From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 5/7] qemu-kvm: Move gsi bits from kvm_msix_vector_add to kvm_msi_add_message Date: Wed, 27 Apr 2011 16:36:00 +0300 Message-ID: <20110427133600.GI15788@redhat.com> References: <20110427125411.GF15788@redhat.com> <4DB81A2B.9020603@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , Marcelo Tosatti , kvm@vger.kernel.org To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:16992 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932378Ab1D0NgO (ORCPT ); Wed, 27 Apr 2011 09:36:14 -0400 Content-Disposition: inline In-Reply-To: <4DB81A2B.9020603@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Apr 27, 2011 at 03:29:15PM +0200, Jan Kiszka wrote: > On 2011-04-27 14:54, Michael S. Tsirkin wrote: > > On Sat, Apr 23, 2011 at 12:23:38PM +0200, Jan Kiszka wrote: > >> From: Jan Kiszka > >> > >> Testing support and allocating a GSI for an MSI message is required both > >> for MSI and MSI-X. At this chance, drop the aging version warning. > >> > >> Signed-off-by: Jan Kiszka > > > > No objection, but I do note that this means running on an old > > kernel will lead to a silent failure. > > Shouldn't be silent: The caller of msi_vector_use should check and > process the error (virtio should even forward it to guest IIUC). It does, but the msi/msix spec does not allow this so not all guest OSes can use this extended reporting. > > stderr output is not in fact much better: I think we should > > check the capability in msix_init. Care coding this up? > > I think the motivation to check on vector activation is that devices and > guests without a need for MSI should not cause a failure if MSI is > unsupported by KVM. > > Jan IMO it's better not to report MSI capability in this setup. > -- > Siemens AG, Corporate Technology, CT T DE IT 1 > Corporate Competence Center Embedded Linux