From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3419CC433DF for ; Fri, 10 Jul 2020 20:29:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0063D2077D for ; Fri, 10 Jul 2020 20:29:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594412966; bh=DiQoR/qIH6L3RLjeyhUKDGJQxa1UAOogxnzXV3WwyYM=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=tRm6B2VJ52vZgH3QGN7N61tCORJHW8yb97WdNc39UIQlEwXAzslt2+2drwBsPZ7SN e/FKOle7AApQ2ZuihOCe2jPOHF/86X4Uigrz5zLkomP7UyV02raldSuchpYF6zRkx1 ygh9bIkE1HnFsK7JvVyv6LfUW8qk6+r05rH7Q0U8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726965AbgGJU3Z (ORCPT ); Fri, 10 Jul 2020 16:29:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:53848 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726832AbgGJU3Y (ORCPT ); Fri, 10 Jul 2020 16:29:24 -0400 Received: from localhost (mobile-166-175-191-139.mycingular.net [166.175.191.139]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 01EEA20748; Fri, 10 Jul 2020 20:29:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594412964; bh=DiQoR/qIH6L3RLjeyhUKDGJQxa1UAOogxnzXV3WwyYM=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=Mg98WBUBOpphkDnIHW8UWq9hjz21UEVfEZUm2hCYj4fI3Z3Pd0mvcodlBgh3hPfQR 8i6qn/ymwX6+Hwn75+YwG8EoV/evuOSi7qZEpRc4q3e858ej7z4C76bhgqNhGmxHlC v0NqnH5iKyuPe4eCHax/Um6J0l3evRwJGkibQ3jg= Date: Fri, 10 Jul 2020 15:29:22 -0500 From: Bjorn Helgaas To: Rajat Jain Cc: David Woodhouse , Lu Baolu , Joerg Roedel , Bjorn Helgaas , "Rafael J. Wysocki" , Len Brown , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, Raj Ashok , lalithambika.krishnakumar@intel.com, Mika Westerberg , Jean-Philippe Brucker , Prashant Malani , Benson Leung , Todd Broch , Alex Levin , Mattias Nissler , Rajat Jain , Bernie Keany , Aaron Durbin , Diego Rivas , Duncan Laurie , Furquan Shaikh , Jesse Barnes , Christian Kellner , Alex Williamson , Greg Kroah-Hartman , oohall@gmail.com, Saravana Kannan , Suzuki K Poulose , Arnd Bergmann , Heikki Krogerus Subject: Re: [PATCH v4 4/4] PCI/ACS: Enable PCI_ACS_TB for untrusted/external-facing devices Message-ID: <20200710202922.GA77140@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200707224604.3737893-4-rajatja@google.com> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Tue, Jul 07, 2020 at 03:46:04PM -0700, Rajat Jain wrote: > When enabling ACS, enable translation blocking for external facing ports > and untrusted devices. > > Signed-off-by: Rajat Jain > --- > v4: Add braces to avoid warning from kernel robot > print warning for only external-facing devices. > v3: print warning if ACS_TB not supported on external-facing/untrusted ports. > Minor code comments fixes. > v2: Commit log change > > drivers/pci/pci.c | 8 ++++++++ > drivers/pci/quirks.c | 15 +++++++++++++++ > 2 files changed, 23 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 73a8627822140..a5a6bea7af7ce 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -876,6 +876,14 @@ static void pci_std_enable_acs(struct pci_dev *dev) > /* Upstream Forwarding */ > ctrl |= (cap & PCI_ACS_UF); > > + /* Enable Translation Blocking for external devices */ > + if (dev->external_facing || dev->untrusted) { > + if (cap & PCI_ACS_TB) > + ctrl |= PCI_ACS_TB; > + else if (dev->external_facing) > + pci_warn(dev, "ACS: No Translation Blocking on external-facing dev\n"); > + } IIUC, this means that external devices can *never* use ATS and can never cache translations. And (I guess, I'm not an expert) it can also never use the Page Request Services? Is this what we want? Do we have any idea how many external devices this will affect or how much of a performance impact they will see? Do we need some kind of override or mechanism to authenticate certain devices so they can use ATS and PRI? If we do decide this is the right thing to do, I think we need to expand the commit log a bit, because this is potentially a significant user-visible change. > pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl); > } > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index b341628e47527..bb22b46c1d719 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -4934,6 +4934,13 @@ static void pci_quirk_enable_intel_rp_mpc_acs(struct pci_dev *dev) > } > } > > +/* > + * Currently this quirk does the equivalent of > + * PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF > + * > + * TODO: This quirk also needs to do equivalent of PCI_ACS_TB, > + * if dev->external_facing || dev->untrusted > + */ > static int pci_quirk_enable_intel_pch_acs(struct pci_dev *dev) > { > if (!pci_quirk_intel_pch_acs_match(dev)) > @@ -4973,6 +4980,14 @@ static int pci_quirk_enable_intel_spt_pch_acs(struct pci_dev *dev) > ctrl |= (cap & PCI_ACS_CR); > ctrl |= (cap & PCI_ACS_UF); > > + /* Enable Translation Blocking for external devices */ > + if (dev->external_facing || dev->untrusted) { > + if (cap & PCI_ACS_TB) > + ctrl |= PCI_ACS_TB; > + else if (dev->external_facing) > + pci_warn(dev, "ACS: No Translation Blocking on external-facing dev\n"); > + } > + > pci_write_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, ctrl); > > pci_info(dev, "Intel SPT PCH root port ACS workaround enabled\n"); > -- > 2.27.0.212.ge8ba1cc988-goog >