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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 94C95C433E1 for ; Mon, 6 Jul 2020 16:38:10 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5F830206DF for ; Mon, 6 Jul 2020 16:38:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="gJeMrlVK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F830206DF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 2BFD088B61; Mon, 6 Jul 2020 16:38:10 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id B1tzkmzexrbo; Mon, 6 Jul 2020 16:38:09 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 5E19888B49; Mon, 6 Jul 2020 16:38:09 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 43B74C0891; Mon, 6 Jul 2020 16:38:09 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id CE80BC016F for ; Mon, 6 Jul 2020 16:38:07 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id BA0FA89407 for ; Mon, 6 Jul 2020 16:38:07 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id KwfP-Mp4RnY8 for ; Mon, 6 Jul 2020 16:38:06 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by hemlock.osuosl.org (Postfix) with ESMTPS id E35A389403 for ; Mon, 6 Jul 2020 16:38:06 +0000 (UTC) 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 4DFCA206CD; Mon, 6 Jul 2020 16:38:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594053486; bh=h5Wfn3HjIiXXhkf+M34R0UCWrLS9Ym2zaBVYF7o20HY=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=gJeMrlVKeXf1hw7Srvob2oOpPzBsNGaCeiFEJ+LQzaVKhYbrlKPmFkGdYmrfMFUwc Ld3mkXuOJa9U4mWbnSYaf+Vq4Q5MicOSEBp9KH8DY8/98sorKBQfQISXTBGxc+khFT 8Q+9AXK2ocdqROk8v2rot2AEd87cQF7DZzpa8u0k= Date: Mon, 6 Jul 2020 11:38:05 -0500 From: Bjorn Helgaas To: Rajat Jain Subject: Re: [PATCH v2 2/7] PCI: Set "untrusted" flag for truly external devices only Message-ID: <20200706163805.GA120024@bjorn-Precision-5520> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200630044943.3425049-3-rajatja@google.com> Cc: Todd Broch , linux-pci@vger.kernel.org, lalithambika.krishnakumar@intel.com, Heikki Krogerus , Diego Rivas , Jean-Philippe Brucker , Furquan Shaikh , Raj Ashok , Saravana Kannan , linux-acpi@vger.kernel.org, Christian Kellner , Mattias Nissler , Jesse Barnes , Len Brown , Rajat Jain , Prashant Malani , Suzuki K Poulose , Aaron Durbin , Alex Williamson , Bjorn Helgaas , Mika Westerberg , Bernie Keany , Duncan Laurie , Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Arnd Bergmann , oohall@gmail.com, Benson Leung , David Woodhouse , Alex Levin X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Mon, Jun 29, 2020 at 09:49:38PM -0700, Rajat Jain wrote: > The "ExternalFacing" devices (root ports) are still internal devices that > sit on the internal system fabric and thus trusted. Currently they were > being marked untrusted. > > This patch uses the platform flag to identify the external facing devices > and then use it to mark any downstream devices as "untrusted". The > external-facing devices themselves are left as "trusted". This was > discussed here: https://lkml.org/lkml/2020/6/10/1049 Use the imperative mood in the commit log, as you did for 1/7. E.g., instead of "This patch uses ...", say "Use the platform flag ...". That helps all the commit logs read nicely together. I think this patch makes two changes that should be separated: - Treat "external-facing" devices as internal. - Look for the "external-facing" or "ExternalFacing" property on Switch Downstream Ports as well as Root Ports. > Signed-off-by: Rajat Jain > --- > v2: cosmetic changes in commit log > > drivers/iommu/intel/iommu.c | 2 +- > drivers/pci/of.c | 2 +- > drivers/pci/pci-acpi.c | 13 +++++++------ > drivers/pci/probe.c | 2 +- > include/linux/pci.h | 8 ++++++++ > 5 files changed, 18 insertions(+), 9 deletions(-) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index d759e7234e982..1ccb224f82496 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -4743,7 +4743,7 @@ static inline bool has_untrusted_dev(void) > struct pci_dev *pdev = NULL; > > for_each_pci_dev(pdev) > - if (pdev->untrusted) > + if (pdev->untrusted || pdev->external_facing) I think checking