From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM10-DM6-obe.outbound.protection.outlook.com (mail-dm6nam10on2088.outbound.protection.outlook.com [40.107.93.88]) (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 A416C186615; Fri, 23 Aug 2024 19:41:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.93.88 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724442096; cv=fail; b=Rv3MAIN7zQzB4Qrkc08W0cB1YKc9nHnP3OzrCN7vuhaYVMcUKh96ls2eRqE1qqq3b7FiKzqSfXWN5c47o9V/4XoPiGeD3Q2/mr3YEp/sF5+/0Hduz4y9igFGCbFAMabHKrZGLs5oqYCQ8TfGBc9c8LACtbUF+HoqwCPuPmTyxrA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724442096; c=relaxed/simple; bh=bqdGYk1hKotWiliSUnCKOXq7bB4Oca3aRo1oGS7QLnE=; h=Message-ID:Date:Subject:To:References:From:In-Reply-To: Content-Type:MIME-Version; b=id5P7qBcuiZEdB1OXf2LQSUju7PYcN5WKhAx4qvFLIYT2+CwO6qn1q/VzEK0abK6dt0vnShz5XbI4E1jvx02GgkkF28yxTjlgG02zTq4GdHdTSMhOJoDTCTC/3tZp/GWxKBQ52qN4CD1TJ0KXDFVjJb4EGJkQXJiEMy5oXDStWk= 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=KmPfzK6r; arc=fail smtp.client-ip=40.107.93.88 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="KmPfzK6r" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=bQYT4BSPeZrOKUatPF8UdUF8zzWQuo7BbkhjzZqKpPxma/NYd/eze1qc7Ps/UwzYey0jNMMc1AG7KEhAjBj6m4/ar25qEU6nr2uqrmoITKMQjS745Fy51ZZz4mpnKLa8XAjpeEYeUCLBhYjJn1SNPQIWzviiz5vBeFObsauBaXPMv9YuXzniGasuruqS3OYH4LOEmbE4gvkZoMIklA02ySB8mJgYM+Ds6Nl4rPZEgN5y9hpxHu06pkGi0nZ4cN3ekmggkeK6uq/CtIi5TO00Ky0ve4KXM0AhSYAjNl2LW35rQwYYQBpBlCab5CbhWO4gRv0Q3ZWx9GjFo8yQw/sWBQ== 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=oDaCQVMckZzCjLs9a0kH8wiwq6McgkpoYSlm+rQ1ewA=; b=kQ6hVJjXo9rIRczoklqAw+gVkMuU71yFoQ0U1uHracKzfcr9lRxOnp7KWYAj5WvXy0ALls0v6JqAdYML20v4e3u4vaDS4yOiDMZkm88zf/b4rpMKgzfCbuRSOh4YS5H764L9+xuhzoSrmOgNv+HtJ6kVRXw+BFhU5bi83zgtz17arOfYEg2lbzLhifTiT9WgFbSq1KJabCJ+vIoycK1wuwMEvPbmPJRWrrvfJGhiFJVsCKgv3xpHk3QzUKBhxDFt0PKpntu3V6TJQCaNLAD6i5KLMM5VaxO76tSUj1FGlvhluczOu6V2aCbz4tst2Cq9AnNqmfw0rJGwAeR2+2gmJA== 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=oDaCQVMckZzCjLs9a0kH8wiwq6McgkpoYSlm+rQ1ewA=; b=KmPfzK6rPu/uFl5Lr0h2P0Q7BXND7p9lH6O/bQGa5JaZMhbBW11cThHcf/CxjmdBrKIkh+76hoR+Q0DCCOFi9LqxH1c83XNd2L9xHEg2n9GrXL0Rhgf2VtUEq61w9JV6Y2ffGqnhuNyQcaxXJfQ2vobN6cakbn0ZBBNPUBKyWzg= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from DM4PR12MB5070.namprd12.prod.outlook.com (2603:10b6:5:389::22) by CH2PR12MB4280.namprd12.prod.outlook.com (2603:10b6:610:ac::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7897.18; Fri, 23 Aug 2024 19:41:29 +0000 Received: from DM4PR12MB5070.namprd12.prod.outlook.com ([fe80::20a9:919e:fd6b:5a6e]) by