From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752505AbcIIO1v (ORCPT ); Fri, 9 Sep 2016 10:27:51 -0400 Received: from smtp.citrix.com ([66.165.176.89]:51367 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750953AbcIIO1t (ORCPT ); Fri, 9 Sep 2016 10:27:49 -0400 X-IronPort-AV: E=Sophos;i="5.30,305,1470700800"; d="scan'208";a="377321802" Subject: Re: [Xen-devel] [PATCH v2] xen/pciback: support driver_override To: Juergen Gross , Boris Ostrovsky , , References: <1472819456-12995-1-git-send-email-jgross@suse.com> <74aef1d8-8f92-f7e4-fc40-a13708a2bf19@oracle.com> <69161c4e-02ac-5b02-8c9a-161d2ec2d6ce@suse.com> CC: From: David Vrabel Message-ID: <57D2C6DD.2050405@citrix.com> Date: Fri, 9 Sep 2016 15:27:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.5.0 MIME-Version: 1.0 In-Reply-To: <69161c4e-02ac-5b02-8c9a-161d2ec2d6ce@suse.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/09/16 07:14, Juergen Gross wrote: > On 08/09/16 16:10, Boris Ostrovsky wrote: >> On 09/02/2016 08:30 AM, Juergen Gross wrote: >>> Support the driver_override scheme introduced with commit 782a985d7af2 >>> ("PCI: Introduce new device binding path using pci_dev.driver_override") >>> >>> As pcistub_probe() is called for all devices (it has to check for a >>> match based on the slot address rather than device type) it has to >>> check for driver_override set to "pciback" itself. >>> >>> Signed-off-by: Juergen Gross >>> --- >>> V2: removed now unused label >>> --- >>> drivers/xen/xen-pciback/pci_stub.c | 16 ++++++++++------ >>> 1 file changed, 10 insertions(+), 6 deletions(-) >>> >>> diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c >>> index 258b7c3..85c28f7 100644 >>> --- a/drivers/xen/xen-pciback/pci_stub.c >>> +++ b/drivers/xen/xen-pciback/pci_stub.c >>> @@ -25,6 +25,8 @@ >>> #include "conf_space.h" >>> #include "conf_space_quirks.h" >>> >>> +#define PCISTUB_DRIVER_NAME "pciback" >>> + >>> static char *pci_devs_to_hide; >>> wait_queue_head_t xen_pcibk_aer_wait_queue; >>> /*Add sem for sync AER handling and xen_pcibk remove/reconfigue ops, >>> @@ -529,16 +531,18 @@ static int pcistub_probe(struct pci_dev *dev, const struct pci_device_id *id) >>> "don't have a normal (0) or bridge (1) " >>> "header type!\n"); >>> err = -ENODEV; >>> - goto out; >>> } >>> >>> + } else if (!dev->driver_override || >>> + strcmp(dev->driver_override, PCISTUB_DRIVER_NAME)) >>> + /* Didn't find the device */ >>> + err = -ENODEV; >>> + >>> + if (!err) { >>> dev_info(&dev->dev, "seizing device\n"); >>> err = pcistub_seize(dev); >>> - } else >>> - /* Didn't find the device */ >>> - err = -ENODEV; >>> + } >> >> Should devices with pciback override be displayed in >> /sys/bus/pci/drivers/pciback/slots? If they should then they need to be >> either added to pcistub_device_ids or kept on some other list. > > No, I don't think so. The patch is just needed to _avoid_ having to use > the slots stuff: without the patch you need something like: > > echo 0000:07:10.0 > /sys/bus/pci/devices/0000\:07\:10.0/driver/unbind > echo 0000:07:10.0 > /sys/bus/pci/drivers/pciback/new_slot > echo 0000:07:10.0 > /sys/bus/pci/drivers_probe > > while with the patch you can use the same mechanism as for similar > drivers like pci-stub and vfio-pci: > > echo pciback > /sys/bus/pci/devices/0000\:07\:10.0/driver_override > echo 0000:07:10.0 > /sys/bus/pci/devices/0000\:07\:10.0/driver/unbind > echo 0000:07:10.0 > /sys/bus/pci/drivers_probe > > So e.g. libvirt doesn't need special handling for pciback. The slot list > is necessary for assigning devices to pciback on boot, but I think the > override mechanism is better for runtime assignment. Can you include something like this in the commit message? David