From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/1] kvm: qemu: Add VIRTIO_F_NOTIFY_ON_EMPTY Date: Wed, 18 Jun 2008 06:31:48 -0700 Message-ID: <48590E44.2030202@qumranet.com> References: <1213362983-17025-1-git-send-email-markmc@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm-devel To: Mark McLoughlin Return-path: Received: from il.qumranet.com ([212.179.150.194]:31999 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752419AbYFRNbv (ORCPT ); Wed, 18 Jun 2008 09:31:51 -0400 In-Reply-To: <1213362983-17025-1-git-send-email-markmc@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Mark McLoughlin wrote: > Set the VIRTIO_F_NOTIFY_ON_EMPTY feature bit so the > guest can rely on us notifying them when the queue > is empty. > > Also, only notify when the available queue is empty > *and* when we've finished with all the buffers we > had detached. Right now, when the queue is empty, > we notify the guest for every used buffer. > This is a bit inflexible. I would prefer a mechanism where the guest tells us at what queue index it would like the notification, like Xen. If it wants it on queue empty, it just sets the index appropriately. Or is the usage in the drivers already upstream and I have no choice about applying this? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.