From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: KVM_ASSIGN_SET_MSIX_NR and KVM_ASSIGN_SET_MSIX_ENTRY should support MSI? Date: Tue, 5 May 2009 15:01:34 +0300 Message-ID: <20090505120134.GE15418@redhat.com> References: <20090505103028.GA15418@redhat.com> <20090505110415.GA4114@amt.cnet> <20090505110815.GC15418@redhat.com> <4A002996.6040803@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Marcelo Tosatti , Sheng Yang , Matthew Wilcox , kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx2.redhat.com ([66.187.237.31]:41807 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751908AbZEEMCe (ORCPT ); Tue, 5 May 2009 08:02:34 -0400 Content-Disposition: inline In-Reply-To: <4A002996.6040803@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, May 05, 2009 at 02:57:10PM +0300, Avi Kivity wrote: > Michael S. Tsirkin wrote: >> On Tue, May 05, 2009 at 08:04:15AM -0300, Marcelo Tosatti wrote: >> >>> On Tue, May 05, 2009 at 01:30:28PM +0300, Michael S. Tsirkin wrote: >>> >>>> The new KVM_ASSIGN_SET_MSIX_NR and KVM_ASSIGN_SET_MSIX_ENTRY ioctls have >>>> been merged for 2.6.30. However, I note that PCI spec allows devices to >>>> support multiple vectors with MSI as well (support will be in linux >>>> 2.6.30). >>>> >>>> Even though qemu for now only uses a single vector with MSI, it would >>>> seem that it's better to make the kernel/user interface generic straight >>>> away rather than add more ioctls later. What do you think? It might not >>>> be too late to fix this for 2.6.30. >>>> >>> Can't you use more than one KVM_ASSIGN_SET_MSIX_ENTRY call per assigned >>> device? >>> >> >> Sure, but only one KVM_ASSIGN_SET_MSIX_NR. >> >> > > MSIX_NR is the size of the table, while MSIX_ENTRY updates a single > entry, if I read the code correctly. Right. So we'll need something like this for MSI as well. Actually maybe MSIX_NR MSIX_ENTRY should be renamed to MSI_NR / MSI_ENTRY and changed to do the right thing depending on the IRQ type? -- MST