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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A5A7C7EE24 for ; Fri, 2 Jun 2023 16:22:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236517AbjFBQWv (ORCPT ); Fri, 2 Jun 2023 12:22:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236655AbjFBQWs (ORCPT ); Fri, 2 Jun 2023 12:22:48 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4836A197; Fri, 2 Jun 2023 09:22:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1685722952; x=1717258952; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=8SiuwRjOVa0SsobcOzLPmh2lj5ARFE5qrlu9m+PPYpo=; b=FFQ7HHjUI2VhRgMYdsHDooBDHU9nWaFGt3ECUCPiVotPsZ9TB/JnMETT 17gis2LcRA2JrB/yVU8djQJQMkWGcUqRmE4EqLN7P6RRBKVhESUuB2EsP /edM87RK+HgF9jkFHagL0Chm7F9WOYBozjD28BeN6LXBB56BghafYHbyd 9fGTonwu/F53IhPdbgfaA5r2DijuA3cz9A6iSJo8VIW5vLmqfQFYrX1l7 1HFlpiBIN4qSbxELYuRDJi4EO7Lj2Rm2WJgUlWtYBE4akdJxB+AjV8s1H 88Z7BXobeIL2Xzm2q6j7HLJEKfLbGm8j7LiT6/5+XKiv7F9IJdTDd68zT Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10729"; a="354759133" X-IronPort-AV: E=Sophos;i="6.00,213,1681196400"; d="scan'208";a="354759133" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jun 2023 09:21:55 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10729"; a="832034796" X-IronPort-AV: E=Sophos;i="6.00,213,1681196400"; d="scan'208";a="832034796" Received: from pingshi-mobl.amr.corp.intel.com (HELO [10.251.23.169]) ([10.251.23.169]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Jun 2023 09:21:47 -0700 Message-ID: <67a9a33c-1aa3-34ea-3e78-06301104773d@intel.com> Date: Fri, 2 Jun 2023 09:21:47 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH] x86/hyperv: add noop functions to x86_init mpparse functions Content-Language: en-US To: Wei Liu Cc: Saurabh Sengar , kys@microsoft.com, haiyangz@microsoft.com, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, mikelley@microsoft.com, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, hpa@zytor.com References: <1685709712-13752-1-git-send-email-ssengar@linux.microsoft.com> <442441b3-803e-0c1f-ff1b-5a49ecc2e423@intel.com> From: Dave Hansen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On 6/2/23 09:17, Wei Liu wrote: > On Fri, Jun 02, 2023 at 08:33:13AM -0700, Dave Hansen wrote: >> On 6/2/23 05:41, Saurabh Sengar wrote: >>> In !ACPI system, there is no way to disable CONFIG_X86_MPPARSE. >>> When CONFIG_X86_MPPARSE is enabled for VTL2, the kernel will >>> scan low memory looking for MP tables. Don't allow this, because >>> low memory is controlled by VTL0 and may contain actual valid >>> tables for VTL0, which can confuse the VTL2 kernel. >> Do you folks have a writeup of this VTL* setup anywhere? I'm struggling >> to grasp why VTL0 and VTL2 share the same address space and why they >> would get confused by each other's data structures. > Dave, here is some public information about Virtual Trust Level. > > https://learn.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/vsm#virtual-trust-level-vtl Yeah, I can google too. ;) Seriously, though. I don't need an architecture document. This is like me asking how NMIs work in Linux and someone pointing me to the SDM describing the hardware architecture. I need to know about the Linux implementation of these VTL's, not the overall VTL architecture.