From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46950) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fCnkq-0001ZL-85 for qemu-devel@nongnu.org; Sun, 29 Apr 2018 10:56:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fCnkn-00079Y-7C for qemu-devel@nongnu.org; Sun, 29 Apr 2018 10:56:44 -0400 Received: from mail-io0-x22d.google.com ([2607:f8b0:4001:c06::22d]:43186) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fCnkn-00079P-1f for qemu-devel@nongnu.org; Sun, 29 Apr 2018 10:56:41 -0400 Received: by mail-io0-x22d.google.com with SMTP id t23-v6so7598137ioc.10 for ; Sun, 29 Apr 2018 07:56:40 -0700 (PDT) References: <20180427210120.03d037b0@naga.suse.cz> From: Richard Henderson Message-ID: <70cb944b-269c-2969-4727-b889298ece30@linaro.org> Date: Sun, 29 Apr 2018 09:56:37 -0500 MIME-Version: 1.0 In-Reply-To: <20180427210120.03d037b0@naga.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] release retrospective, next release timing, numbering List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?Michal_Such=c3=a1nek?= , Peter Maydell Cc: Thomas Huth , QEMU Developers , Stefan Hajnoczi On 04/27/2018 02:01 PM, Michal Suchánek wrote: > Is there any reason why the 64bit emulator would not run on 32bit > system? The emulated 64bit system is .. emulated after all. It does run, but it requires that the 32-bit host perform double-word arithmetic to emulate the 64-bit guest. When the 64-bit guest is really a 32-bit guest in disguise, this carries a performance penalty. If we ever stop caring about 32-bit hosts, the question becomes moot. r~