From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47252) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y0VzX-000100-3X for qemu-devel@nongnu.org; Mon, 15 Dec 2014 08:47:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y0VzQ-0001HN-64 for qemu-devel@nongnu.org; Mon, 15 Dec 2014 08:47:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33371) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y0VzP-0001HH-UX for qemu-devel@nongnu.org; Mon, 15 Dec 2014 08:47:08 -0500 Message-ID: <548EE653.9020409@redhat.com> Date: Mon, 15 Dec 2014 14:46:59 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <5AD68BB8-35E0-4752-BD46-FA3CA9BC7F34@greensocs.com> <548EE2D4.6070603@redhat.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Atomic Instructions - comments please List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Mark Burton , Developers qemu-devel On 15/12/2014 14:39, Peter Maydell wrote: >> > >> > How would "add a mutex" work unless you add a mutex or CAS to each and >> > every qemu_st operation? > Same way our current approach works -- we simply don't implement > "stores interrupt ll/sc operations": only a store-conditional > can break a load-locked's lock. In practice this works ok > because the stereotypical sequences that guests use don't rely > on this part of the spec. Makes sense, thanks! Paolo