From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH] Inform users about busy device assignment attempt Date: Wed, 09 Dec 2009 20:44:06 +0100 Message-ID: <4B1FFE06.8090909@suse.de> References: <1260381853-8954-1-git-send-email-agraf@suse.de> <20091209181956.GA13487@redhat.com> <4B1FF7FD.5080407@suse.de> <20091209194030.GD13487@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: "Daniel P. Berrange" Return-path: Received: from cantor.suse.de ([195.135.220.2]:39237 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751043AbZLIToA (ORCPT ); Wed, 9 Dec 2009 14:44:00 -0500 In-Reply-To: <20091209194030.GD13487@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Daniel P. Berrange wrote: > On Wed, Dec 09, 2009 at 08:18:21PM +0100, Alexander Graf wrote: > >> Daniel P. Berrange wrote: >> >>> Unconditionally telling people to run rmmod is a pretty dangerous thing >>> todo. If they typod and gave the PCI addr of their disk controller instead >>> of the NIC, they'll be less than happy at the results of our recommended >>> command to "fix" the error. Likewise if they have multiple devices using >>> the same driver & just want to assign one of them. I think it is safer to >>> just have the first bit of your proposed error message >>> >>> "The device 04:00.0 is in use by the kernel driver 'igb'." >>> >>> >>> NB 'rmmod' is not the ideal approach for PCI assignment. It is better >>> to explicitly re-bind the device to 'pcistub' because that ensures that >>> no other driver will ever be able to reclaim the device. >>> >>> >> Oh - mind to get into detail there? It'd be great if we could tell users >> an even better way to unbind their device from the driver than rmmod :) >> > > The direct low level sysfs way involves the following steps > > // Tell pci-stub to accept a particular vendor+product ID binding > # echo "8086 27cb" > /sys/bus/pci/drivers/pci-stub/new_id > > // Remove device from existing PCI driver > # echo "00:1d.3" > /sys/bus/pci/drivers/e1000/unbind > > // Add device to pci-stub PCI driver > # echo "00:1d.3" > /sys/bus/pci/drivers/pci-stub/bind > > // Tell pci-stub to stop accepting a vendor+product ID binding > # echo "8086 27cb" > /sys/bus/pci/drivers/pci-stub/remove_id > > The reason for that last step is that if you have multiple devices of > the same vendor+product, you don't want a later hotplug event to bind > the new device to pci-stub too ! > So what would you think if we'd just print out those 4 commands to the user, so people who don't use libvirt still get guidance when using -pcidevice :). They should be fairly easy to construct from the information we have. Alex