From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56364) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bEyoF-00041s-4v for qemu-devel@nongnu.org; Mon, 20 Jun 2016 09:00:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bEyo9-0000Yu-4Z for qemu-devel@nongnu.org; Mon, 20 Jun 2016 09:00:10 -0400 Received: from mail-wm0-x242.google.com ([2a00:1450:400c:c09::242]:35884) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bEyo8-0000Ya-Td for qemu-devel@nongnu.org; Mon, 20 Jun 2016 09:00:05 -0400 Received: by mail-wm0-x242.google.com with SMTP id c82so10966993wme.3 for ; Mon, 20 Jun 2016 06:00:04 -0700 (PDT) Sender: Paolo Bonzini References: <1466151257-96318-1-git-send-email-chao.p.peng@linux.intel.com> <20160620060129.GE21465@pengc-linux.bj.intel.com> <76b78e27-c14f-ebb5-baab-a0bf75a60a10@redhat.com> <20160620123125.GH14100@stefanha-x1.localdomain> From: Paolo Bonzini Message-ID: Date: Mon, 20 Jun 2016 15:00:01 +0200 MIME-Version: 1.0 In-Reply-To: <20160620123125.GH14100@stefanha-x1.localdomain> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [RFC 0/9] Introduce light weight PC platform pc-lite List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Chao Peng , Haozhong Zhang , Xiao Guangrong , Eduardo Habkost , "Michael S. Tsirkin" , qemu-devel@nongnu.org, anthony.xu@intel.com, gor Mammedov , Richard Henderson On 20/06/2016 14:31, Stefan Hajnoczi wrote: > On Mon, Jun 20, 2016 at 08:54:10AM +0200, Paolo Bonzini wrote: > > I wonder if Linux could run as a multiboot-compliant ELF file, and what > > the performance would be... Multiboot omits the real mode stub. > > The Linux boot protocol does not require real mode. I think "64-bit > BOOT PROTOCOL" in Documentation/x86/boot.txt could be used. Yes, the real mode is only needed to decompress the kernel, to retrieve the e820 memory map, and then invoke the Linux boot protocol. However, neither QEMU nor (I think) GRUB can boot a vmlinux file. So I wondered if it would be possible to compile Linux in a format that is not compressed (for speed) and can be invoked by both QEMU and GRUB. Multiboot seems interesting because it has other advantages. For example it supports modules, so you can use it with an initrd, and it passes the e820 data directly to the loaded kernel. Paolo