pdev->external_facing is enough for this case, because it's impossible to have pdev->untrusted unless a parent has pdev->external_facing. IIUC, this usage is asking "might we ever have an external device?" as opposed to the "pdev->untrusted" uses, which are asking "is *this* device an external device?" > return true; > > return false; > diff --git a/drivers/pci/of.c b/drivers/pci/of.c > index 27839cd2459f6..22727fc9558df 100644 > --- a/drivers/pci/of.c > +++ b/drivers/pci/of.c > @@ -42,7 +42,7 @@ void pci_set_bus_of_node(struct pci_bus *bus) > } else { > node = of_node_get(bus->self->dev.of_node); > if (node && of_property_read_bool(node, "external-facing")) > - bus->self->untrusted = true; > + bus->self->external_facing = true; > } > > bus->dev.of_node = node; > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c > index 7224b1e5f2a83..492c07805caf8 100644 > --- a/drivers/pci/pci-acpi.c > +++ b/drivers/pci/pci-acpi.c > @@ -1213,22 +1213,23 @@ static void pci_acpi_optimize_delay(struct pci_dev *pdev, > ACPI_FREE(obj); > } > > -static void pci_acpi_set_untrusted(struct pci_dev *dev) > +static void pci_acpi_set_external_facing(struct pci_dev *dev) > { > u8 val; > > - if (pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT) > + if (pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT && > + pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM) This looks like a change worthy of its own patch. We used to look for "ExternalFacingPort" only on Root Ports; now we'll also do it for Switch Downstream Ports. Can you include DT and ACPI spec references if they exist? I found this mention: https://docs.microsoft.com/en-us/windows-hardware/drivers/pci/dsd-for-pcie-root-ports which actually says it should only be implemented for Root Ports. It also mentions a "DmaProperty" that looks related. Maybe Linux should also pay attention to this? If we do change this, should we use pcie_downstream_port(), which includes PCI-to-PCIe bridges as well? > return; > if (device_property_read_u8(&dev->dev, "ExternalFacingPort", &val)) > return; > > /* > - * These root ports expose PCIe (including DMA) outside of the > - * system so make sure we treat them and everything behind as > + * These root/down ports expose PCIe (including DMA) outside of the > + * system so make sure we treat everything behind them as > * untrusted. > */ > if (val) > - dev->untrusted = 1; > + dev->external_facing = 1; > } > > static void pci_acpi_setup(struct device *dev) > @@ -1240,7 +1241,7 @@ static void pci_acpi_setup(struct device *dev) > return; > > pci_acpi_optimize_delay(pci_dev, adev->handle); > - pci_acpi_set_untrusted(pci_dev); > + pci_acpi_set_external_facing(pci_dev); > pci_acpi_add_edr_notifier(pci_dev); > > pci_acpi_add_pm_notifier(adev, pci_dev); > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 6d87066a5ecc5..8c40c00413e74 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1552,7 +1552,7 @@ static void set_pcie_untrusted(struct pci_dev *dev) > * untrusted as well. > */ > parent = pci_upstream_bridge(dev); > - if (parent && parent->untrusted) > + if (parent && (parent->untrusted || parent->external_facing)) > dev->untrusted = true; > } > > diff --git a/include/linux/pci.h b/include/linux/pci.h > index a26be5332bba6..fe1bc603fda40 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -432,6 +432,14 @@ struct pci_dev { > * mappings to make sure they cannot access arbitrary memory. > */ > unsigned int untrusted:1; > + /* > + * Devices are marked as external-facing using info from platform > + * (ACPI / devicetree). An external-facing device is still an internal > + * trusted device, but it faces external untrusted devices. Thus any > + * devices enumerated downstream an external-facing device is marked > + * as untrusted. This comment has a subject/verb agreement problem. > + */ > + unsigned int external_facing:1; > unsigned int broken_intx_masking:1; /* INTx masking can't be used */ > unsigned int io_window_1k:1; /* Intel bridge 1K I/O windows */ > unsigned int irq_managed:1; > -- > 2.27.0.212.ge8ba1cc988-goog > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu