From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D08AC433DB for ; Wed, 13 Jan 2021 23:58:55 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C298821734 for ; Wed, 13 Jan 2021 23:58:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C298821734 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.66799.118796 (Exim 4.92) (envelope-from ) id 1kzq1r-0000IW-E8; Wed, 13 Jan 2021 23:58:19 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 66799.118796; Wed, 13 Jan 2021 23:58:19 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kzq1r-0000IP-BB; Wed, 13 Jan 2021 23:58:19 +0000 Received: by outflank-mailman (input) for mailman id 66799; Wed, 13 Jan 2021 23:58:18 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kzq1p-0000IK-Pj for xen-devel@lists.xenproject.org; Wed, 13 Jan 2021 23:58:17 +0000 Received: from esa6.hc3370-68.iphmx.com (unknown [216.71.155.175]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 3b8047de-a1af-486b-98e4-17c432fefca2; Wed, 13 Jan 2021 23:58:16 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 3b8047de-a1af-486b-98e4-17c432fefca2 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1610582296; h=subject:to:cc:references:from:message-id:date: in-reply-to:content-transfer-encoding:mime-version; bh=Jmr1N8GGLXGJbxrSQofcOb4hO7vPAvVc9kc2NPbvvJw=; b=iZuayIB24MmaLzJFC0X8YZreozQEYOOnBnHVOcctPg2n8sw7ozN8q1y4 tvciOb8JmnA2QaaAEssBjtahuirrbXXGne4C1qNGn0Ga2SYNYAA8RR809 bBOlRHlroVtlawBkkv2wujYpFV0pPdrco4961mVPKPs2Uk2XAir+Y/Jyo E=; Authentication-Results: esa6.hc3370-68.iphmx.com; dkim=pass (signature verified) header.i=@citrix.onmicrosoft.com IronPort-SDR: OVsMO7QtlJGuAV/ZHW7vjm9y4w2f3i9sU3az/ekevqegxi+KFmM4yKe0aPQZcT7EXmQpD6eXB6 DZQ/GCBbtpAUn/u+VGW7hoZiNT9aC4XvBJD6yaD/ttwVxAx9l2k1NABTDwVYgfIHFvzxLIpKoX qg0AfzegQu/IaLQF+tyiibWLIuzqXPW1GAMI/YKCKLmNA14HW0syk7iIgmtxsHYjNC14Wsev9q use/WN7e8rv5LfSe2utLVHy9ufd+OonFo+OLsOx7o5qGIZhLJeLRbDrWdmXi0kFRsjc8/V+iCL uiI= X-SBRS: 5.2 X-MesageID: 35267471 X-Ironport-Server: esa6.hc3370-68.iphmx.com X-Remote-IP: 162.221.156.83 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.79,345,1602561600"; d="scan'208";a="35267471" ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=gIDFDj+fAu9POhTpz6vjjA0ipK5nb61AZjp8u4GRjfILLcaL0G6nrCQN8rsxmMQlpwtmhuPtAeg/fu8whX3lDiWHhIL8oK5vwEIVPVTBwDIyPQ68s/groyFWazZqoymAb80oLkm1eVLMByG00k9Kj23ss+bHPUVwyyVkwxplz0R+472XLRCbqWCrlj1N32huUDdJgevsN82NjLCI0rKxO5BUrh7IUtfn2FAXth89vfg+blIWJ4Bv6ZBTXStZINVAm4fo99fOj3KWpC90QWzUTfcRRlLqX+Jp/vHNI2lBtSOd6e/0L7wAMLurS31CQ7roRhx/Qffh2pQCluVNvKEuKA== 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=JEm9ojvtREQkn9StehDvgBy5mR2MLp+t0ipJHvgVba4=; b=NAG2t3kSyR2VszpJnJNAtiTOAj6aeT03sRICDO0S+bGLgOQHIf2sftQdPFLli/jE7Er0IZErvezjAMfFh4iEHyep1St3j/TkzaczOgMJ616huxPo+BCiH/zJqXlBEcdmbj45/7IJ0AFq04XKPYBEj9HC+arVvQ18kVdcnHOtvvvTduumK/6fOY+oroqfWt+CANxgc8514zyhJrWmXeo9XRn4UEOI1sKyR844+uLgzNXn2snTHtTVCBXyWQkRPm1GHjTFasF+jLtCLKQGfWEAMYhy4Jh5sns9F1OEmNdiHzTLal8KKlhfHjQi4Jhwg0YTF9jNmVtaHFiSHCUMVkdIfg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.onmicrosoft.com; s=selector2-citrix-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=JEm9ojvtREQkn9StehDvgBy5mR2MLp+t0ipJHvgVba4=; b=c0l39kJqqyVmjOs2y8WWtsrClIfkj4d0RtBCiwgONiqs8a2OA7ZHKgHM+9d55153y0aRPbPhfA9ueb8ZNUnuGfWf262rZV+HFqFArIi665BRuomfRuAzKbX02bY5cytkTOxYI6RM0lq1hOOa9jaRbudOU4llqBvQydpps+7t2qs= Subject: Re: [PATCH 3/4] xen/domctl: Introduce fault_ttl To: Jan Beulich CC: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Wei Liu , Stefano Stabellini , Julien Grall , Volodymyr Babchuk , "Tamas K Lengyel" , Xen-devel References: <20201223163442.8840-1-andrew.cooper3@citrix.com> <20201223163442.8840-4-andrew.cooper3@citrix.com> From: Andrew Cooper Message-ID: <4d4ff9d2-7176-cb21-d594-56e993aad477@citrix.com> Date: Wed, 13 Jan 2021 23:58:04 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-GB X-ClientProxiedBy: LO4P123CA0072.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:153::23) To BYAPR03MB4728.namprd03.prod.outlook.com (2603:10b6:a03:13a::24) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: cfe3bae9-f4e0-4ab6-779b-08d8b81f151f X-MS-TrafficTypeDiagnostic: BY5PR03MB5112: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: +qa3JtEzS8CXqANX2qHTVKZ/UtxxXludz7OZ0e52Tpovd9gggZPHFBeoNBSC9aeTxNXE68bzhGitLgWD2dvu0iv1AUEl9w5GA4wrEp2u+9Y5TiXXouDdqmTei+TbuDXX4mdEHJHn7t1N2E6JW3et80QWYUt3J64+9ATXC/eXEh/UPuGU14dgyslhirc/9wkabC+YKyPUlWnmAYd+MVfEfHIyApvVIF1H4s0V+EGPqPhsLtXaObsLBgUYcJAiacLBBw74IeKZUZ1F0Qu/1jW/I8ifqDUFbFQAj5S70zNr2qSY9G5nncENyvu1XF5Z8J8Z7uTd8ESqMeT2UW4rkhl7G3o6hkN+4FmpMp8TyVdR9wIKzWD9UzX53xy/JBdaL4DYO97xj1MQvI4ebhTsqD1dIiKWh+wCElGkfuFqcgXBLYV3WI5SX//aY6j2Myo9v9N20XIUQhTIcnBq2i5VUD1wCdd4UedhseCg0rQJvWfb2HY= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR03MB4728.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(376002)(346002)(39860400002)(366004)(136003)(396003)(8936002)(31696002)(2906002)(86362001)(31686004)(54906003)(478600001)(83380400001)(316002)(16576012)(956004)(2616005)(53546011)(6916009)(5660300002)(66476007)(6666004)(66946007)(4326008)(66556008)(36756003)(8676002)(26005)(186003)(6486002)(16526019)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?ZFIwSTFXeVVBMjFoZ0xoSTVLSEUxRUVqQ3pFb1FQalVycXBWUU4zMkpBcXZI?= =?utf-8?B?bGJEcEw0ZVlXUTRMTzlXKzBqbjhhREVJcExCT2c3eUp0N0dDbVF0Z2RQSUZE?= =?utf-8?B?VEdiTGFaMDhPWlV0NHBLSVRkeUM0QkFrU29wNkliNXJmOWFYNFFMZGllM3hw?= =?utf-8?B?dndGQmJZZ0Q4ckVpVjJUR2ZuQ0ZrelZMMEg2dTNNdkhPd2g3bTlLcHM3MTJS?= =?utf-8?B?YngyS3F2UERCaVo3STN0cVYrL3FlK1g2a2pLOFlremtheGNWUlhGODdJRWx0?= =?utf-8?B?RzRMaklUazMxOVBRNy9QUkE4R1NqWFN6aDhlU1BOVFljeXZkT1IrQVpNY1Bm?= =?utf-8?B?VXg3ZnlHNXJLUFJRclJzckY4ZFZTNm9xVWd3RkZTRTM3UlYzd0EvditIZk1x?= =?utf-8?B?VURua0xvUWNXc0pITmJ2Vmc5MG11TG1OazVOd0VUVG1JdVI4dW1nRmQ5MzZn?= =?utf-8?B?MDVpdXdkdHJlbVdqQ3NJelRwS2dyRWVEYXN2ejlaK1ZsaG5iZndzYkZDeWtu?= =?utf-8?B?a1FkMUJQb3dUc3hZS21IQzAzQ2hpQTBuM1YrRUNYZEZTS0syTllMRFQzYUpv?= =?utf-8?B?N1diNWxzN3RTL1FKN1AwTGwzZ3lFMW5zNUd5bTNGM2xSNEZhY2dKQjQvSWxU?= =?utf-8?B?NHdXRlFGU2RuRGVSUjh0UXlPNEVGZnRUZkZmVitEeEE0cU9JQUZPaDBJeUxJ?= =?utf-8?B?Nk9WYkdTRTNRbm05UjhsZWYvNlQ2ejRPNWVON1M3T2lVVnFkcW5kUTVBV3ZB?