DM4PR12MB5070.namprd12.prod.outlook.com ([fe80::20a9:919e:fd6b:5a6e%5]) with mapi id 15.20.7897.014; Fri, 23 Aug 2024 19:41:29 +0000 Message-ID: Date: Fri, 23 Aug 2024 14:41:32 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH v3 0/4] Distinguish between variants of IBPB Content-Language: en-US To: Jim Mattson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Sean Christopherson , Paolo Bonzini , Pawan Gupta , Josh Poimboeuf , Sandipan Das , Kai Huang , x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <20240823185323.2563194-1-jmattson@google.com> From: Tom Lendacky In-Reply-To: <20240823185323.2563194-1-jmattson@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SN6PR2101CA0028.namprd21.prod.outlook.com (2603:10b6:805:106::38) To DM4PR12MB5070.namprd12.prod.outlook.com (2603:10b6:5:389::22) 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: DM4PR12MB5070:EE_|CH2PR12MB4280:EE_ X-MS-Office365-Filtering-Correlation-Id: ea25a139-b11f-48cb-f0a9-08dcc3ab9568 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|366016|1800799024|921020; X-Microsoft-Antispam-Message-Info: =?utf-8?B?OWc0eFR1blFlbUZjYXN3T2V1WFc1UzNBSzB3dzhodXN5aXQ2MGQ1NUZHUEVX?= =?utf-8?B?cmR3OHRqa29uZnJMbUNSQkVYUU9Odks1U3hMYS9DZlptK0ZFWlNBU3dvTHZL?= =?utf-8?B?bWtLZFBqT2FrcVV6UTljKzk4ZkMxNlpYY3FHOTZ0SkUweUo0cy9DMk9DNHJ6?= =?utf-8?B?TGlPNTkxeEt6cUpwejFicmYwZGZvRm4vNnl3VnA1czFHRFFOTXlvMkQ4Ujl1?= =?utf-8?B?MzBMbFNUQmg4cWtkZDl0WGpnNlVOMDhMWjgzQ3VqZTI1T2R1aitvREFmMGMr?= =?utf-8?B?YzNIdkV5SGI5ZnVML2ZJK0FudDE2aEx3YkxMN0NON1g3eDRSYytTTW5yR2lq?= =?utf-8?B?VDRiNHM4cWQ1ME1oOGFjSUlyYmJSOUxaemxubEE3aTU5bExGc3h2cUVtV1hG?= =?utf-8?B?ZXhCM3NrbVp1NDFCN0FwL1pzQ2FhRFRxTEpuMENpeEQ5cDk5SzR2VGJud3hB?= =?utf-8?B?cUtoUnNKN1p3MGxWYXdxT0ZiM0cwaVZPQTdSQzdWcjZZdzJkblFSc0M2R3cv?= =?utf-8?B?dTNLTmdXR3RmaTdZdzgrcmR0VHEva1owZm9WVFE5ZFpqUHZyWTRCQU05Y05y?= =?utf-8?B?L21wd2ZXWlRWOXVWZmFFdW13TFhGY1lZNlVYQlptTGg2TEpkYjU3Q1Y3REs5?= =?utf-8?B?d2RFcDlpM01LeW1wZTdlNzZtS1A5ZGJYRGhiVnRiWi9QOWpsTlcvMm9yeCtX?= =?utf-8?B?aEhsL1RyMDR5OWF6b3JYMHZ0OGE5K2tRcUJRT1U1TTJmSjRWa3NUT2ZWNEl6?= =?utf-8?B?VXA5VWY0cit6Mm5EUEVOQTNBeU9OY0NsSzduZ2xWTjVMaFRWM082eHptM0ts?= =?utf-8?B?a2EzdGVHc0cxb3p6aG9DYlpKalkwTVNoajhDblRRdW5TRUVhckhhRnBTdlI3?= =?utf-8?B?MFBEVW5laFZDZzZURE1kVmtKcG4wVWZrOFJMK2lBUHd2eHRDSzh6Wm1hUlVa?= =?utf-8?B?SlBjOEZCMXFNLzI2QVBQaDlqbjkxbm5nTGxOYlIxT1FySTF3TExKbWc5OXFV?= =?utf-8?B?VUVqZWRpZU5HWmJsaHE1SFBnT1c4MjFRNklTcFJLSW03NFRwNmxSY3RUYmJY?= =?utf-8?B?dWR3QjQvcFJBK2IzbGNGeGJDR1M1Vi8xS3J1L3lKaUlzclRnWE1zbS9xNDlw?= =?utf-8?B?Z200QVBSaEZyZFV4eXZET1hwd0VWcHNVTVJpUVVkZk1IZHBPcjNpbC9pT2dj?