From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) (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 AF8E01D6193 for ; Thu, 19 Mar 2026 18:30:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.20 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773945025; cv=fail; b=pm+AtPfsT3RRApAVyxPCKjABnS2PoTPraPqH+V3rlFLXkjYOfZSisMgScdMMOd9iAFca8BsIAd+Bm7/vXBc4NVnF2sP05WAJ6hxldwK6S0OcautTROtvRcjuHXgFhp/x8S18F5htW3HZSi6jV1JPhRjwGEbZ/tYnOwxODjAcem0= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773945025; c=relaxed/simple; bh=9xfKkopdQrYkC4tyC3cQil5EFI4BIoUA8khUuJgDtSg=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=TvxeQVFu9bZYzEGO2uJBmzlTGzv4MD8spDZBguWxMxF1mazS21+ybCnsyMAqhHPV8EWXq3KKfBzX1aZ6vWyCXIyb5t2R3abfkcRqcpulN2blTWqWRkcnZHxzFJTH+SYKgjldmYjiEyhOefD0lES5etw6zSw2+PYijM08b4nzCi8= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=LeqoWFj0; arc=fail smtp.client-ip=198.175.65.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="LeqoWFj0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1773945024; x=1805481024; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=9xfKkopdQrYkC4tyC3cQil5EFI4BIoUA8khUuJgDtSg=; b=LeqoWFj03+vm/EPZdLH2oX1IB47Dy7bk8wjScTncyTDyxJmrmGznac+L rGaDZ/sPiVsvhwf9YbNZgIKvXDIa9TRol6kRsU7ZHZ2u8zVX9BXOuoRBx GdVn2Hrm6dYlp5Ka8MmBRwYN4kxuG1wWX07ZLWv53KibjfwyLQ/tj5zGe RlTyWeJRJ9gdukkWb3U/CmBqmbw6kxyIo6vN6DnzcSmggKtZH2XyF5nST /Gn3sy81j9stmqcz9paielep8384iAmobk2Tw1utMFTkPmAMwJ/3kp86E 3vl9FixPJwPllk55ja0Gj6RS1ALBvWO3q3W6jl8yA+lNGKsTBn8VIgJr5 g==; X-CSE-ConnectionGUID: lM4sQkz4SGmMHJ8LE8KOlQ== X-CSE-MsgGUID: WcbttsXYS7iR1QLMLdC2MA== X-IronPort-AV: E=McAfee;i="6800,10657,11734"; a="74729462" X-IronPort-AV: E=Sophos;i="6.23,129,1770624000"; d="scan'208";a="74729462" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Mar 2026 11:30:24 -0700 X-CSE-ConnectionGUID: XP1e0IbzQzmLkKytZ0aRyw== X-CSE-MsgGUID: 3ZA4kuOBSaqLBP1c0JKmeQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,129,1770624000"; d="scan'208";a="260943079" Received: from orsmsx901.amr.corp.intel.com ([10.22.229.23]) by orviesa001.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Mar 2026 11:30:23 -0700 Received: from ORSMSX901.amr.corp.intel.com (10.22.229.23) by ORSMSX901.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Thu, 19 Mar 2026 11:30:22 -0700 Received: from ORSEDG903.ED.cps.intel.com (10.7.248.13) by ORSMSX901.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37 via Frontend Transport; Thu, 19 Mar 2026 11:30:22 -0700 Received: from DM1PR04CU001.outbound.protection.outlook.com (52.101.61.45) by edgegateway.intel.com (134.134.137.