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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 88C61C43381 for ; Fri, 15 Feb 2019 16:16:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FF462192B for ; Fri, 15 Feb 2019 16:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728421AbfBOQQk (ORCPT ); Fri, 15 Feb 2019 11:16:40 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34696 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726000AbfBOQQg (ORCPT ); Fri, 15 Feb 2019 11:16:36 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BC941FD3C2; Fri, 15 Feb 2019 16:16:35 +0000 (UTC) Received: from laptop.redhat.com (ovpn-116-102.ams2.redhat.com [10.36.116.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id F323660C6F; Fri, 15 Feb 2019 16:16:27 +0000 (UTC) From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, alex.williamson@redhat.com Subject: [PATCH v3] vfio_pci: Enable memory accesses before calling pci_map_rom Date: Fri, 15 Feb 2019 17:16:06 +0100 Message-Id: <20190215161606.32334-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 15 Feb 2019 16:16:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pci_map_rom/pci_get_rom_size() performs memory access in the ROM. In case the Memory Space accesses were disabled, readw() is likely to trigger a synchronous external abort on some platforms. In case memory accesses were disabled, re-enable them before the call and disable them back again just after. Fixes: 89e1f7d4c66d ("vfio: Add PCI device driver") Signed-off-by: Eric Auger Suggested-by: Alex Williamson --- v2 -> v3: - follow Alex re-writing v1 -> v2: - also re-enable in case of error --- drivers/vfio/pci/vfio_pci.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index ff60bd1ea587..4b0d30f1eabc 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -708,6 +708,7 @@ static long vfio_pci_ioctl(void *device_data, { void __iomem *io; size_t size; + u16 orig_cmd; info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index); info.flags = 0; @@ -723,15 +724,23 @@ static long vfio_pci_ioctl(void *device_data, break; } - /* Is it really there? */ - io = pci_map_rom(pdev, &size); - if (!io || !size) { - info.size = 0; - break; - } - pci_unmap_rom(pdev, io); + /* + * Is it really there? Enable memory decode for + * implicit access in pci_map_rom(). + */ + pci_read_config_word(pdev, PCI_COMMAND, &orig_cmd); + pci_write_config_word(pdev, PCI_COMMAND, + orig_cmd | PCI_COMMAND_MEMORY); - info.flags = VFIO_REGION_INFO_FLAG_READ; + io = pci_map_rom(pdev, &size); + if (io) { + info.flags = VFIO_REGION_INFO_FLAG_READ; + pci_unmap_rom(pdev, io); + } else { + info.size = 0; + } + + pci_write_config_word(pdev, PCI_COMMAND, orig_cmd); break; } case VFIO_PCI_VGA_REGION_INDEX: -- 2.20.1