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, URIBL_BLOCKED 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 2784FC433E0 for ; Fri, 15 May 2020 21:18:35 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 83900205CB for ; Fri, 15 May 2020 21:18:34 +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="iYw1rXpY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 83900205CB 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 hemlock.osuosl.org (Postfix) with ESMTP id 407DE89689; Fri, 15 May 2020 21:18:34 +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 QD1rbxOJqmdq; Fri, 15 May 2020 21:18:29 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 92E1189569; Fri, 15 May 2020 21:18:29 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 841EBC0859; Fri, 15 May 2020 21:18:29 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id A8B33C016F for ; Fri, 15 May 2020 21:18:27 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 9D8AC87E6A for ; Fri, 15 May 2020 21:18:27 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pjpvGu8AAkTR for ; Fri, 15 May 2020 21:18:23 +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 fraxinus.osuosl.org (Postfix) with ESMTPS id 6E2FD87E09 for ; Fri, 15 May 2020 21:18:23 +0000 (UTC) Received: from localhost (mobile-166-175-190-200.mycingular.net [166.175.190.200]) (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 99B7F205CB; Fri, 15 May 2020 21:18:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589577503; bh=ZQ43XWvnomP6iief7qgRRbmyG/Bi9bziKV7eLxey5z8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=iYw1rXpYC7+iTiovQH69ZJN7ikDy6fxVEhYEdV1ssHJazsWRNLymxAPARP3cwPsrF MgKv6QPMsHDyZenI3gXiYZA2LWLuoVh7agD+i9unX1itmKntZUFYS9KRoZeKACj6y1 SvAGo7FPYdfzQx+wZlqZKyL/uju5rWadJrrwKKik= Date: Fri, 15 May 2020 16:18:20 -0500 From: Bjorn Helgaas To: Jean-Philippe Brucker Subject: Re: [PATCH 1/4] PCI/ATS: Only enable ATS for trusted devices Message-ID: <20200515211820.GA545575@bjorn-Precision-5520> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200515104359.1178606-2-jean-philippe@linaro.org> Cc: alex.williamson@redhat.com, ashok.raj@intel.com, linux-pci@vger.kernel.org, robin.murphy@arm.com, iommu@lists.linux-foundation.org, bhelgaas@google.com, will@kernel.org, dwmw2@infradead.org, linux-arm-kernel@lists.infradead.org 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 Fri, May 15, 2020 at 12:43:59PM +0200, Jean-Philippe Brucker wrote: > Add pci_ats_supported(), which checks whether a device has an ATS > capability, and whether it is trusted. A device is untrusted if it is > plugged into an external-facing port such as Thunderbolt and could be > spoof an existing device to exploit weaknesses in the IOMMU > configuration. PCIe ATS is one such weaknesses since it allows > endpoints to cache IOMMU translations and emit transactions with > 'Translated' Address Type (10b) that partially bypass the IOMMU > translation. > > The SMMUv3 and VT-d IOMMU drivers already disallow ATS and transactions > with 'Translated' Address Type for untrusted devices. Add the check to > pci_enable_ats() to let other drivers (AMD IOMMU for now) benefit from > it. > > By checking ats_cap, the pci_ats_supported() helper also returns whether > ATS was globally disabled with pci=noats, and could later include more > things, for example whether the whole PCIe hierarchy down to the > endpoint supports ATS. > > Signed-off-by: Jean-Philippe Brucker Acked-by: Bjorn Helgaas > --- > include/linux/pci-ats.h | 3 +++ > drivers/pci/ats.c | 18 +++++++++++++++++- > 2 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h > index d08f0869f1213e..f75c307f346de9 100644 > --- a/include/linux/pci-ats.h > +++ b/include/linux/pci-ats.h > @@ -6,11 +6,14 @@ > > #ifdef CONFIG_PCI_ATS > /* Address Translation Service */ > +bool pci_ats_supported(struct pci_dev *dev); > int pci_enable_ats(struct pci_dev *dev, int ps); > void pci_disable_ats(struct pci_dev *dev); > int pci_ats_queue_depth(struct pci_dev *dev); > int pci_ats_page_aligned(struct pci_dev *dev); > #else /* CONFIG_PCI_ATS */ > +static inline bool pci_ats_supported(struct pci_dev *d) > +{ return false; } > static inline int pci_enable_ats(struct pci_dev *d, int ps) > { return -ENODEV; } > static inline void pci_disable_ats(struct pci_dev *d) { } > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > index 390e92f2d8d1fc..15fa0c37fd8e44 100644 > --- a/drivers/pci/ats.c > +++ b/drivers/pci/ats.c > @@ -30,6 +30,22 @@ void pci_ats_init(struct pci_dev *dev) > dev->ats_cap = pos; > } > > +/** > + * pci_ats_supported - check if the device can use ATS > + * @dev: the PCI device > + * > + * Returns true if the device supports ATS and is allowed to use it, false > + * otherwise. > + */ > +bool pci_ats_supported(struct pci_dev *dev) > +{ > + if (!dev->ats_cap) > + return false; > + > + return !dev->untrusted; > +} > +EXPORT_SYMBOL_GPL(pci_ats_supported); > + > /** > * pci_enable_ats - enable the ATS capability > * @dev: the PCI device > @@ -42,7 +58,7 @@ int pci_enable_ats(struct pci_dev *dev, int ps) > u16 ctrl; > struct pci_dev *pdev; > > - if (!dev->ats_cap) > + if (!pci_ats_supported(dev)) > return -EINVAL; > > if (WARN_ON(dev->ats_enabled)) > -- > 2.26.2 > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu