From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 442CF6B0038 for ; Tue, 24 Oct 2017 07:35:17 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id g75so18365458pfg.4 for ; Tue, 24 Oct 2017 04:35:17 -0700 (PDT) Received: from mail.zytor.com (terminus.zytor.com. [65.50.211.136]) by mx.google.com with ESMTPS id g3si53761plb.50.2017.10.24.04.35.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Oct 2017 04:35:15 -0700 (PDT) Date: Tue, 24 Oct 2017 13:32:51 +0200 In-Reply-To: <20171017154241.f4zaxakfl7fcrdz5@node.shutemov.name> References: <20170929140821.37654-1-kirill.shutemov@linux.intel.com> <20171003082754.no6ym45oirah53zp@node.shutemov.name> <20171017154241.f4zaxakfl7fcrdz5@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH 0/6] Boot-time switching between 4- and 5-level paging for 4.15, Part 1 From: hpa@zytor.com Message-ID: Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" , Ingo Molnar Cc: "Kirill A. Shutemov" , Linus Torvalds , x86@kernel.org, Thomas Gleixner , Andrew Morton , Andy Lutomirski , Cyrill Gorcunov , Borislav Petkov , linux-mm@kvack.org, linux-kernel@vger.kernel.org On October 17, 2017 5:42:41 PM GMT+02:00, "Kirill A=2E Shutemov" wrote: >On Tue, Oct 03, 2017 at 11:27:54AM +0300, Kirill A=2E Shutemov wrote: >> On Fri, Sep 29, 2017 at 05:08:15PM +0300, Kirill A=2E Shutemov wrote: >> > The first bunch of patches that prepare kernel to boot-time >switching >> > between paging modes=2E >> >=20 >> > Please review and consider applying=2E >>=20 >> Ping? > >Ingo, is there anything I can do to get review easier for you? > >I hoped to get boot-time switching code into v4=2E15=2E=2E=2E One issue that has come up with this is what happens if the kernel is load= ed above 4 GB and we need to switch page table mode=2E In that case we nee= d enough memory below the 4 GB point to hold a root page table (since we ca= n't write the upper half of cr3 outside of 64-bit mode) and a handful of in= structions=2E We have no real way to know for sure what memory is safe without parsing a= ll the memory maps and map out all the data structures that The bootloader = has left for the kernel=2E I'm thinking that the best way to deal with thi= s is to add an entry in setup_data to provide a pointers, with the kernel h= eader specifying a necessary size and alignment=2E --=20 Sent from my Android device with K-9 Mail=2E Please excuse my brevity=2E -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org