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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 91886C11D3D for ; Thu, 27 Feb 2020 14:47:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A2E524697 for ; Thu, 27 Feb 2020 14:47:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582814852; bh=VbA5W/1MQw39uQmgUFgE7TT+W50DNHyHc3w7JLP4rPg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YXikyAjYQJfCJTBP2FnHcEVYDzKh8jOmR2DK5H361zuEbwzUTq3dUpS935X0UW788 i5C03NfEiqxQEdX8DcO56Vjvo1FP9z8TRmPTJ+xtRM2B9l8n75BLAt04sJg04HgKrc vaMoy43tPdVNq4DAW6Y3SN1fwpzczaEJoSYZ1ECU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730143AbgB0NoH (ORCPT ); Thu, 27 Feb 2020 08:44:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:39508 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730139AbgB0NoH (ORCPT ); Thu, 27 Feb 2020 08:44:07 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 B516120578; Thu, 27 Feb 2020 13:44:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811045; bh=VbA5W/1MQw39uQmgUFgE7TT+W50DNHyHc3w7JLP4rPg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ypLKyzXNwgSCRa9rHkRsGPvdOfK7fwFDAiNSLvsGaVGrRcbBPGIFOL0L13TrUkLoA a8wLJnfLlzmjWHitOsqMHkgla6t/5SrT2zskA5mzdo0sVTCVI+SYPn+evxTaqi0bLF Nxgo83QIqGaFks3czV2LZqEYV7nCzbv6+Uqu/STE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kit Chow , Logan Gunthorpe , Bjorn Helgaas , Sasha Levin Subject: [PATCH 4.4 058/113] PCI: Dont disable bridge BARs when assigning bus resources Date: Thu, 27 Feb 2020 14:36:14 +0100 Message-Id: <20200227132221.014026556@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132211.791484803@linuxfoundation.org> References: <20200227132211.791484803@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Logan Gunthorpe [ Upstream commit 9db8dc6d0785225c42a37be7b44d1b07b31b8957 ] Some PCI bridges implement BARs in addition to bridge windows. For example, here's a PLX switch: 04:00.0 PCI bridge: PLX Technology, Inc. PEX 8724 24-Lane, 6-Port PCI Express Gen 3 (8 GT/s) Switch, 19 x 19mm FCBGA (rev ca) (prog-if 00 [Normal decode]) Flags: bus master, fast devsel, latency 0, IRQ 30, NUMA node 0 Memory at 90a00000 (32-bit, non-prefetchable) [size=256K] Bus: primary=04, secondary=05, subordinate=0a, sec-latency=0 I/O behind bridge: 00002000-00003fff Memory behind bridge: 90000000-909fffff Prefetchable memory behind bridge: 0000380000800000-0000380000bfffff Previously, when the kernel assigned resource addresses (with the pci=realloc command line parameter, for example) it could clear the struct resource corresponding to the BAR. When this happened, lspci would report this BAR as "ignored": Region 0: Memory at (32-bit, non-prefetchable) [size=256K] This is because the kernel reports a zero start address and zero flags in the corresponding sysfs resource file and in /proc/bus/pci/devices. Investigation with 'lspci -x', however, shows the BIOS-assigned address will still be programmed in the device's BAR registers. It's clearly a bug that the kernel lost track of the BAR value, but in most cases, this still won't result in a visible issue because nothing uses the memory, so nothing is affected. However, when an IOMMU is in use, it will not reserve this space in the IOVA because the kernel no longer thinks the range is valid. (See dmar_init_reserved_ranges() for the Intel implementation of this.) Without the proper reserved range, a DMA mapping may allocate an IOVA that matches a bridge BAR, which results in DMA accesses going to the BAR instead of the intended RAM. The problem was in pci_assign_unassigned_root_bus_resources(). When any resource from a bridge device fails to get assigned, the code set the resource's flags to zero. This makes sense for bridge windows, as they will be re-enabled later, but for regular BARs, it makes the kernel permanently lose track of the fact that they decode address space. Change pci_assign_unassigned_root_bus_resources() and pci_assign_unassigned_bridge_resources() so they only clear "res->flags" for bridge *windows*, not bridge BARs. Fixes: da7822e5ad71 ("PCI: update bridge resources to get more big ranges when allocating space (again)") Link: https://lore.kernel.org/r/20200108213208.4612-1-logang@deltatee.com [bhelgaas: commit log, check for pci_is_bridge()] Reported-by: Kit Chow Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Signed-off-by: Sasha Levin --- drivers/pci/setup-bus.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 1723ac1b30e10..fe2865a0da395 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1760,12 +1760,18 @@ again: /* restore size and flags */ list_for_each_entry(fail_res, &fail_head, list) { struct resource *res = fail_res->res; + int idx; res->start = fail_res->start; res->end = fail_res->end; res->flags = fail_res->flags; - if (fail_res->dev->subordinate) - res->flags = 0; + + if (pci_is_bridge(fail_res->dev)) { + idx = res - &fail_res->dev->resource[0]; + if (idx >= PCI_BRIDGE_RESOURCES && + idx <= PCI_BRIDGE_RESOURCE_END) + res->flags = 0; + } } free_list(&fail_head); @@ -1826,12 +1832,18 @@ again: /* restore size and flags */ list_for_each_entry(fail_res, &fail_head, list) { struct resource *res = fail_res->res; + int idx; res->start = fail_res->start; res->end = fail_res->end; res->flags = fail_res->flags; - if (fail_res->dev->subordinate) - res->flags = 0; + + if (pci_is_bridge(fail_res->dev)) { + idx = res - &fail_res->dev->resource[0]; + if (idx >= PCI_BRIDGE_RESOURCES && + idx <= PCI_BRIDGE_RESOURCE_END) + res->flags = 0; + } } free_list(&fail_head); -- 2.20.1