= =?utf-8?B?bVpneWdoWHJKQ2dyK3RiejQvMm5hdWNoZWN5T2txMm5CMnVvV0VDRHJwL3p3?= =?utf-8?B?V3ZrYnpGTHlGNnBaeFY5WktYaGRKQmNNUm9yYXNJNk5LZXZZTnlKWmUxeTU0?= =?utf-8?B?RE1JQWl4QzJibzZScWJVbTZTeGJ4c3hOS3NremRreE9tNmliTHdDc0VnRDNp?= =?utf-8?B?N3BsYnZSZ2xtWlhNeWxVRnB4MDdRR043bVFlNDBabE1UclRmM01mSiszQXVH?= =?utf-8?B?blkwcWlTZGk3NkU4VHMwV3FnZ08ySHVBYXpGamh4WDVyOHUyNDgzZkk1bUNS?= =?utf-8?B?aTh4UENaMG9BdW1QRGhEeWU3MkgwSmkwWEdTREZVUDM3UXphempSNFE2U3Fl?= =?utf-8?B?M3JxTWk5VkNNWDlqaitkNVpITnRwNXBqU0JQL2lzRDlnaVdIWE9lZCsvWUxz?= =?utf-8?B?VVRveTVVQmdnMk9sTS80STZlZ0RGTEhPeHRyRGJRaVFMQU5sNGJmMVpndjZy?= =?utf-8?B?YjFQMjNzVmN6Q0l2ejUwTjZXY0F3d2IySmhvbHpBUHZ3cmtoL0RMNUpHdEVZ?= =?utf-8?B?TjV0bGJlRTlaTjRpcWw5REdtbFdQeDU4bEIrejA2cUttZ2pGSE01NnVWbXVk?= =?utf-8?B?VW1qaEVNVnVqRWlYM3RTWVVaYk41bTBlN0hRL0J0VTdtN3hGbUNJdndZbWh0?= =?utf-8?Q?d8pDU6+T0NAPl?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR12MB5070.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(366016)(1800799024)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UmFlNDBqZ24rMkF2SklzUEx3K1BlYnF6d2J2K0JTVkhwbXpUcHl2MnZXREdB?= =?utf-8?B?TVpXNVJrWVBCTnNia0RoZjlzMTY3MG8rbHZteVRsa1RDWWg1M0t1RVo5OSs2?= =?utf-8?B?bWwrWVBPSjcwVWdqQnN4QUVLUVBGVlp6VlRhNksvdm5RZ01XeFluODh5OC9I?= =?utf-8?B?cXhBTjVveEVYbi9KL3B2ZXA4S2VjekorLzB3RDgwVXRRWjF0RHJFQXJMbUgr?= =?utf-8?B?TnFmaG5oSkl6NFQvZDkzRC90dEhJdHRhWndGWVJ6Wi9tVm9hamRuL0h4VFBa?= =?utf-8?B?UkkvZEtkbFMxQXJoQmtsaFlpRlJJd0ZldGhqYjVXV3hSTC9nV3RUVG1Oc0JN?= =?utf-8?B?YjhyKzB0Vlg5dHNGOG9PZm5md1RnK1ExUUtSQlR1UzU3QzVZeFlFTjVIK3JE?= =?utf-8?B?OGhvYW5zNTlTZTh0OFplWU4vWURDUGNSbnRjdTZJVmJHSWZBN1RraDYvaC9M?= =?utf-8?B?TTJEY2NTZDlsYS9EZGppZFJYeG1sTWF3M3lnTUFOYm5XcDdhZEtaMS8rT0tv?= =?utf-8?B?YStlc2JBRFhnNHF6U2R5ak01cHlDOGhXL1FzR01kMGZ0VHkyMEw4eEhCRFpv?= =?utf-8?B?V2FBOXUyUFdPODJxT3diUEJBdnRRbldySTBjZU8rTFBSRWdvTDFwYUhyN3NR?= =?utf-8?B?ekp5MkFyenYzUWNvK21EMkc2WnNZTlVHOGNOZTlOb3VwL241OW00OVdwOWhx?= =?utf-8?B?MS9BcU1OWVBXeDAyL09USmVLeG5oQTZqRW5XdXUrVFhEM05iellLT0t1TkVE?= =?utf-8?B?eE9NSkpTRGt4dkg2bDcreHc1WHZyUHdIdHZ6VkpvM0JXbkhIbWRrRFU1M0xv?= =?utf-8?B?UWU1TnVmeHp0MHo5YkF2OEtaYmtMaGxDZEJjQUNOMHg2bnhzR3hZRkRMRXpF?= =?utf-8?B?dEI2aWJkWTFqMlFDaFZ3RStvOGtnRGNYM2cxaDBFeFFtaEZuY1MrTGRUQjc4?= =?utf-8?B?VzFDVG1OaUtyYlJtWjZkeWhmWmdmM05KbVFOL0QrTDhITDN1aUg4OXFjOEQw?= =?utf-8?B?YzgvMkpjSkh5QTViWWUyNHZsdFZ3VHFlekE1VDRZU3FjNnR3dFB1K25pUlJl?= =?utf-8?B?OFdjdUlrR2hqNUxXQzlreEp0TEw0blJtVXFmcDMvc0Z1c01nNFFpY1N5MUU4?= =?utf-8?B?c0ZzQUx1eGtWenppNGhsKzByYlhsSjN4UWhoR1FuZWp5MzZpT20rWE41cklF?= =?utf-8?B?dEhqYWxSdXJFa216bGpVU1hlVHVCTE9BSjVWdnJaKzJCUVVWT1BEb0kwK0dk?= =?utf-8?B?NzdYZDdoTGdjc0dNejJjVUZ1MkloVm5jM0F3bjE5VkVmbWRSc3c3T1VnQUhW?