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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 A3D53C3B1A1 for ; Fri, 14 Feb 2020 17:28:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DA1B24650 for ; Fri, 14 Feb 2020 17:28:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581701298; bh=x7sw3HRxfEHEX1Ax+eGUS8pRpBWe8NIuHfYdorZmjqo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QCVvANdmwyOXcQSebfo3ZGuksCA3cxj6HBv2gk1H4wgCgeNDB3WFwpnJuHLj3AAqz 8j9pNuQOsrkBbZwM00934k/rP3666oyDRPOKSJCIu1/jU77feLLsa+3qk4uNf92aKL epQ8oIhsB/L4CFm6+2k05NZLtVb2xicBZcy8SBxM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390509AbgBNR2O (ORCPT ); Fri, 14 Feb 2020 12:28:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:59978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390855AbgBNQII (ORCPT ); Fri, 14 Feb 2020 11:08:08 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D690322314; Fri, 14 Feb 2020 16:08:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696487; bh=x7sw3HRxfEHEX1Ax+eGUS8pRpBWe8NIuHfYdorZmjqo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tP06EpJtxJLfmtAz3NJ3gEpuiW7b7dYujP0MgDmyDAh00MPxH/y3KQR6USffl6GQg ZuABup5W7yjW1T9nnNl9wEUvMw9KcYTT2LLuj0vL/Svl8gjoXtJz6FWxbZ3rYYR05h lEh1eVt/kyEXPRdPRqwBvO2Vd7b1EVhbddWatc2Q= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Logan Gunthorpe , Kit Chow , Bjorn Helgaas , Sasha Levin , linux-pci@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 293/459] PCI: Don't disable bridge BARs when assigning bus resources Date: Fri, 14 Feb 2020 10:59:03 -0500 Message-Id: <20200214160149.11681-293-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214160149.11681-1-sashal@kernel.org> References: <20200214160149.11681-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@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 e7dbe21705ba5..5356630e0e483 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1785,12 +1785,18 @@ void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus) /* 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); @@ -2037,12 +2043,18 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge) /* 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