From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id D0BFB6B0005 for ; Mon, 29 Jan 2018 06:59:37 -0500 (EST) Received: by mail-pf0-f199.google.com with SMTP id m65so6667088pfm.14 for ; Mon, 29 Jan 2018 03:59:37 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id e3si1021965pfi.191.2018.01.29.03.59.35 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 29 Jan 2018 03:59:35 -0800 (PST) Date: Mon, 29 Jan 2018 03:59:27 -0800 From: Matthew Wilcox Subject: Re: [PATCH] x86/kexec: Make kexec work in 5-level paging mode Message-ID: <20180129115927.GB18247@bombadil.infradead.org> References: <20180129110845.26633-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180129110845.26633-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Ingo Molnar , x86@kernel.org, Thomas Gleixner , "H. Peter Anvin" , Borislav Petkov , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon, Jan 29, 2018 at 02:08:45PM +0300, Kirill A. Shutemov wrote: > I've missed that we need to change relocate_kernel() to set CR4.LA57 > flag if the kernel has 5-level paging enabled. > > I avoided to use ifdef CONFIG_X86_5LEVEL here and inferred if we need to > enabled 5-level paging from previous CR4 value. This way the code is > ready for boot-time switching between paging modes. Forgive me if I'm missing something ... can you kexec a 5-level kernel from a 4-level kernel or vice versa? -- 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