Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753581Ab3J2E36 (ORCPT ); Tue, 29 Oct 2013 00:29:58 -0400 Received: from co1ehsobe005.messaging.microsoft.com ([216.32.180.188]:33043 "EHLO co1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751862Ab3J2E35 (ORCPT ); Tue, 29 Oct 2013 00:29:57 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: -6 X-BigFish: VS-6(zz98dI9371I936eI542I1432I4015Izz1f42h208ch1ee6h1de0h1fdah2073h1202h1e76h1d1ah1d2ah1fc6hzz1de098h8275dh1de097hz2dh2a8h839h93fhd24hf0ah1288h12a5h12a9h12bdh137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e23h1fe8h1ff5h2218h2216h1155h) Message-ID: <1383020990.3410.76.camel@snotra.buserror.net> Subject: Re: [PATCH 3/4] VFIO: pci: amend vfio-pci for explicit binding via sysfs only From: Scott Wood To: Bhushan Bharat-R65777 CC: Wood Scott-B07421 , Alex Williamson , Kim Phillips , Yoder Stuart-B08248 , "christoffer.dall@linaro.org" , "linux-kernel@vger.kernel.org" , "a.motakis@virtualopensystems.com" , "agraf@suse.de" , Sethi Varun-B16395 , "peter.maydell@linaro.org" , "santosh.shukla@linaro.org" , "kvm@vger.kernel.org" , "gregkh@linuxfoundation.org" Date: Mon, 28 Oct 2013 23:29:50 -0500 In-Reply-To: <6A3DF150A5B70D4F9B66A25E3F7C888D071D4F3A@039-SN2MPN1-013.039d.mgd.msft.net> References: <1381418830.7979.405.camel@snotra.buserror.net> <1381472840-3470-1-git-send-email-kim.phillips@linaro.org> <1381472840-3470-3-git-send-email-kim.phillips@linaro.org> <1382982462.4097.38.camel@ul30vt.home> <1382983205.3410.6.camel@snotra.buserror.net> <1382983792.3410.13.camel@snotra.buserror.net> <6A3DF150A5B70D4F9B66A25E3F7C888D071D4F0B@039-SN2MPN1-013.039d.mgd.msft.net> <1383018042.3410.69.camel@snotra.buserror.net> <6A3DF150A5B70D4F9B66A25E3F7C888D071D4F3A@039-SN2MPN1-013.039d.mgd.msft.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4207 Lines: 98 On Mon, 2013-10-28 at 22:52 -0500, Bhushan Bharat-R65777 wrote: > > > -----Original Message----- > > From: Wood Scott-B07421 > > Sent: Tuesday, October 29, 2013 9:11 AM > > To: Bhushan Bharat-R65777 > > Cc: Wood Scott-B07421; Alex Williamson; Kim Phillips; Yoder Stuart-B08248; > > christoffer.dall@linaro.org; linux-kernel@vger.kernel.org; > > a.motakis@virtualopensystems.com; agraf@suse.de; Sethi Varun-B16395; > > peter.maydell@linaro.org; santosh.shukla@linaro.org; kvm@vger.kernel.org; > > gregkh@linuxfoundation.org > > Subject: Re: [PATCH 3/4] VFIO: pci: amend vfio-pci for explicit binding via > > sysfs only > > > > On Mon, 2013-10-28 at 22:38 -0500, Bhushan Bharat-R65777 wrote: > > > > > > > -----Original Message----- > > > > From: Wood Scott-B07421 > > > > Sent: Monday, October 28, 2013 11:40 PM > > > > To: Alex Williamson > > > > Cc: Kim Phillips; Bhushan Bharat-R65777; Wood Scott-B07421; Yoder > > > > Stuart-B08248; christoffer.dall@linaro.org; > > > > linux-kernel@vger.kernel.org; a.motakis@virtualopensystems.com; > > > > agraf@suse.de; Sethi Varun-B16395; peter.maydell@linaro.org; > > > > santosh.shukla@linaro.org; kvm@vger.kernel.org; > > > > gregkh@linuxfoundation.org > > > > Subject: Re: [PATCH 3/4] VFIO: pci: amend vfio-pci for explicit > > > > binding via sysfs only > > > > > > > > On Mon, 2013-10-28 at 13:00 -0500, Scott Wood wrote: > > > > > On Mon, 2013-10-28 at 11:47 -0600, Alex Williamson wrote: > > > > > > On Fri, 2013-10-11 at 01:27 -0500, Kim Phillips wrote: > > > > > > > Force the vfio-pci driver to only be bound explicitly via > > > > > > > sysfs to avoid conflics with other drivers in the event of a hotplug. > > > > > > > > > > > > We can't break userspace, so we can't disable the current method > > > > > > of binding devices to vfio-pci. We can add a new method and > > > > > > perhaps deprecate the existing mechanism to be removed at some > > > > > > point in the future. Thanks, > > > > > > > > > > I thought the existing method involved using sysfs bind, and this > > > > > was just eliminating a race. How does the bind get triggered currently? > > > > > > > > OK, so it seems it's relying on the write to new_id calling driver_attach(). > > > > Sigh. I guess we could make driver-sysfs-bind-only be settable via > > > > sysfs, and have new-userspace set both that and PCI_ANY_ID (or the > > > > specific ID if userspace > > > > prefers) via new_id. The platform bus patches could continue as is, > > > > since there's no existing mechanism to break. > > > > > > What about changing the store_new_id() to bypass exact ids check if driver > > have PCI_ANY_ID? > > > > I don't follow. > > store_new_id() function id defined as: > > static ssize_t store_new_id(struct device_driver *driver, const char *buf, size_t count) > { > struct pci_driver *pdrv = to_pci_driver(driver); > const struct pci_device_id *ids = pdrv->id_table; > > > /* Only accept driver_data values that match an existing id_table > entry */ > if (ids) { > retval = -EINVAL; > while (ids->vendor || ids->subvendor || ids->class_mask) { > if (driver_data == ids->driver_data) { > retval = 0; > break; > } > ids++; > } > if (retval) /* No match */ > return retval; > } > > retval = pci_add_dynid(pdrv, vendor, device, subvendor, subdevice, > class, class_mask, driver_data); > > > > So when ids == NULL it does not check of vendor etc and calls pci_add_dynid() which in turn calls driver_attach(). > > If we change the above loop to break if ids->vendor == PCI_ANY_ID && ids->subvendor == PCI_ANY_ID then also we will call pci_add_dyids(). What problem are you trying to solve? -Scott -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/