From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=46168 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Q1dwW-0004rZ-IL for qemu-devel@nongnu.org; Mon, 21 Mar 2011 08:10:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Q1dwT-00032U-Ex for qemu-devel@nongnu.org; Mon, 21 Mar 2011 08:10:38 -0400 Received: from mail.valinux.co.jp ([210.128.90.3]:43120) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q1dwT-00031T-1Q for qemu-devel@nongnu.org; Mon, 21 Mar 2011 08:10:37 -0400 Date: Mon, 21 Mar 2011 21:10:32 +0900 From: Isaku Yamahata Message-ID: <20110321121032.GA9998@valinux.co.jp> References: <533593a679f7c243ddce87c9c3a7c31c6f67acd7.1300540833.git.yamahata@valinux.co.jp> <20110321113707.GC27445@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110321113707.GC27445@redhat.com> Subject: [Qemu-devel] Re: [PATCH v3 3/3] piix_pci: optimize set irq path List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org On Mon, Mar 21, 2011 at 01:37:07PM +0200, Michael S. Tsirkin wrote: > > +static int piix3_post_load(void *opaque, int version_id) > > +{ > > + PIIX3State *piix3 = opaque; > > + piix3_update_irq_levels(piix3); > > Couldn't figure out why would we not want to > propagate the interrupts here. > Could you explain please? > What happens if we do propagate them? > Nothing bad, right? I wanted to be just conservative. If you are brave enough to change the behavior, I'm fine with propagating interrupts. If we propagate the interrupts, guest OS may see interrupts unnecessarily/spuriously injected after load. Probably such interrupts doesn't harm OSes, so there is nothing bad in theory as you said. On the other hand, I hesitated to change the existing behavior because it would be very difficult to debug it and to test many OSes. -- yamahata