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Thu, 19 Mar 2026 11:30:22 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=bHDjeGoNEFcWHH+KkVeJPbu5QHWpW1rH1zAmmgnIWB3uXMDdK6eVfyDRjpyfn2KANuBEBTOTJ9zd7Wc58ECcjNBIrJzisXG35aYi86ZxpMgmMhT4AT0191AbJ/o8oym0qKPkbkw0J7MQt+KDF7a4u0C2Qynu2KuY0x/7cp87JTfkuM/SG2bXK6cToxrcaWbCpOf0IRs864lHTMVrW7taN82U+nvZi913Ct+VOuyG17TX0esY6kcjZp3GoDay4numUutaFR/x/aorz0SRNZHvy4NxkRTZz1YDOcY5EIDUI5mB5SH/FZq0nPiOa9DXRnBnP5NaMoq1ttRbMrC3bVXKsQ== 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=zY8XVD1SHweVkhTheLtSMk5P6RJTkee0znm5k4YAvvs=; b=KLVFM7MMvI/7D6oppwCYsrrQjcSqEIxHkqlt57HZJf0A3G9sY3BwWFwOX+PWYKV7bQU7123f0auH9GnJ8DMsjJhxcafbnslxrA8e4AUziEnsraPNKpccz1qdTVh5911uHosfeudFu9jwLqL4wjAXOE7UQm6Oj5OES8OAqnNsvW+9m0S/pYYuGGRs3KYfQDwfjAJa2z64fG4R95wI8CyLUi3/jR5EPmHu5P6ZRDZ8RfY4WC4usvPmHgyPvmjfXOsa1j3DJq5d1LS6Oa+9ucT7C7p7pl/+SEs0VYWy6c2WZ+uy4UV/Ig6kGWOoGPpqqoMn6f9A6KfdqNrQB3ZcroGPIA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from DS0PR11MB7997.namprd11.prod.outlook.com (2603:10b6:8:125::14) by PH0PR11MB7561.namprd11.prod.outlook.com (2603:10b6:510:282::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9745.10; Thu, 19 Mar 2026 18:30:20 +0000 Received: from DS0PR11MB7997.namprd11.prod.outlook.com ([fe80::24fa:827f:6c5b:6246]) by DS0PR11MB7997.namprd11.prod.outlook.com ([fe80::24fa:827f:6c5b:6246%4]) with mapi id 15.20.9745.007; Thu, 19 Mar 2026 18:30:20 +0000 Message-ID: <51f5dc8d-e130-4769-84e2-588553c7fde3@intel.com> Date: Thu, 19 Mar 2026 11:30:16 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 0/2] x86/vsyscall: Tighten vsyscall emulation checks for a #PF fixup Content-Language: en-US To: "Edgecombe, Rick P" , "bp@alien8.de" , "hpa@zytor.com" , "luto@kernel.org" , "dave.hansen@linux.intel.com" , "x86@kernel.org" CC: "linux-kernel@vger.kernel.org" , "jarkko@kernel.org" , "namcao@linutronix.de" , "peterz@infradead.org" , "mingo@redhat.com" , "Xing, Cedric" , "Luck, Tony" , "andrew.cooper3@citrix.com" , "michael.roth@amd.com" , "brijesh.singh@amd.com" , "tglx@kernel.org" References: <20260313192327.2089471-1-sohil.mehta@intel.com> <73556a5cf5f932fb2034cd16a8c06de773f4a73c.camel@intel.com> From: Sohil Mehta In-Reply-To: <73556a5cf5f932fb2034cd16a8c06de773f4a73c.camel@intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: MW4PR02CA0023.namprd02.prod.outlook.com (2603:10b6:303:16d::16) To DS0PR11MB7997.namprd11.prod.outlook.com (2603:10b6:8:125::14) 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: DS0PR11MB7997:EE_|PH0PR11MB7561:EE_ X-MS-Office365-Filtering-Correlation-Id: a08d9e3d-49df-4dc6-401d-08de85e59336 X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|18002099003|56012099003|22082099003; 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:DS0PR11MB7997.