| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.6 27/96] xen/pciback: Fix conf_space read/write overlap check. | Date | Mon, 8 Aug 2016 21:10:50 +0200 |
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4.6-stable review patch. If anyone has any objections, please let me know.
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From: Andrey Grodzovsky <andrey2805@gmail.com>
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 <andrey2805@gmail.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Jan Beulich <JBeulich@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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,
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