= =?utf-8?B?MUdpZEFLZHQwMy8xRmcvdzNJckN1YkpSZzRJMDZDcERvY0FWdXMvSDNPVWJB?= =?utf-8?B?RHBkZjlha2I5SmF3UCt5Z3NNRXFoanI2WmpYMFhtSmFTbWdLenBvWWJiNm1k?= =?utf-8?B?K3BRdnNnWEFrQThvZFViWEgxNmJ3UldZWjFUM0hwN29Ya2RxTUd4OU0vOHYw?= =?utf-8?B?NVE4dEMzL2FvYUNsNC9PTGdLUjQ5QThXSllFcHpNbm03NzdiSTVNT2p3UFVn?= =?utf-8?B?SmFCRHYwR1JRd21zS3dNZEtvdERZcGFLMjMyN0ZHOGpVWjUzTkY4bmNIcERz?= =?utf-8?B?SHdwS0JlNWV4NlRxVlVWaU9oMzdUSkkwM0wvRkdXQWxPTHB3YXdsM0txblBO?= =?utf-8?B?enAyeFdzQ1lPUnoreFFteTFJUjNydEJwNy82eVVqb2F6NWtXNWwwM2dSMVh3?= =?utf-8?B?QUJYRUhMVTVpZEFvbWlJK2VJSmJqVWxhTWE0VHNTbXlReWg3UDdoRnNjNCtM?= =?utf-8?B?VUNnR0FMVG80M21TUzRrSzlldUorMnRpZXg3eWt6dWJZU1d6b1cxR1NzSHlJ?= =?utf-8?Q?biGonisv7aUI1i8KXilouCcx0GdguLc1gk?= X-MS-Exchange-CrossTenant-AuthSource: BYAPR03MB4728.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jan 2021 23:58:11.0156 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-Network-Message-Id: cfe3bae9-f4e0-4ab6-779b-08d8b81f151f X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: YUvU1NPNkJ3m+8eg0q/1oDdAsHex4ZcXIAt2oTjb838Oo5aqJcyeavmwCWVc53J1K5NQ2QUk9UeCrkhn8Yf5GT/Z3f1vUT9SYtHKaOfEhLM= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR03MB5112 X-OriginatorOrg: citrix.com On 05/01/2021 16:39, Jan Beulich wrote: > On 23.12.2020 17:34, Andrew Cooper wrote: >> To inject a simulated resource failure, for testing purposes. >> >> Given a specific set of hypercall parameters, the failure is in a repeatable >> position, for the currently booted Xen. The exact position of failures is >> highly dependent on the build of Xen, and hardware support. > What about other kinds of resources, or ones only indirectly > related to memory allocations (e.g. where we don't mean to > associate them with the domain)? I intend this for "any fail-able operation", not just plain memory allocation. It's merely that memory allocation is the simple first resource to go after.  And after all, these 4 patches alone have already identified a real bug in ARM's dom0less logic. Perhaps what we actually want is a general "bool simulate_failure(d)" which dalloc() and others can use. >> * I'm thinking of dropping handle from xen_domctl_createdomain because it's a >> waste of valuable space. > Looks entirely unrelated, but yes - as long as Xen itself has no > consumer of the field. The more that there already is > XEN_DOMCTL_setdomainhandle. It's purely for pretty printing in 'q' and handing back to userspace for xentop, et al.  Nothing in Xen acts meaningfully upon the value. >> --- a/xen/common/dmalloc.c >> +++ b/xen/common/dmalloc.c >> @@ -10,7 +10,13 @@ void dfree(struct domain *d, void *ptr) >> >> void *_dzalloc(struct domain *d, size_t size, size_t align) >> { >> - void *ptr = _xmalloc(size, align); >> + void *ptr; >> + >> + if ( atomic_read(&d->fault_ttl) && >> + atomic_dec_and_test(&d->fault_ttl) ) >> + return NULL; > Perhaps we want to introduce Linux'es atomic_add_unless()? Possibly.  I definitely got caught out by the semantics of atomic_dec_and_test() seeing as it has an implicit "!= 0". ~Andrew