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(7416014)(1800799024)(18002099003)(56012099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?dVF5MkFONDNyNFZmVXlnUUc0Z0dKVURSbTg3NU5yaXpBTHA3MkJJUDNzV2l4?= =?utf-8?B?RFliTHRmSzNZMERodUt4bTFQeCsxbCtYcWV0TG5kTEx0VmdKcTJiUDEyQS94?= =?utf-8?B?ZWhQdytjSW9UeC9FTHQ2d1h5RnlpUFY3Z1FuY1diR2c5OXRNUGpuMDRRalIz?= =?utf-8?B?cVlTSWNTZG1FNWp4U2ZhRU9HRVV3WHJNYUN1UlpQSVZYZVp4ZHVUcUtMQjhj?= =?utf-8?B?R0lKbnZSVytGUVQzaXh3Z0d0dno3UUJ4Uk5KZVAvUFJpWnpGNDloUnFXL2Qy?= =?utf-8?B?RHBITitIWTFFK0RVemlMSjNIQlVJU1UvRDF1YmpDbEJWb0hZbklBZjM2QmlF?= =?utf-8?B?ZmlHTEcvR3JrMFNJMncrWlh5LzJkOXkzb1ZiY20vMDF0bjk5eDNOOS9zb2xC?= =?utf-8?B?QWJFV1JsSWw5S25RblNsL054TWw1N0JQUkRCejFxekRURVJENnZNbDgrd2Jv?= =?utf-8?B?eDVJQWxtbzk4MVFwTEZaMmQ0WU53QW96TUx4R3dNcXRYOG9YcndzaW8zQjhV?= =?utf-8?B?YlJZSmhkb1BWZ0QrcHdiTUJGMm1iNXNZczIrOUY4SGwwcUNackJSM2RNelBE?= =?utf-8?B?YVRKUEdpNExjNDlWWi9EMnROUDNhbmRFdjlQaWwvY2JEanFGbGR4WnoxcjZU?= =?utf-8?B?RS9mL1V3ekJhZlZGMy8yMTFKMERLTXVDRWdEZUNURUJaZWp3WXpRTUkvaU5S?= =?utf-8?B?Q1h1d2JFYlQ5Vkp2Uzk1cXE5bG55QlRpQ1lTcldQSm1RcGsydVdVckpkMnk3?= =?utf-8?B?R0x1MmdPNVBLY2Ztd093MStzbzExOXlORjJwc0l4bzJMSXN0a2l1cGZiUTlE?= =?utf-8?B?clZadjVvVERHTXdpcm9TN3FnOVZicW15N3NrVmxoMk1vWGQzVUE2dDhrUGVU?= =?utf-8?B?QnFKbVI5VkFpSEh5RFlDenMvZWQxZ1ZWWC9ublJmRUdxQVlJV1BiSmNBUXBm?= =?utf-8?B?dWNqQWJCZmtwTnM0T2svb2toRlBrcmVjajJ6aUhsZzc2UVRnZVRENzNlNnlh?= =?utf-8?B?bUFZZUFKbVZTWjlFRVNacUlHdVFzTHF2NVRUNzdtYzZjakhCYXR1L21YaHZB?= =?utf-8?B?QVM0RGhLZG45dE5kMzNGYnNyM09uRzFPcnZpVG50ajM3ZmM3TXhlR2cwZ2Iy?= =?utf-8?B?TEFWby9BbUlxMzU1emtNWFNtenZQNDBrdGQ2b1M5c2FqWDJGQzhZdW1Pa3hx?= =?utf-8?B?T3pJUnhoaVlnKy9zWTZoRVlZTWJhbTBIMFp0U1MrQW9hTjlKN0dyb3JNMEZD?= =?utf-8?B?T3Q0OTVWdUU5N0VtZ05mbXFuZW5jUjlwNExuaTA0TS8zbG54WnVuK0R5d0Rl?= =?utf-8?B?QTA5eHB0NnJ1WDAyY3BsVlpGemNkLzVhUklLODBqcXJNWTl4MXo0NGRESzZq?= =?utf-8?B?a3ZyZndwS3RpSmJ3ZUhHZ05ENmw4UFJvMkQ0UlV2S0hYUERrN1luRktnYkQw?= =?utf-8?B?bCtUaHUrcWVQMDFaWUNUVEhRU3hsNGdPVDV0Vkt2a1ArZE1mSHBFWXlGR2RX?= =?utf-8?B?VWNiMHZLS1k4RGRGOGxUY2xtQzAxYzFmL1p0WU9NRmc5NUo0eEhsSUdUSHV0?= =?utf-8?B?cXEyS0hxbmZMcEhsekJwVU1meGVUZXMxRDd4L2hDMlc3aGtCN3lrRUFhdDNS?= =?utf-8?B?UDFuT0JRaTdsOUd6dm1GV3RRNXF6M1VkdmF3bVFIUEVxRmE4bURVS3p2dVV2?= =?utf-8?B?Z1lDa1VYTkpEREtSN21HVWszK1ZKU0RQazRhWGdZSlB0Q05wZFFoVk5HckI3?= =?utf-8?B?K2EzdGR0bnpXT1JIRjdXN1ZpQ1RmYzR5SFVJMy8wTDgyMDlHelJhVGs4Vlg1?