From patchwork Sat Oct 30 13:53:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dongdong Liu X-Patchwork-Id: 12594345 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3040EC4167E for ; Sat, 30 Oct 2021 13:57:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1968060FD9 for ; Sat, 30 Oct 2021 13:57:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231939AbhJ3OAG (ORCPT ); Sat, 30 Oct 2021 10:00:06 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:15319 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230125AbhJ3OAE (ORCPT ); Sat, 30 Oct 2021 10:00:04 -0400 Received: from dggeme758-chm.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4HhLTK5kfJz90PN; Sat, 30 Oct 2021 21:57:25 +0800 (CST) Received: from SZX1000464847.huawei.com (10.21.59.169) by dggeme758-chm.china.huawei.com (10.3.19.104) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.15; Sat, 30 Oct 2021 21:57:31 +0800 From: Dongdong Liu To: , , , , , , , CC: , Subject: [PATCH V11 6/8] PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA Date: Sat, 30 Oct 2021 21:53:46 +0800 Message-ID: <20211030135348.61364-7-liudongdong3@huawei.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20211030135348.61364-1-liudongdong3@huawei.com> References: <20211030135348.61364-1-liudongdong3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.21.59.169] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggeme758-chm.china.huawei.com (10.3.19.104) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The P2PDMA mapping should fail if a device with 10-Bit Tag Requester interact with a device that does not support 10-Bit Tag Completer. Add a 10-Bit Tag check in the P2PDMA code to ensure that a device with 10-Bit Tag Requester doesn't interact with a device that does not support 10-Bit Tag Completer. Before that happens, the kernel should emit a warning. "echo 0 > /sys/bus/pci/devices/.../tags" to disable 10-Bit Tag Requester for PF device. "echo 0 > /sys/bus/pci/devices/.../sriov_vf_tags_ctl" to disable 10-Bit Tag Requester for VF device. Signed-off-by: Dongdong Liu Reviewed-by: Logan Gunthorpe --- drivers/pci/p2pdma.c | 48 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 50cdde3e9a8b..1565a31183af 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -19,6 +19,7 @@ #include #include #include +#include "pci.h" enum pci_p2pdma_map_type { PCI_P2PDMA_MAP_UNKNOWN = 0, @@ -410,6 +411,50 @@ static unsigned long map_types_idx(struct pci_dev *client) (client->bus->number << 8) | client->devfn; } +static bool pci_10bit_tags_unsupported(struct pci_dev *a, + struct pci_dev *b, + bool verbose) +{ + bool req; + bool comp; + u16 ctl; + const char *str = "tags"; + + if (a->is_virtfn) { +#ifdef CONFIG_PCI_IOV + req = !!(a->physfn->sriov->ctrl & + PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN); +#endif + } else { + pcie_capability_read_word(a, PCI_EXP_DEVCTL2, &ctl); + req = !!(ctl & PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN); + } + + comp = !!(b->devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_COMP); + + /* 10-bit tags not enabled on requester */ + if (!req) + return false; + + /* Completer can handle anything */ + if (comp) + return false; + + if (!verbose) + return true; + + pci_warn(a, "cannot be used for peer-to-peer DMA as 10-Bit Tag Requester enable is set for this device, but peer device (%s) does not support the 10-Bit Tag Completer\n", + pci_name(b)); + + if (a->is_virtfn) + str = "sriov_vf_tags_ctl"; + + pci_warn(a, "to disable 10-Bit Tag Requester for this device, echo 0 > /sys/bus/pci/devices/%s/%s\n", + pci_name(a), str); + + return true; +} + /* * Calculate the P2PDMA mapping type and distance between two PCI devices. * @@ -532,6 +577,9 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client, map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED; } done: + if (pci_10bit_tags_unsupported(client, provider, verbose)) + map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED; + rcu_read_lock(); p2pdma = rcu_dereference(provider->p2pdma); if (p2pdma)