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 04321C282C2 for ; Wed, 13 Feb 2019 10:40:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF95221920 for ; Wed, 13 Feb 2019 10:40:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391515AbfBMKkA (ORCPT ); Wed, 13 Feb 2019 05:40:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54710 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727058AbfBMKkA (ORCPT ); Wed, 13 Feb 2019 05:40:00 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E6E3289AD3; Wed, 13 Feb 2019 10:39:59 +0000 (UTC) Received: from [10.36.116.102] (ovpn-116-102.ams2.redhat.com [10.36.116.102]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DEBF760856; Wed, 13 Feb 2019 10:39:51 +0000 (UTC) Subject: Re: [PATCH] vfio_pci: Enable memory accesses before calling pci_map_rom To: eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, alex.williamson@redhat.com References: <20190213101406.3934-1-eric.auger@redhat.com> From: Auger Eric Message-ID: Date: Wed, 13 Feb 2019 11:39:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190213101406.3934-1-eric.auger@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 13 Feb 2019 10:39:59 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 2/13/19 11:14 AM, Eric Auger wrote: > 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); > + } I failed to re-enable in case of error. I will respin. Thanks Eric > + > info.flags = VFIO_REGION_INFO_FLAG_READ; > break; > } >