From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KTHLb-0001uO-3h for qemu-devel@nongnu.org; Wed, 13 Aug 2008 10:29:11 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KTHLZ-0001ts-N8 for qemu-devel@nongnu.org; Wed, 13 Aug 2008 10:29:10 -0400 Received: from [199.232.76.173] (port=52180 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KTHLZ-0001tp-HQ for qemu-devel@nongnu.org; Wed, 13 Aug 2008 10:29:09 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:33662) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1KTHLZ-0002KX-Kg for qemu-devel@nongnu.org; Wed, 13 Aug 2008 10:29:09 -0400 Received: from samy by implementation.famille.thibault.fr with local (Exim 4.69) (envelope-from ) id 1KTHLZ-0003R3-Pa for qemu-devel@nongnu.org; Wed, 13 Aug 2008 16:29:09 +0200 Date: Wed, 13 Aug 2008 15:29:04 +0100 From: Samuel Thibault Subject: Re: [Qemu-devel] [PATCH] Flush pending AIO on reboot and shutdown. Message-ID: <20080813142904.GR6165@implementation.uk.xensource.com> References: <20080813132358.17672.68212.stgit@gleb-debian.qumranet.com.qumranet.com> <20080813134608.GN6165@implementation.uk.xensource.com> <20080813135941.GB17567@minantech.com> <20080813140641.GP6165@implementation.uk.xensource.com> <20080813142557.GD17567@minantech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20080813142557.GD17567@minantech.com> 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 Gleb Natapov, le Wed 13 Aug 2008 17:25:58 +0300, a écrit : > On Wed, Aug 13, 2008 at 03:06:41PM +0100, Samuel Thibault wrote: > > Gleb Natapov, le Wed 13 Aug 2008 16:59:41 +0300, a écrit : > > > On Wed, Aug 13, 2008 at 02:46:08PM +0100, Samuel Thibault wrote: > > > > Gleb Natapov, le Wed 13 Aug 2008 16:23:58 +0300, a écrit : > > > > > If there is outstanding IDE IO when BIOS starts execution then IDE > > > > > commands sent by BIOS will interfere with it and will leave IDE > > > > > subsystem in unpredictable state. This can happen when system reboots > > > > > unexpectedly without waiting for IO completion. Flushing IO before exit > > > > > prevents data lose. > > > > > > > > I'm wondering: isn't that what happens with real machines? > > > > > > > With shutdown yes, but why not try harder. With reboot I don't think > > > that in real HW you can hang IDE interface after reboot ;) > > > > Mmm, I couldn't understand. > > > > With real hardware, if you reboot into the bios the board is not > > resetted either, and thus the interference is the same. > > > On real hardware if you press reset button That's when you press the reset button. When you have a triple fault the IDE board won't be resetted. > Currently BOCHS BIOS doesn't check that IDE is busy (it doesn't even > know that HW is present) and sends overlapping command. Then fix it. Samuel