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=-9.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,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 1AA3AC433E4 for ; Tue, 14 Jul 2020 20:19:50 +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 D111B207DD for ; Tue, 14 Jul 2020 20:19:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="ktzGRdNH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D111B207DD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lists.linux-foundation.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 8542689A01; Tue, 14 Jul 2020 20:19:49 +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 FpMU+ikc9iSa; Tue, 14 Jul 2020 20:19:48 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 362E6899ED; Tue, 14 Jul 2020 20:19:48 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0E0C0C0888; Tue, 14 Jul 2020 20:19:48 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id A622FC0733 for ; Tue, 14 Jul 2020 20:19:46 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 83E0486C6A for ; Tue, 14 Jul 2020 20:19:46 +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 7w0B5DLljOpq for ; Tue, 14 Jul 2020 20:19:45 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-lj1-f196.google.com (mail-lj1-f196.google.com [209.85.208.196]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 0CEC386C48 for ; Tue, 14 Jul 2020 20:19:44 +0000 (UTC) Received: by mail-lj1-f196.google.com with SMTP id h22so25208443lji.9 for ; Tue, 14 Jul 2020 13:19:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=XWpCwFxzq2ITP3K2PgbPEPYflHGc9CASEeamyGhecg4=; b=ktzGRdNHxUc/NOjGB1vSjjeBZhP/eN1zV/MJ3JD8wmxjdxCf0IQ+zpHExTOeKFCy+a lkIxtWm6PjqYkFHafKjnDH7YyMKXwotc5q6DnqSw3TopHIRLxHCs+deg6PTyFFdIXYFv k7EKTWOzzY2ectIvYgQJoT3PC8WtQ36MwQGEEdeS4yRKsH7OHceijsqk6ydBx4RUmYvR IZrllP4JBOp0cXppgKAXu1mmq6yPSvexe7a431gzpco6kw0dfLio0xngHrY49l7HSD+o /v/hKsd9rStGhPgfKDu4Tzc6hz5W+DzX3Fs66+EIKtMQGOTLMOIPGhjlXHu/EB8LfYrq 3KdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=XWpCwFxzq2ITP3K2PgbPEPYflHGc9CASEeamyGhecg4=; b=lH+QXa/edHkz8tcHNVzz17y4k9xlsT+LrmIeMTplPi8XOAmt1qMEHvT3fEPDhN+zbf hcne6ghMCA9B0zSLOGbS5zxpvhjr2zyrTRu4rMtZ8EjPFBc2H0zDwABV8uyBv+diQkc5 asfDicPHXqLGl+AYxU+PCrTE5U7E3umxAQ3CMADGffRG4uRmBo4u7x0+GMQekt/lIL7y 62DjvdKWI4Nbe2KugUSGMI5jAHegOld5qAzkaqYv6GdCamQ5LtiFbc1ZYDcK4z/5+/De eCjhvExA3Hwiax4I8dw0cPhR00dp0koihzgjyFkGrx/JD9v4EeQDsSfd09V/NURRWaDs rFOA== X-Gm-Message-State: AOAM533/Wu4EDHzQQfSpq4YiH4oMZlHCXtXHinziwEodQDS8IFqoIXMh xtZCDwNSuMysxE+5AxgGl5ieJBQ3Nq4V8k1DElIxFg== X-Google-Smtp-Source: ABdhPJyog1559G29m5pJ504Xf+0cH4eNg4/1fwwOhATAWoZMeuV+BZE2PrcQIEm6ttR2VLYvOaa4/0qm67q9Isa6wdw= X-Received: by 2002:a2e:8199:: with SMTP id e25mr2844648ljg.307.1594757982632; Tue, 14 Jul 2020 13:19:42 -0700 (PDT) MIME-Version: 1.0 References: <20200711195346.GA132330@bjorn-Precision-5520> In-Reply-To: <20200711195346.GA132330@bjorn-Precision-5520> Date: Tue, 14 Jul 2020 13:19:05 -0700 Message-ID: Subject: Re: [PATCH v4 4/4] PCI/ACS: Enable PCI_ACS_TB for untrusted/external-facing devices To: Bjorn Helgaas Cc: Todd Broch , linux-pci , "Krishnakumar, Lalithambika" , Heikki Krogerus , Diego Rivas , Jean-Philippe Brucker , Furquan Shaikh , "Raj, Ashok" , Saravana Kannan , ACPI Devel Maling List , 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 Mailing List , "open list:AMD IOMMU \(AMD-VI\)" , Arnd Bergmann , Oliver O'Halloran , 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: , From: Rajat Jain via iommu Reply-To: Rajat Jain Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Sat, Jul 11, 2020 at 12:53 PM Bjorn Helgaas wrote: > > On Fri, Jul 10, 2020 at 03:53:59PM -0700, Rajat Jain wrote: > > On Fri, Jul 10, 2020 at 2:29 PM Raj, Ashok wrote: > > > On Fri, Jul 10, 2020 at 03:29:22PM -0500, Bjorn Helgaas wrote: > > > > 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. > > > > Yes, but it already exists today (and this patch doesn't change that): > > 521376741b2c2 "PCI/ATS: Only enable ATS for trusted devices" > > > > IMHO any external device trying to send ATS traffic despite having ATS > > disabled should count as a bad intent. And this patch is trying to > > plug that loophole, by blocking the AT traffic from devices that we do > > not expect to see AT from anyway. > > Thinking about this some more, I wonder if Linux should: > > - Explicitly disable ATS for every device at enumeration-time, e.g., > in pci_init_capabilities(), > > - Enable PCI_ACS_TB for every device (not just external-facing or > untrusted ones), > > - Disable PCI_ACS_TB for the relevant devices along the path only > when enabling ATS. > > One nice thing about doing that is that the "untrusted" test would be > only in pci_enable_ats(), and we wouldn't need one in > pci_std_enable_acs(). Sent out v5 with this approach here: https://patchwork.kernel.org/patch/11663515/ Thanks, Rajat > > > It's possible BIOS gives us devices with ATS enabled, and this might > break them, but that seems like something we'd want to find out about. > > Bjorn _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu