From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1L0p6d-0000R2-Ku for qemu-devel@nongnu.org; Thu, 13 Nov 2008 22:12:23 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1L0p6a-0000Py-SR for qemu-devel@nongnu.org; Thu, 13 Nov 2008 22:12:23 -0500 Received: from [199.232.76.173] (port=39621 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1L0p6a-0000Pp-Ky for qemu-devel@nongnu.org; Thu, 13 Nov 2008 22:12:20 -0500 Received: from mail2.shareable.org ([80.68.89.115]:36821) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1L0p6a-0003sN-9I for qemu-devel@nongnu.org; Thu, 13 Nov 2008 22:12:20 -0500 Received: from jamie by mail2.shareable.org with local (Exim 4.63) (envelope-from ) id 1L0p6Y-00014k-MX for qemu-devel@nongnu.org; Fri, 14 Nov 2008 03:12:18 +0000 Date: Fri, 14 Nov 2008 03:12:18 +0000 From: Jamie Lokier Subject: Re: [Qemu-devel] [PATCH 1/2] Add HPET emulation to qemu (v4) Message-ID: <20081114031218.GI2055@shareable.org> References: <1226613844.1157.43.camel@beth-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1226613844.1157.43.camel@beth-laptop> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Beth Kon wrote: > - enabled 64-bit capability (after discovering that OS is > warned in HPET spec about possibility that a 64-bit read may > be implemented as two 32-bit reads). It's in the spec, but are there any real x86_64 machines where 64-bit HPET read would be translated into two 32-bit reads? I'm wondering if some OSes ssume reading HPET with a 64-bit read on x86_64 is atomic, because that might be true. Linux seems to use HPET in 32-bit mode so that's safe (I checked Linux 2.6.26). -- Jamie