= =?utf-8?B?SWczQ2N1QXB4KzdGYmdtR1BxOUVscmMzLzVuUlZxMGt0ekhhNzVyRzhIRGQv?= =?utf-8?B?R1NjWjA0VWduNkhibkl3bFlVQkNibG5kZUEyeVFIcVl5Qk5nWDIyUTdyZEdK?= =?utf-8?B?OXdvQWFjdVlMRXRCRGNlOTVocHcxQTVabWZsaU9nZlcyY1J5dlZBMk5KbFFm?= =?utf-8?B?bG9OWS8wT09pZGtjN1BlcDNUQ1lBZWI4eWw2YkQxVEgwT1JsY08wUWxnY1B5?= =?utf-8?B?VjVOM09LVFVCcnpZZmkveU9xbGNyc0M2ZmprYVpjU2VRVzZmZm1NQjhvQzgv?= =?utf-8?B?bzhRQjUyeVk5Y25SQnFMVEpYWEM0M3B5RUQvbVBVWktWR2xscnJPRzNXaW1F?= =?utf-8?B?b3RGTU9TZnVpNDE1dmREbjUzcURkNDJOc3JVdTJTaHA2NDZjeDcrQXFOZ1NE?= =?utf-8?B?WmFnZzN6cmIxWm00NFcyMUoxdHpwT1R1dXJtaW9KekswUzEwVkViMUFRRk1K?= =?utf-8?B?a0RhNitpZjllbmFZNkpVdVMvMkRpR3g4YVdMVE9ZaUVid0d2bmpjYzJKd2NB?= =?utf-8?B?V3cxZlB2dG5zUVNXcVMwMkVnaVc0SlQxcExmbGxUWHFKMmlaMFMxSlJDM2F0?= =?utf-8?B?NldIMG12cnEyRFVaUkFBcXZuTldjc01NOTVDbW1SQjBCb1lkRHNPcGNEQU9Q?= =?utf-8?B?eGlaVElDS1JCT0Fnc29pbWtJcENWUG5iSDRNamxkMFdGSXczYVdMb2RmVGxx?= =?utf-8?B?dzA2SU9ETHJTZThIYVlDUEVRampLdjBvSUlDWEtlL1hqRjNTZ0EzS3VFWUlU?= =?utf-8?Q?3Q4AW8rJolUH6vPrta2JfbJPm?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: ea25a139-b11f-48cb-f0a9-08dcc3ab9568 X-MS-Exchange-CrossTenant-AuthSource: DM4PR12MB5070.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Aug 2024 19:41:29.4150 (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: fEU1PGUFjEjAjRmR3ftqYfIDpo8J+NUNTtXLolLneoCiNX72NX6vPF+K//Imo4LZCufw3MvtHa4lxXcgq4OWWw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4280 On 8/23/24 13:53, Jim Mattson wrote: > Prior to Zen4, AMD's IBPB did not flush the RAS (or, in Intel > terminology, the RSB). Hence, the older version of AMD's IBPB was not > equivalent to Intel's IBPB. However, KVM has been treating them as > equivalent, synthesizing Intel's CPUID.(EAX=7,ECX=0):EDX[bit 26] on any > platform that supports the synthetic features X86_FEATURE_IBPB and > X86_FEATURE_IBRS. > > Equivalence also requires a previously ignored feature on the AMD side, > CPUID Fn8000_0008_EBX[IBPB_RET], which is enumerated on Zen4. > > v3: Pass through IBPB_RET from hardware to userspace. [Tom] > Derive AMD_IBPB from X86_FEATURE_SPEC_CTRL rather than > X86_FEATURE_IBPB. [Tom] > Clarify semantics of X86_FEATURE_IBPB. > > v2: Use IBPB_RET to identify semantic equality. [Venkatesh] > > Jim Mattson (4): > x86/cpufeatures: Clarify semantics of X86_FEATURE_IBPB > x86/cpufeatures: Define X86_FEATURE_AMD_IBPB_RET > KVM: x86: Advertise AMD_IBPB_RET to userspace > KVM: x86: AMD's IBPB is not equivalent to Intel's IBPB > > arch/x86/include/asm/cpufeatures.h | 3 ++- > arch/x86/kvm/cpuid.c | 8 ++++++-- > 2 files changed, 8 insertions(+), 3 deletions(-) For the series: Reviewed-by: Tom Lendacky >