= =?utf-8?B?WXJOdUNmNkZwTm5Kb0p4RVA5bWc0VndiRWl6WXlhUG9yMnIzSzU2cXFKOU9K?= =?utf-8?B?L3hvQnNFRXp3dDBWdjQrSnZzT3JCdU9yWmVYQ3NRR3lyMnlDWXp6V1BDY3Zm?= =?utf-8?B?bDlLR2NyM3JqMnFINFdseVhjazhHOGxjMGxoVnEwK3dMWHZ1L3V2SmZ4d2dG?= =?utf-8?B?VVBtVWc3T1QyZHM0WVBOd1NKRkE1Z2k4WlBzL0RYZUF4TmdacWdiWUFFdDhx?= =?utf-8?B?ZE9MdHp3c1pqMC9na3ZzMURWclE1TVhXWnhadUZUcS9udVpWUHNPekhPcTNR?= =?utf-8?B?Umlib29qUlVoUC9yY0c2QmZsQmdEY1VSZmszSG16YjhNQlpnU1JjMk1aTWxM?= =?utf-8?B?cmNUY1p2MFQ3VGZEQVlVdERYUGgyK0xqcHB5V1NGeGJqZXRvQ3pORkQ0M2xL?= =?utf-8?B?azNnSEpSTVk4RHlwbTFPN2UxWFJKUFJZc0FpS0ZzVFg4YkY1RVZVRXF2dm42?= =?utf-8?B?djhhcU9OdFpXVWt2RHlCZmpHQS9NS0tnYWlhMjBraWlKM2ZQRzdHZz09?= X-Exchange-RoutingPolicyChecked: TnIRRw8GLoipfjOdJ4BfQbiCQzIqq8j9102pcPzlhc3K5CWtdBApndqdPk8NsS0HwmB2VtPKzuuHv2QGJoHJ7hBwZNm9qYCzRNBN/bEt9OQ9PF1JH129Vkq5pomuVlVg4VSb2IVm0w/HyEuHG4OGYUxNDJr2m9GqAHY2b+DEM2f/FFG4vzjse0TKwqjJRk4Hz/A1F0cR8NEqtc3BNE3QMB32Pf1nr8ypQScBwu5wUv8GphqzKlA2HUV/uYpVh6hBKOxhhS1nydDTK871bI04uxQE0LQKbXz+/iaMsB5t7z7l3DTkHU0nYsjf8bRIfKR/W0u5B+PUUy/RTFr2rEyFcw== X-MS-Exchange-CrossTenant-Network-Message-Id: a08d9e3d-49df-4dc6-401d-08de85e59336 X-MS-Exchange-CrossTenant-AuthSource: DS0PR11MB7997.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Mar 2026 18:30:19.9253 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: +4Jyr7UGUDIGTiaClVTGh2TxRfGilDbhpg4F/rZHOzNf48WwsWeEzmnVhP44bg5tR2z98ErCsGKuWH+zS0o7XA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR11MB7561 X-OriginatorOrg: intel.com On 3/18/2026 11:47 AM, Edgecombe, Rick P wrote: > On Fri, 2026-03-13 at 12:23 -0700, Sohil Mehta wrote: >>   X86_PF_SHSTK: I am not sure if we can have a vsyscall page access >> that results in X86_PF_SHSTK set but doesn't have X86_PF_WRITE with >> it. If we cannot, the current checks in emulate_vsyscall_pf() will >> already reject emulation. > > There are shadow stack read accesses. This would be pretty hard to make > happen to the vsyscall page though. I think it might be impossible. > Ptrace should reject kernel addresses for the SSP. And I don't know how > else you could get the SSP pointed at it. There is WRSS instruction, > but that only generates writes. > > It is probably fair to say userspace will not care about the case. > > Thanks for the insight. As userspace wouldn't care, and the cost of adding the X86_PF_SHSTK check is almost zero, I'll keep the X86_PF_SHSTK in patch 2. For the next version, I will combine patch 1 and 2 as they are essentially doing similar things. I am still unsure about X86_PF_SGX and X86_PF_RMP. Unless someone with knowledge chimes in, I'll leave them out of the checks for now.