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 B86DEC43381 for ; Tue, 19 Feb 2019 21:47:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F245208E4 for ; Tue, 19 Feb 2019 21:47:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729717AbfBSVr6 (ORCPT ); Tue, 19 Feb 2019 16:47:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36598 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725994AbfBSVr5 (ORCPT ); Tue, 19 Feb 2019 16:47:57 -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 7B652806A8; Tue, 19 Feb 2019 21:47:57 +0000 (UTC) Received: from w520.home (ovpn-116-24.phx2.redhat.com [10.3.116.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2A01B66076; Tue, 19 Feb 2019 21:47:55 +0000 (UTC) Date: Tue, 19 Feb 2019 14:47:54 -0700 From: Alex Williamson To: Eric Auger Cc: eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v3] vfio_pci: Enable memory accesses before calling pci_map_rom Message-ID: <20190219144754.278fb075@w520.home> In-Reply-To: <20190215161606.32334-1-eric.auger@redhat.com> References: <20190215161606.32334-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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]); Tue, 19 Feb 2019 21:47:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 15 Feb 2019 17:16:06 +0100 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 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 Applied to vfio next branch for v5.1. Thanks, Alex > --- > 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: