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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 ACE0BC433E3 for ; Thu, 28 May 2020 21:54:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 911FA206F1 for ; Thu, 28 May 2020 21:54:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436804AbgE1VyX (ORCPT ); Thu, 28 May 2020 17:54:23 -0400 Received: from mga11.intel.com ([192.55.52.93]:63426 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2436802AbgE1VyU (ORCPT ); Thu, 28 May 2020 17:54:20 -0400 IronPort-SDR: GE38C1nDbQcpphXmhQGFrKwJVBzKVHGAml8U+hi+GX0nrhhTMTH+6xC/D/STZgCIDAZp4Jbo1X yiMLmnKXV3Cw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2020 14:54:19 -0700 IronPort-SDR: eO+Kl9oDStjHmcS70yoy4o+yy64ToFP18+zRaQYBdY1tP9NOd2yExlkgOb/XN5teEyzh5kvODQ imGIuX5A4rvw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,446,1583222400"; d="scan'208";a="469288930" Received: from ssp-nc-cdi361.jf.intel.com (HELO otc-nc-03) ([10.54.39.25]) by fmsmga006.fm.intel.com with ESMTP; 28 May 2020 14:54:18 -0700 Date: Thu, 28 May 2020 14:54:18 -0700 From: "Raj, Ashok" To: Alex Williamson Cc: linux-pci@vger.kernel.org, Bjorn Helgaas , Joerg Roedel , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Lu Baolu , Darrel Goeddel , Mark Scott , Romil Sharma , Ashok Raj Subject: Re: [PATCH] PCI: Relax ACS requirement for Intel RCiEP devices. Message-ID: <20200528215418.GA7173@otc-nc-03> References: <1590699462-7131-1-git-send-email-ashok.raj@intel.com> <20200528153826.257a0145@x1.home> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200528153826.257a0145@x1.home> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, May 28, 2020 at 03:38:26PM -0600, Alex Williamson wrote: > On Thu, 28 May 2020 13:57:42 -0700 > Ashok Raj wrote: > > > All Intel platforms guarantee that all root complex implementations > > must send transactions up to IOMMU for address translations. Hence for > > RCiEP devices that are Vendor ID Intel, can claim exception for lack of > > ACS support. > > > > > > 3.16 Root-Complex Peer to Peer Considerations > > When DMA remapping is enabled, peer-to-peer requests through the > > Root-Complex must be handled > > as follows: > > • The input address in the request is translated (through first-level, > > second-level or nested translation) to a host physical address (HPA). > > The address decoding for peer addresses must be done only on the > > translated HPA. Hardware implementations are free to further limit > > peer-to-peer accesses to specific host physical address regions > > (or to completely disallow peer-forwarding of translated requests). > > • Since address translation changes the contents (address field) of > > the PCI Express Transaction Layer Packet (TLP), for PCI Express > > peer-to-peer requests with ECRC, the Root-Complex hardware must use > > the new ECRC (re-computed with the translated address) if it > > decides to forward the TLP as a peer request. > > • Root-ports, and multi-function root-complex integrated endpoints, may > > support additional peerto-peer control features by supporting PCI Express > > Access Control Services (ACS) capability. Refer to ACS capability in > > PCI Express specifications for details. > > > > Since Linux didn't give special treatment to allow this exception, certain > > RCiEP MFD devices are getting grouped in a single iommu group. This > > doesn't permit a single device to be assigned to a guest for instance. > > > > In one vendor system: Device 14.x were grouped in a single IOMMU group. > > > > /sys/kernel/iommu_groups/5/devices/0000:00:14.0 > > /sys/kernel/iommu_groups/5/devices/0000:00:14.2 > > /sys/kernel/iommu_groups/5/devices/0000:00:14.3 > > > > After the patch: > > /sys/kernel/iommu_groups/5/devices/0000:00:14.0 > > /sys/kernel/iommu_groups/5/devices/0000:00:14.2 > > /sys/kernel/iommu_groups/6/devices/0000:00:14.3 <<< new group > > > > 14.0 and 14.2 are integrated devices, but legacy end points. > > Whereas 14.3 was a PCIe compliant RCiEP. > > > > 00:14.3 Network controller: Intel Corporation Device 9df0 (rev 30) > > Capabilities: [40] Express (v2) Root Complex Integrated Endpoint, MSI 00 > > > > This permits assigning this device to a guest VM. > > > > Fixes: f096c061f552 ("iommu: Rework iommu_group_get_for_pci_dev()") > > I don't really understand this Fixes tag. This seems like a feature, > not a fix. If you want it in stable releases as a feature, request it > via Cc: stable@vger.kernel.org. I'd drop that tag, that's my nit. > Otherwise: Yes, i should have Cced Stable instead. Bjorn: Can you massage this in? or i can resend with Alex's Reviewed-by + adding stable in cc list. > > Reviewed-by: Alex Williamson > > > Signed-off-by: Ashok Raj > > To: Joerg Roedel > > To: Bjorn Helgaas > > Cc: linux-kernel@vger.kernel.org > > Cc: iommu@lists.linux-foundation.org > > Cc: Lu Baolu > > Cc: Alex Williamson > > Cc: Darrel Goeddel > > Cc: Mark Scott , > > Cc: Romil Sharma > > Cc: Ashok Raj > > --- > > v2: Moved functionality from iommu to pci quirks - Alex Williamson > > > > drivers/pci/quirks.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > > index 28c9a2409c50..63373ca0a3fe 100644 > > --- a/drivers/pci/quirks.c > > +++ b/drivers/pci/quirks.c > > @@ -4682,6 +4682,20 @@ static int pci_quirk_mf_endpoint_acs(struct pci_dev *dev, u16 acs_flags) > > PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT); > > } > > > > +static int pci_quirk_rciep_acs(struct pci_dev *dev, u16 acs_flags) > > +{ > > + /* > > + * RCiEP's are required to allow p2p only on translated addresses. > > + * Refer to Intel VT-d specification Section 3.16 Root-Complex Peer > > + * to Peer Considerations > > + */ > > + if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_END) > > + return -ENOTTY; > > + > > + return pci_acs_ctrl_enabled(acs_flags, > > + PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF); > > +} > > + > > static int pci_quirk_brcm_acs(struct pci_dev *dev, u16 acs_flags) > > { > > /* > > @@ -4764,6 +4778,7 @@ static const struct pci_dev_acs_enabled { > > /* I219 */ > > { PCI_VENDOR_ID_INTEL, 0x15b7, pci_quirk_mf_endpoint_acs }, > > { PCI_VENDOR_ID_INTEL, 0x15b8, pci_quirk_mf_endpoint_acs }, > > + { PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_quirk_rciep_acs }, > > /* QCOM QDF2xxx root ports */ > > { PCI_VENDOR_ID_QCOM, 0x0400, pci_quirk_qcom_rp_acs }, > > { PCI_VENDOR_ID_QCOM, 0x0401, pci_quirk_qcom_rp_acs }, >