JeeF/I1RsZeSUoITrj0MUiInvar5sWXrSPlakRY60612XkikeUrHOxWtyGZNiGrj3jBYFKkmmULtGXSqIz+IwQyTGtJiWR+q5CQQGA2kbHk1y+AJxouw= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728578013; c=relaxed/simple; bh=ECvQd4p8VLwKKVtdMK/lP22dtNAFKHSbBOO87/r3vKE=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=oXazrcJoAVzXNiZEfeJ69ZYk+vZuvveSGJiBp/bMpAaJQmtFoaVsknErCrKJOSC4DT9rOeM3Mw8eAxs65DudJYqGTDHBBMnw2s7VDw1+GUDuZsg5qFmpYZVGQr4sU6KhQGs2nnjHZTLDuk9lQR6wbxJBPeve8L6GTwfYdMcSMBs= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=Vr/EP6i1; arc=fail smtp.client-ip=40.107.243.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="Vr/EP6i1" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=wnn2PUaMg114aRWVr1QlRDAli6apDWJmXmaq4mUDqI4tWhOGohnGQmhw5sTEnjliHd2Fx1PT+hMt1D4ZdqK11+Ys3LwDv4eBL1IpIP07MJmjBhxGz5IUtFWPKirW5BPRxWAh/2TojBj/3IUhIcRDbvQM5BgL/xmJ12UYAEdPKKyNj8C83yqSyOylGTOuK76wimSKbz8KvFmxKmRY1ZddReJB2570Khip2kEOEF4bQsnzJZhUHuXutFaIGQ+ZefBr5dF796Fv126XvlHsq2Nl3gec4N0BsMezuZhJS7VR5DqZc8siQA6v3Plekx7XdtFA1je1H2825aGB9HBEt2Yqbw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=lFnRw9Vwk+nNZzvIpQ+7i3xLLXoAqOaAm0Ut+7iLlTY=; b=fLQ+AWhuqHBnYoUGa8/X2M9/iJmwwIbN0rTb9F4uDVMJMgU1xUBUa1k5LnFEje8wrtkErftH3pQFzd7unAgeUBfKm8gFToIZzj5guiwP6dyK/zybmjvBnM5omf6IUXae0WiQANaQXcAp3iS+kIzZE3Bm5YFMgrYQ2pCshl9CGGYoztMdO08CJ1h+h69I1XuiYk6hrZXEMyFpDsG1DmWWzaHHQ8m5cTaltBJ5gJnn44KpKDieBDh6mAejRRKAKVmCRdA8sH05EH0E13Ks8TOl4O0ctBGHyKe1GLYzBV9CZekM23hMtFtEAP4xudmyXMYMkBz3kYEh/zApP2/FGfL8qQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=lFnRw9Vwk+nNZzvIpQ+7i3xLLXoAqOaAm0Ut+7iLlTY=; b=Vr/EP6i1b/IStS05UaZF6xBE/qWbSbImYSWrxTdLcZRU9eM68vhGOObrxGZ+4KjRO88m2/91aT0YcKARaVAZ07K32YNCyUj8sWfSW8lTDkCfgijmfctTI4Pq24orvER7KisAHtJ9vmSmWLfJW1eufv0VVw/zVKFjkgjJuyhDcPw= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from IA1PR12MB8189.namprd12.prod.outlook.com (2603:10b6:208:3f0::13) by SN7PR12MB8792.namprd12.prod.outlook.com (2603:10b6:806:341::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8048.16; Thu, 10 Oct 2024 16:33:29 +0000 Received: from IA1PR12MB8189.namprd12.prod.outlook.com ([fe80::193b:bbfd:9894:dc48]) by IA1PR12MB8189.namprd12.prod.outlook.com ([fe80::193b:bbfd:9894:dc48%6]) with mapi id 15.20.8048.017; Thu, 10 Oct 2024 16:33:29 +0000 Message-ID: Date: Thu, 10 Oct 2024 18:33:24 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH 1/6] KVM: Explicitly verify target vCPU is online in kvm_get_vcpu() Content-Language: en-US To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Michal Luczaj , Alexander Potapenko , Marc Zyngier , Oliver Upton References: <20241009150455.1057573-1-seanjc@google.com> <20241009150455.1057573-2-seanjc@google.com> From: "Gupta, Pankaj" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: FR0P281CA0017.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:15::22) To IA1PR12MB8189.namprd12.prod.outlook.com (2603:10b6:208:3f0::13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA1PR12MB8189:EE_|SN7PR12MB8792:EE_ X-MS-Office365-Filtering-Correlation-Id: 239b707c-7fcc-48fc-7f59-08dce9494591 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?a3VMeVBYV2JIVmlXb3pYUDZNai9BRkxERXFyYy9hSWZTUWpyeWo2Q2ZLdU5T?= =?utf-8?B?TVVyWEV5Zjg3V1JvSzJSVnpQNmJrWGh5bEp6SzVEbXlYSjU3MzNCam42SVd0?= =?utf-8?B?dmhwNE9Xdm10THo4VmdaZGFNVElySnhsQVIyTXhmQ29iRDhXcTJKL1RmcUVt?= =?utf-8?B?NzgrSGFtYmdKeFdZbEhpb21rTHdISkg0T2ZHRnR2VXUxRWJtMExPUGFlNTFr?= =?utf-8?B?VEw3KzVUQ1RNcnhmTUJSQitSTE9UeGlvWEN3SDJBSytWSGFrWnNQbk0ySG5J?= =?utf-8?B?TEVXM1hFeHJYUjBnekZYUG54bEliNFlENGQ0S2k2NzM4SXBwdUJic3BXK3lR?= =?utf-8?B?eUJnbEI0aE9rV08wM1NlU05pOTdodHhYZ0dHVEZsOSs5QVdqSkJ3UDdLM2lw?= =?utf-8?B?UDZXRThNU09ndlYzeW4xRW9jOFlXRDNQZjUwR041UHRmSXpnOXJ4MFRqUlNt?= =?utf-8?B?SExhNVU2bHFoRjd2MG5iSWZZUUZuS3EzQWtLdGQ0OThyY1AyanhaeUU4ZFho?= =?utf-8?B?N21JdWlzNjhnZS9Ha0lZdWE3elE4UmZ6LzgrbUJyZCtoSEFQSGl2QkxiOFhR?= =?utf-8?B?L1YrZkRqdjlLRGgvTDBVSTlvRElqZEtlSGNtNUJYelkxV3IwOERyQWI1QWpj?= =?utf-8?B?c3NuSFl6K2VzV3lBTDQwUTZjOG9haEZpVlVodHJLUmpTZUxQVWhWU2FsNUxv?= =?utf-8?B?MFpIb2ZzOWFTYWc3NnlXZVd3VHdMZXRlcWF5S3BUeUhyd3JxdVVnakx2ZTZ4?= =?utf-8?B?UDkzQmo4cnUzd01iYXdGNEg5Vk45azgzM2JRQ2k5T0l4TlFlaWFJcVVSa2M5?= =?utf-8?B?aHZVdUNwVFNPNzIyY2hCSkpWaTdZaGtlakQwVFJQU3VadVcvdnN6K25ZOVZi?= =?utf-8?B?UG5QR1Y1bFh2aFVXSE1rV3BvUXR3eVlSbnFLMFJJVkRPNTJGbUJObm5rNHoy?= =?utf-8?B?Nng3VGR0WHprTFhVZ1N6UGJOeGhrNTBINzBXZmUzc0NiVVVJcWxBS0p6TlpG?= =?utf-8?B?dENUbnZFYlBtM3R3UThucUZ4Mk1yK0owYmhpV1RMOWFFN3ZXdktLZGc5bi80?= =?utf-8?B?bTZGRmd0TlNlOWdiUStVb01kOHphSkE4NVh6Y0V5RzhMYmZtRzl2YnNWanhk?= =?utf-8?B?N1kxT05UMzFtQzVUVzBiQVVUYzQ3OUJ4aERIQldwcDN2ZG9VMlJsNWNkbHdk?= =?utf-8?B?aHJpRGc5MFNOR2FROG5oam1zR1lDcjY2NTRla283eU5qZ0JURjVYWTl2SXZw?= =?utf-8?B?US9TN0xCTnBxNk53bTFyVGptdnpwWXpzc0VOSFB4T2srZTNQK1YwRFEzaFJ6?= =?utf-8?B?dGFFWWpyZ0VJbEVWZnE4VlZNdzloSUZsam1aTjJ5MXlEL0F5Q1BkT1Bmb0JQ?= =?utf-8?B?TnU5YlUycXhvUzRTWGNTcnNpN25kSWp6eXR5Vkl0RWxITzAvSS9DMEY0ck42?= =?utf-8?B?ajJrM25nOVhGTUVTYVg1TTRPYStEWUhrTDFoOUhrK3ExbWtVRUF6ZGdFTEZ3?= =?utf-8?B?QVNnTTJJbk5zbGw2aFR3MWk0bTl5T3B1Tm5KazRkMHJtRVZOWWp6dEE1aTQx?= =?utf-8?B?TXVEcUlpZ0JwY1ZRU2VSZWhBckoyZnV0cm9CaG43QzF3MWhHZW1NT2R4bW12?= =?utf-8?B?S3ExNnVrd052NEV3UzdrcEx6YjFVaEN5WXRIS25uYkZNRCtWT0RQVkNFSGZp?= =?utf-8?B?SFlSeG9kL0lDQjZqWEt3U0x1cXJZc2c3ZXZUNzVJL0lCdWdYK0UxTkFBPT0=?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:IA1PR12MB8189.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UzUwRCt3QmFmUXA0OHd3allPNVhXaFBvV0V5bEVSbHRIQldRSlYwblBBcXNj?= =?utf-8?B?ZnlBS3pxZzIyRWpiSmlUaGJKVUdkUHh3cnpNc3RoUHRCakdkVXBldnp5eEFG?= =?utf-8?B?bDVSYUZKZ1pmOHIrZmZvRWd0c2pHa1Z0UCtOMVRkSTc2WlJic2ZOODZTQ0ZG?= =?utf-8?B?SG5QZGZ3dTVmaFZrOEZ2TVNxaWpycTFBemQ3MTZqV21LdTJnbEZKSG95NkJz?= =?utf-8?B?NDBWUzhoNXFyTVdiV1BscW0rYlcrZEs5NFdNNktWRHREQWUrdXpEUzdnd0ph?= =?utf-8?B?aUxxbUNSd3JIUzFKTUZkdmlQR0JBUk1PbDc5bGx1RUtSM3ZpbFRVNWM2akY0?= =?utf-8?B?OFFENEJOMzF1UkRnSFc0RmVMa0Z3N3FSMXdaWkxteitEK1BGZDY4LzI3c21w?= =?utf-8?B?R2dPcmx5b1FNVTlhZGhOMGZMRCs5SEFPVmhYZXA4WGNJVTVFZFdlVEdoTHJN?= =?utf-8?B?cFhsUVJXeXV0YVBMTDNJVFJ3cXlrS0J1ajAzbjlBSnhpck9qMndxN2VOQzR4?= =?utf-8?B?YlIyMHdNbVVKYjM0akdFZUJFMmZvcHVrZHp5U0srQ0M2eWo2Wlp0d01qS1I1?= =?utf-8?B?alNGVEJBbmoyWldUWXdyZ1U1S3hRTVYyU0owUWp3WmRzOEFpc05MZ1pVRzZU?= =?utf-8?B?dStxalY4WkkzVkw3enArSVZBZnpFRXRzWmhTUjl2bk9TL0M1dndORGxyZ0Fq?= =?utf-8?B?WlVPR2h4TWZUdDZRMGFmc2lVQ3lWMm1RRzZ3WVJwaGRqcHByWm9QTDZNTEVm?= =?utf-8?B?aThwTURNYnFCMHA2MXI5YTBDMEJ5MFF6TGJXY1FpM3VLb2cyZFdndU9sRjFp?= =?utf-8?B?UlN1RzRzUDEzVXBnRGhFdjJ6WllKMVBSekpGeit1ZHlBZkp5emJEMHN1ZHNk?= =?utf-8?B?MVhsMG1lVkZqZC9Ub2FkTXpYdnZFM0lUcndKMnEvN0JORnhUeFppcE13Qm8r?= =?utf-8?B?OU9yWlNqb0tCaEVRT2twS3dKSlNnNkUzWnJ1bGhqcXlTWVY0a3dseExQa1pF?= =?utf-8?B?UmdRTUNCL1FwSmlLcVY3cjRLOUtvUXZpK3YwQ0xCbGhEVFlmeHRiYzBRTGxk?= =?utf-8?B?SnJ5VlQwUWNsS3ZRQkpZZitveGZ5M1M0ZHBFRUpDL29KR2RxNUNWUUFTUC84?= =?utf-8?B?R0JwbjN2eDVxVlVSSlR0V2pQZTg1NkVKZjZMMmR6VkwrQklJaWdqMmFpSmFF?= =?utf-8?B?WlhpN2RNcWZpVEtFeTdadHRRWEtiYnNaam44amZEU0RxOFVqUjVQeWVvc2hn?= =?utf-8?B?QUlmTk9ESWtKVXFONWVic3BRSHorNDRuc3lNT3I5Q2NRd1VqOEQwVjlhdEhP?= =?utf-8?B?UUYrNUtJaWVsYWtIREpJNG0zdDdNdFY2QnZhMWhMMVY3MGE0bDJ4TXJscitW?= =?utf-8?B?UEE2eWRzejNxbUJpRzZsT3lhdGFmTDd2R1RqYVlBNU1nMHNEWmFWd01qUWRT?= =?utf-8?B?bmhVV0ZhZjN0L2hhbkNkb2lHazY3R3dTMEljSDRSMG9PMWxiNHJmY3FNTWhJ?= =?utf-8?B?N1lTYk9MTVhlUWh0TExrcldVMXIvaUt3WkEwd1FRaGZ6M1p4Qy9MTnNGRFN3?= =?utf-8?B?SFkzT2NybnYrSEFka2xBYWJ0NHk3cVVTV0VuZ0pRK0lQWURlQ05zQkRtNEFQ?= =?utf-8?B?cytTMkE5N3J1MDlkaFZVSE4va2JNMzlERCtiNkRHdS9PeDJaWC9aRGE2ZXVT?= =?utf-8?B?dDMyYXFlNnhUMmtWUExOdEZNbEs5VTFtdkhQZXRKQWdGbjBuZm12K2FVMEtY?