Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753258AbdI1Nqb (ORCPT ); Thu, 28 Sep 2017 09:46:31 -0400 Received: from twosheds.infradead.org ([90.155.92.209]:44128 "EHLO twosheds.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753053AbdI1Nq1 (ORCPT ); Thu, 28 Sep 2017 09:46:27 -0400 Message-ID: <1506606369.7476.96.camel@infradead.org> Subject: Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support From: David Woodhouse To: Don Dutile , Alexander Duyck Cc: Bjorn Helgaas , Greg Kroah-Hartman , linux-pci , linux-kernel , Alexander Duyck , "Bryant G. Ly" , Bodong Wang , Alex Williamson , "Michael S. Tsirkin" , kvm@vger.kernel.org In-Reply-To: References: <1506517162.30379.2.camel@infradead.org> <20170927220005.GB23674@bhelgaas-glaptop.roam.corp.google.com> <1506550852.7476.33.camel@infradead.org> Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwBAMAAAClLOS0AAAAG1BMVEUHBwcUFBQpKSlGRkZhYWF9fX2Xl5eysrLMzMxFF+rXAAACaElEQVQ4y21UQXbbIBQE9wJALmAg6ToWON22FrhZthHgbvssUPathC7QWMful2JHSmtWwGg+zPxBCE0DU4QoJQgRgsg4w2gJjBNE8PjFBZgnQMBs+uZ1NQNQjZO3BV4AGDFC0f+l4DBG0VUAM4yv7SO8IgRdHXQ+A78HKL5OAeCfNQV5cHX8DsBUyIJKtYbt98BKaGNCKjfgFVkqYVLbkHKsRsbSCSa0T6npIqLrpRBgQKHUpQmgs9eEKaiUcooE8WWfCGVnBiUcn1uF2XhbfmN9apKnmMP2K4kizKkQWxuaVNOpU2cACIyxO1Po8ETHcXEDMVnozcejkAYA9iaD4pU0ZvNQ8VurNnTuFAYVtuIPUZW25PjDIjQAlGyffIiRQxoWAZBmJ0LTdW2Nyc0iP3DqRhxizvGJkBWZmyFVyZkddWzmBoIBVMpCCJ1CFzl98xav4VJKSSD45KbUT75ixikTphDSRh8+Uz7JLgUTAgAFwzqzjxc/nDY7WUApqY0OMdTwCKZSXplSKkgIRCHElCp8ZnhnKqXuwcNbk1L0VXE+I9alUXoHlLHl3mv7/dWQlJwtjREC7mu9L/U2jQyMUuO2EDS4q9Kl2ddm232bxIE5pjJuVwiljNn/Cfv25/T0cu5cZbwHGVq7h/zp0B4n3S99V/utD+Uo8BiGx9xCsOAV5z7/tjo4Z4z1Lvb90KZ7eFOoOeXOukqF2seo234YYuaQPpRP+cVZU5adT1Edun5Iz3z8fTz3+eSDh0Ip1c7zx1MaijGzTd/3MbRuBHz8cvcVgCMBRpOHvgu59WDhoat+nIZm+LWm9C/aaaGq5DCP9QAAAABJRU5ErkJggg== Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-IwkJPS/M/7xgCMiXW9oG" Date: Thu, 28 Sep 2017 14:46:09 +0100 Mime-Version: 1.0 X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 X-SRS-Rewrite: SMTP reverse-path rewritten from by twosheds.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8229 Lines: 129 --=-IwkJPS/M/7xgCMiXW9oG Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2017-09-28 at 08:22 -0400, Don Dutile wrote: >=20 > After reading Alex's response, I now understand Dave's question > better and why the patch won't work in general. UIO doesn't work "in general". It requires a very *specific* userspace driver for the hardware in question, which needs to know what it's doing. > In every SRIOV capable device I've run into to date, the PF has > to know the VFs are being assigned due to some resource mgmt, if not > internal (e.g., switch) configuration reasons. > The reasons are often subtle. Sure. If there's actually a userspace driver (which in my case there isn't), and if that's needed for the hardware ins question (which in my case it isn't), then it'd need to do that before enabling the VFs via the user-level sysfs interface of which you speak. > =C2=A0From the context of the patches (uio), why aren't VFs enabled via > user-level sysfs interface? That was provided for user-mgmt apps > to have a PCIe-generic/common, device-independent method of VF > enablement=20 That is *precisely* what we're doing. But the user-space sysfs interface doesn't actually *exist* unless a driver is bound to the device in question, with a .sriov-configure method. Which is where I came in... :) --=-IwkJPS/M/7xgCMiXW9oG Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCDzUw ggSvMIIDl6ADAgECAhEA4CPLFRKDU4mtYW56VGdrITANBgkqhkiG9w0BAQsFADBvMQswCQYDVQQG EwJTRTEUMBIGA1UEChMLQWRkVHJ1c3QgQUIxJjAkBgNVBAsTHUFkZFRydXN0IEV4dGVybmFsIFRU UCBOZXR3b3JrMSIwIAYDVQQDExlBZGRUcnVzdCBFeHRlcm5hbCBDQSBSb290MB4XDTE0MTIyMjAw MDAwMFoXDTIwMDUzMDEwNDgzOFowgZsxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVhdGVyIE1h bmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVkMUEw PwYDVQQDEzhDT01PRE8gU0hBLTI1NiBDbGllbnQgQXV0aGVudGljYXRpb24gYW5kIFNlY3VyZSBF bWFpbCBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAImxDdp6UxlOcFIdvFamBia3 uEngludRq/HwWhNJFaO0jBtgvHpRQqd5jKQi3xdhTpHVdiMKFNNKAn+2HQmAbqUEPdm6uxb+oYep LkNSQxZ8rzJQyKZPWukI2M+TJZx7iOgwZOak+FaA/SokFDMXmaxE5WmLo0YGS8Iz1OlAnwawsayT 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