From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752351AbdBOQ5c (ORCPT ); Wed, 15 Feb 2017 11:57:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53772 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752287AbdBOQ5R (ORCPT ); Wed, 15 Feb 2017 11:57:17 -0500 Date: Wed, 15 Feb 2017 09:57:11 -0700 From: Alex Williamson To: Manish Jaggi Cc: bhelgaas@google.com, linux-pci@vger.kernel.org, Tirumalesh Chalamarla , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Revert: "PCI: Add ACS quirk for all Cavium devices" Message-ID: <20170215095711.206ea8d5@t450s.home> In-Reply-To: <4ce1e1e6-1f5f-67eb-6615-00a21acbe285@caviumnetworks.com> References: <20170214161711.21753.16746.stgit@gimli.home> <20170215093449.5e6f4ab3@t450s.home> <4ce1e1e6-1f5f-67eb-6615-00a21acbe285@caviumnetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 15 Feb 2017 16:57:12 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 15 Feb 2017 22:12:54 +0530 Manish Jaggi wrote: > Hi Alex, > > On 2/15/2017 10:04 PM, Alex Williamson wrote: > > On Tue, 14 Feb 2017 09:18:18 -0700 > > Alex Williamson wrote: > > > >> This reverts commit b404bcfbf035413dcce539c8ba2c9986d220d8ed. > >> > >> The reverted commit makes no attempt to selectively consider devices, > >> current or future. Instead, it whitelists the entire PCI vendor ID. > >> This is a reckless approach as we clearly cannot know whether future > >> device IDs within this vendor ID are susceptible to peer-to-peer. > >> Additionally, the comment suggests this quirk is only relevant to > >> ThunderX, which raises further doubt whether it is appropriate to > >> apply to the entire vendor ID. > >> > >> Signed-off-by: Alex Williamson > >> Cc: Manish Jaggi > >> Cc: Tirumalesh Chalamarla > >> --- > >> > >> Please submit a new quirk targeting specific devices > > Sorry, I saw the date on the original commit as January 30, 2016 and > > forgot we're now in 2017, so I figured that this had only recently gone > > in. Since it's actually been around since 4.6, I'll take a different > > approach. Instead of reverting, I'm going to assume that this applies > > to ThunderX devices as per the comment. I'll follow-up with a new > > patch that only applies this to device IDs matching ThunderX as found > > here http://pci-ids.ucw.cz/read/PC/177d Perhaps in the meantime, > > someone from Cavium will comment on which subset of those devices this > > is actually relevant to. > I will provide another patch with the specific device Ids. Perfect, thank you Manish. Alex > >> drivers/pci/quirks.c | 15 --------------- > >> 1 file changed, 15 deletions(-) > >> > >> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > >> index 1800befa8b8b..449eabb438e2 100644 > >> --- a/drivers/pci/quirks.c > >> +++ b/drivers/pci/quirks.c > >> @@ -4060,19 +4060,6 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags) > >> #endif > >> } > >> > >> -static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags) > >> -{ > >> - /* > >> - * Cavium devices matching this quirk do not perform peer-to-peer > >> - * with other functions, allowing masking out these bits as if they > >> - * were unimplemented in the ACS capability. > >> - */ > >> - acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR | > >> - PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT); > >> - > >> - return acs_flags ? 0 : 1; > >> -} > >> - > >> /* > >> * Many Intel PCH root ports do provide ACS-like features to disable peer > >> * transactions and validate bus numbers in requests, but do not provide an > >> @@ -4276,8 +4263,6 @@ static int pci_quirk_mf_endpoint_acs(struct pci_dev *dev, u16 acs_flags) > >> { PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_quirk_intel_spt_pch_acs }, > >> { 0x19a2, 0x710, pci_quirk_mf_endpoint_acs }, /* Emulex BE3-R */ > >> { 0x10df, 0x720, pci_quirk_mf_endpoint_acs }, /* Emulex Skyhawk-R */ > >> - /* Cavium ThunderX */ > >> - { PCI_VENDOR_ID_CAVIUM, PCI_ANY_ID, pci_quirk_cavium_acs }, > >> { 0 } > >> }; > >> > >> >