From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934588AbcHNLnE (ORCPT ); Sun, 14 Aug 2016 07:43:04 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52422 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934181AbcHNLcz (ORCPT ); Sun, 14 Aug 2016 07:32:55 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David Vrabel" , "Jan Beulich" , "Boris Ostrovsky" , "Andrey Grodzovsky" Date: Sat, 13 Aug 2016 18:42:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 213/305] xen/pciback: Fix conf_space read/write overlap check. In-Reply-To: X-SA-Exim-Connect-IP: 92.40.249.202 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.37-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Andrey Grodzovsky commit 02ef871ecac290919ea0c783d05da7eedeffc10e upstream. Current overlap check is evaluating to false a case where a filter field is fully contained (proper subset) of a r/w request. This change applies classical overlap check instead to include all the scenarios. More specifically, for (Hilscher GmbH CIFX 50E-DP(M/S)) device driver the logic is such that the entire confspace is read and written in 4 byte chunks. In this case as an example, CACHE_LINE_SIZE, LATENCY_TIMER and PCI_BIST are arriving together in one call to xen_pcibk_config_write() with offset == 0xc and size == 4. With the exsisting overlap check the LATENCY_TIMER field (offset == 0xd, length == 1) is fully contained in the write request and hence is excluded from write, which is incorrect. Signed-off-by: Andrey Grodzovsky Reviewed-by: Boris Ostrovsky Reviewed-by: Jan Beulich Signed-off-by: David Vrabel Signed-off-by: Ben Hutchings --- drivers/xen/xen-pciback/conf_space.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/drivers/xen/xen-pciback/conf_space.c +++ b/drivers/xen/xen-pciback/conf_space.c @@ -183,8 +183,7 @@ int xen_pcibk_config_read(struct pci_dev field_start = OFFSET(cfg_entry); field_end = OFFSET(cfg_entry) + field->size; - if ((req_start >= field_start && req_start < field_end) - || (req_end > field_start && req_end <= field_end)) { + if (req_end > field_start && field_end > req_start) { err = conf_space_read(dev, cfg_entry, field_start, &tmp_val); if (err) @@ -230,8 +229,7 @@ int xen_pcibk_config_write(struct pci_de field_start = OFFSET(cfg_entry); field_end = OFFSET(cfg_entry) + field->size; - if ((req_start >= field_start && req_start < field_end) - || (req_end > field_start && req_end <= field_end)) { + if (req_end > field_start && field_end > req_start) { tmp_val = 0; err = xen_pcibk_config_read(dev, field_start,