From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: [PATCH] xen/pci: make bus notifier handler return sane values Date: Thu, 25 Aug 2011 10:14:18 +0100 Message-ID: <1314263659.29585.7353.camel@elijah> References: <4E4B98C00200007800051A56@nat28.tlf.novell.com> <20110822162035.GA13410@dumpdata.com> <4E537E980200007800052B53@nat28.tlf.novell.com> <20110824204241.GC27865@dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110824204241.GC27865@dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Konrad Rzeszutek Wilk Cc: George Dunlap , Jeremy Fitzhardinge , "xen-devel@lists.xensource.com" , Jan Beulich List-Id: xen-devel@lists.xenproject.org On Wed, 2011-08-24 at 21:42 +0100, Konrad Rzeszutek Wilk wrote: > > Requiring the PCI device to be known to Xen to be able to use MSI is > > an implementation detail of the hypervisor. And in fact I had a patch > > to remove the call to pci_get_pdev() from map_domain_pirq() (since > > setup_msi_irq() doesn't really consume this parameter). This got made > > impossible to do (at least for the moment) with George's > > 23753:2e0cf9428554 (and later on the device is getting looked up by > > __pci_enable_msi{,x}() anyway, but even that is an implementation > > choice, not a hard requirement afaict). The device has to be known to Xen in order to do proper interrupt remapping, does it not? At least if the AMD per-device interrupt remapping tables. I suppose if you really wanted to, we could refactor the code so that the time Xen needed to know devices for IRQs coincided exactly with when Xen needs to know devices for IOMMUs. I don't understand the motivation for such a requirement yet. -George