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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 0108DC433ED for ; Tue, 11 May 2021 16:04:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C004061919 for ; Tue, 11 May 2021 16:04:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231233AbhEKQF5 (ORCPT ); Tue, 11 May 2021 12:05:57 -0400 Received: from mga02.intel.com ([134.134.136.20]:22768 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229921AbhEKQF4 (ORCPT ); Tue, 11 May 2021 12:05:56 -0400 IronPort-SDR: lJgNnWvJaVyDw/UpdDj4LrcCkCtAf/3U3aPf7cF2MpXa0KV+22IEYgoKUukK7ki4cDIQ8bXiRF +G5UFLGEB9dA== X-IronPort-AV: E=McAfee;i="6200,9189,9981"; a="186614292" X-IronPort-AV: E=Sophos;i="5.82,291,1613462400"; d="scan'208";a="186614292" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2021 09:04:41 -0700 IronPort-SDR: DxcqpCR3rJHM1sp0RRZmHzIZq6qg3UZ8ePtdaXVAxvQY17mz5YLwmtSHYrurUoJ7G4aHj/QvIw 72Z/Rl5MKWLg== X-IronPort-AV: E=Sophos;i="5.82,291,1613462400"; d="scan'208";a="537084176" Received: from unknown (HELO [10.251.0.45]) ([10.251.0.45]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2021 09:04:40 -0700 Subject: Re: [RFC v2 16/32] x86/tdx: Handle MWAIT, MONITOR and WBINVD To: Andi Kleen , Dan Williams Cc: Kuppuswamy Sathyanarayanan , Peter Zijlstra , Andy Lutomirski , Tony Luck , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Raj Ashok , Sean Christopherson , Linux Kernel Mailing List References: <0e577692-101e-38f7-ebe2-2e7222016a9f@linux.intel.com> <43e0a5cc-721a-04f1-50b6-b1319da10bac@intel.com> <01b0e007-6af6-ca2e-2a0d-7ff4ca2a2927@linux.intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <01b0e007-6af6-ca2e-2a0d-7ff4ca2a2927@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/11/21 8:52 AM, Andi Kleen wrote: >> The 'default' case in this 'switch' prints the exit reason and faults, >> can't that also trigger a backtrace that dumps the exception stack and >> the faulting instruction? In other words shouldn't this just fail with >> a common way to provide better debug on any unhandled #VE and not try >> to continue running past something that "can't" happen? > > It will use the #GP common code which will do all the backtracing etc. > > We didn't think we would need anything else than what #GP already does. How do these end up in practice? Do they still say "general protection fault..."? Isn't that really mean for anyone that goes trying to figure out what caused these? If they see a "general protection fault" from WBINVD and go digging in the SDM for how a #GP can come from WBINVD, won't they be sorely disappointed?