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 C7990C282C2 for ; Wed, 13 Feb 2019 10:14:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B57F2190A for ; Wed, 13 Feb 2019 10:14:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388592AbfBMKOV (ORCPT ); Wed, 13 Feb 2019 05:14:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42634 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728116AbfBMKOV (ORCPT ); Wed, 13 Feb 2019 05:14:21 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 33B0413CE3; Wed, 13 Feb 2019 10:14:21 +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 9B3DB5D6B3; Wed, 13 Feb 2019 10:14:11 +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] vfio_pci: Enable memory accesses before calling pci_map_rom Date: Wed, 13 Feb 2019 11:14:06 +0100 Message-Id: <20190213101406.3934-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 13 Feb 2019 10:14:21 +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 crash the host with a synchronous external abort (aarch64). In case memory accesses were disabled, re-enable them before the call and disable them back again just after. Signed-off-by: Eric Auger --- drivers/vfio/pci/vfio_pci.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index ff60bd1ea587..96b8bbd909d7 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -706,8 +706,10 @@ static long vfio_pci_ioctl(void *device_data, break; case VFIO_PCI_ROM_REGION_INDEX: { + bool mem_access_disabled; void __iomem *io; size_t size; + u16 cmd; info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index); info.flags = 0; @@ -723,6 +725,13 @@ static long vfio_pci_ioctl(void *device_data, break; } + pci_read_config_word(pdev, PCI_COMMAND, &cmd); + mem_access_disabled = !(cmd & PCI_COMMAND_MEMORY); + if (mem_access_disabled) { + cmd |= PCI_COMMAND_MEMORY; + pci_write_config_word(pdev, PCI_COMMAND, cmd); + } + /* Is it really there? */ io = pci_map_rom(pdev, &size); if (!io || !size) { @@ -731,6 +740,11 @@ static long vfio_pci_ioctl(void *device_data, } pci_unmap_rom(pdev, io); + if (mem_access_disabled) { + cmd &= ~PCI_COMMAND_MEMORY; + pci_write_config_word(pdev, PCI_COMMAND, cmd); + } + info.flags = VFIO_REGION_INFO_FLAG_READ; break; } -- 2.20.1