= =?utf-8?B?ZVBMelFxbnpFR0dTTjRwd0MrZ1hyU2xkdHZLcHUrTEx4aEQvaGRoUnU2azhs?= =?utf-8?B?YTN2cmhCdGdwbVU0M09xNVVCT0lVVXJwRGpSZ1dCU0hUcW56NmRCMU1mYUtt?= =?utf-8?B?ejZRckhoQUw0N2wvQWtoTTdPdHhYVERSeGZiSjNHQkNFdUFXWG56TlMrQkRv?= =?utf-8?B?dkp0VExvL09kR0xxUk1HSjROb01OcFllNm1xK1FQK014WTY2MloybitkQ2FZ?= =?utf-8?B?bjRKQmhxNUorRU8rcXZnNk5oZHpKRHg3UXlHczEzdU0zUGJWdzdzSHBLRWI5?= =?utf-8?B?ZE9IQUJDODlKZnZSdEZmdE1VbmxXVEpPZkYyUDR5THBUMVJCMkR1YWlvdWI2?= =?utf-8?Q?6VYGaoqopRf98qed9KTmsu4Ec?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 239b707c-7fcc-48fc-7f59-08dce9494591 X-MS-Exchange-CrossTenant-AuthSource: IA1PR12MB8189.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Oct 2024 16:33:29.0620 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: MFBkg9tqdxvnfFAmG5OM+hqmM4vwljLAyv//4ND7lnrThypFx9QNxYkADwlAsNX4mPbpkMkrrWFdFdbwmSwBpA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB8792 On 10/10/2024 5:54 PM, Sean Christopherson wrote: > On Thu, Oct 10, 2024, Pankaj Gupta wrote: >> On 10/9/2024 5:04 PM, Sean Christopherson wrote: >>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h >>> index db567d26f7b9..450dd0444a92 100644 >>> --- a/include/linux/kvm_host.h >>> +++ b/include/linux/kvm_host.h >>> @@ -969,6 +969,15 @@ static inline struct kvm_io_bus *kvm_get_bus(struct kvm *kvm, enum kvm_bus idx) >>> static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i) >>> { >>> int num_vcpus = atomic_read(&kvm->online_vcpus); >>> + >>> + /* >>> + * Explicitly verify the target vCPU is online, as the anti-speculation >>> + * logic only limits the CPU's ability to speculate, e.g. given a "bad" >>> + * index, clamping the index to 0 would return vCPU0, not NULL. >>> + */ >>> + if (i >= num_vcpus) >>> + return NULL; >> >> Would sev.c needs a NULL check for? >> >> sev_migrate_from() >> ... >> src_vcpu = kvm_get_vcpu(src_kvm, i); >> src_svm = to_svm(src_vcpu); >> ... > > Nope, sev_check_source_vcpus() verifies the source and destination have the same > number of online vCPUs before calling sev_migrate_from(), and it's all done with > both VMs locked. > > static int sev_check_source_vcpus(struct kvm *dst, struct kvm *src) > { > struct kvm_vcpu *src_vcpu; > unsigned long i; > > if (!sev_es_guest(src)) > return 0; > > if (atomic_read(&src->online_vcpus) != atomic_read(&dst->online_vcpus)) > return -EINVAL; > > kvm_for_each_vcpu(i, src_vcpu, src) { > if (!src_vcpu->arch.guest_state_protected) > return -EINVAL; > } > > return 0; > } Yes, right! Thanks, Pankaj