Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753932Ab3J2Epy (ORCPT ); Tue, 29 Oct 2013 00:45:54 -0400 Received: from ch1ehsobe003.messaging.microsoft.com ([216.32.181.183]:1786 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751359Ab3J2Epw (ORCPT ); Tue, 29 Oct 2013 00:45:52 -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: -5 X-BigFish: VS-5(zz98dI9371I936eI542I1432I4015Izz1f42h208ch1ee6h1de0h1fdah2073h1202h1e76h1d1ah1d2ah1fc6hzz1de098h8275dh1de097hz2dh2a8h839h8e2h8e3h93fhd25hf0ah1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh15d0h162dh1631h1758h18e1h1946h19b5h1ad9h1b0ah1b2fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e1dh1fe8h1ff5h21a6h2216hbe9i1155h) From: Bhushan Bharat-R65777 To: Wood Scott-B07421 CC: 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 Thread-Topic: [PATCH 3/4] VFIO: pci: amend vfio-pci for explicit binding via sysfs only Thread-Index: AQHOxkr73mEL+MoRyUKqi8VAB5hpg5oKfwQAgAADdYCAAAK8AIAAngOwgAABegCAAADz8IAADMgAgAAAF9CAAAFhAIAAAQNg Date: Tue, 29 Oct 2013 04:45:46 +0000 Message-ID: <6A3DF150A5B70D4F9B66A25E3F7C888D071D4FE5@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> <1383020990.3410.76.camel@snotra.buserror.net> <6A3DF150A5B70D4F9B66A25E3F7C888D071D4FA0@039-SN2MPN1-013.039d.mgd.msft.net> <1383021306.3410.80.camel@snotra.buserror.net> In-Reply-To: <1383021306.3410.80.camel@snotra.buserror.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.232.14.2] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 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-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id r9T4k1wm009519 Content-Length: 7019 Lines: 166 > -----Original Message----- > From: Wood Scott-B07421 > Sent: Tuesday, October 29, 2013 10:05 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 23:31 -0500, Bhushan Bharat-R65777 wrote: > > > > > -----Original Message----- > > > From: Wood Scott-B07421 > > > Sent: Tuesday, October 29, 2013 10:00 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 22:52 -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? > > > > new_id interface to continue working as before. > > In what specific way does this allow new_id to continue working as before? Be > verbose. What I observed that this patch (kim's patch) new_id interface stops working. This is found to be because store_new_id() checks for pdrv->id_table which is no more NULL, so the below check fails if (ids) { ^^ This is no more NULL, so enter inside the loop 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; ^^^^^ This is where it returns as -EINVAL } I tried a quick test of what I am saying but it does not work directly (although passes from the above mentioned check), may be some more changes required :( -Bharat > > -Scott > ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?