From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:53724) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tkbwi-00065i-VN for qemu-devel@nongnu.org; Mon, 17 Dec 2012 09:45:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Tkbwe-0007S1-3M for qemu-devel@nongnu.org; Mon, 17 Dec 2012 09:45:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50380) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tkbwd-0007Rv-Rm for qemu-devel@nongnu.org; Mon, 17 Dec 2012 09:45:28 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id qBHEjRjg027686 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 17 Dec 2012 09:45:27 -0500 Message-ID: <50CF308C.70204@redhat.com> Date: Mon, 17 Dec 2012 15:47:40 +0100 From: Hans de Goede MIME-Version: 1.0 References: <1355492147-5023-1-git-send-email-hdegoede@redhat.com> <1355492147-5023-10-git-send-email-hdegoede@redhat.com> <50CF1B33.7060708@redhat.com> <50CF2AFB.2050705@redhat.com> <50CF2EB3.9020501@redhat.com> In-Reply-To: <50CF2EB3.9020501@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 09/26] ehci: Use uframe precision for interrupt threshold checking List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: qemu-devel@nongnu.org Hi, On 12/17/2012 03:39 PM, Gerd Hoffmann wrote: > On 12/17/12 15:23, Hans de Goede wrote: >> Hi, >> >> On 12/17/2012 02:16 PM, Gerd Hoffmann wrote: >>> On 12/14/12 14:35, Hans de Goede wrote: >>>> Note that a shadow variable is used instead of changing frindex to >>>> uframe accuracy because we must send a frindex which is a multiple of 8 >>>> during migration for migration compatibility, and rounding it down to >>>> a multiple of 8 pre-migration, can lead to frindex going backwards from >>>> the guest pov. >>> >>> Jumping forward instead? >> >> You mean rounding the send frindex up pre-migration, I didn't really >> consider >> that as it will cause us skipping processing an entry in the periodic frame >> list. I guess doing that on migration isn't too bad. OTOH giving the guest >> only frame accuracy like we've been doing till now also works fine... >> >> Your choice :) > > I'm looking for a way to avoid the shadow variable, but of course > without breaking migration. giving the guest only frame accuracy looks > good to me. Ok, but then we need the shadow variable, iow then the patch stays as is ... Regards, Hans