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=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 1299BC4743D for ; Sun, 6 Jun 2021 23:05:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF0C06142B for ; Sun, 6 Jun 2021 23:05:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230093AbhFFXHW (ORCPT ); Sun, 6 Jun 2021 19:07:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:37466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229723AbhFFXHV (ORCPT ); Sun, 6 Jun 2021 19:07:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E1BB361429; Sun, 6 Jun 2021 23:05:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623020731; bh=MP7FMA1pcXyauRBVKjd7g0X57/FdlVAQjI8PnSp5+IA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TPiDv2JP5SxK70TgvNXX1iEPgEIwTpgUXA8fVQoEnkUFqrMnDwUftADWfxiwRJ6ys Dpwy/xKEPiW88GjfqAU1rFfJKERpnoBAZNTL/wTuxS4Fg/RS9q/mTCfdhkeje7mwSx SeFSBqSLWqq24R4wEzYc2Xb/KyxkbLFt27DJ0WfjX1palvgW5u7I8TTpNmCzn59vC8 2QhJyDoyVcRphjlpSQaeDkwqx4vm9P29ngjFn4l+in2SN7f+xLWMexjJ0mM9t4DWgT PUiD8XefxZU9nmWTQzDI3R1I8nHuoCtZkV0PaoFiL99Tq4YfyV3cPNoM7gm4TZ1+0W Vkc5HfjZlcIuQ== Date: Sun, 6 Jun 2021 19:05:29 -0400 From: Sasha Levin To: Borislav Petkov Cc: Linus Torvalds , Mike Rapoport , x86-ml , lkml , James.Morris@microsoft.com Subject: Re: [GIT PULL] x86/urgent for v5.13-rc5 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 07, 2021 at 12:07:58AM +0200, Borislav Petkov wrote: >On Sun, Jun 06, 2021 at 02:23:21PM -0700, Linus Torvalds wrote: >> On Sun, Jun 6, 2021 at 1:58 PM Mike Rapoport wrote: >> > >> > A while ago hpa said: >> > >> > As far as I know, Windows 7 actually reserves all memory below >> > 1 MiB to avoid BIOS bugs. >> > >> > (https://bugzilla.kernel.org/show_bug.cgi?id=16661#c2) >> >> It would be good to have that checked somehow. >> >> I don't think this matters on any machine with gigs of RAM, but I do >> wonder about the people who want to do small configurations. Maybe >> they've given up on x86? >> >> It also eats into that somewhat precious legacy DMA resource and eats >> up a fair chunk of that. Again, not an issue on modern hardware, but >> .. >> >> > I believe that reserving everything below 1M after the real mode trampoline >> > is allocated reduces amount of hidden dependencies and makes things simpler >> > overall. >> >> Simpler, perhaps, and _I_ personally don't care about about 512kB of >> memory any more on any machines I have, but .. > >Let's see if Sasha can dig out something... CCed. > >@Sasha, can you figure out who we can talk to whether Windoze reserves >the first megabyte of memory unconditionally? That's a great question, but I can't help there anymore :) Adding James Morris... -- Thanks, Sasha