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Commit 02ef871e authored by Andrey Grodzovsky's avatar Andrey Grodzovsky Committed by David Vrabel
Browse files

xen/pciback: Fix conf_space read/write overlap check. 



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: default avatarAndrey Grodzovsky <andrey2805@gmail.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: default avatarJan Beulich <JBeulich@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent 1cf38741

drivers/xen/xen-pciback/conf_space.c

+2 −4
Original line number Original line Diff line number Diff line
@@ -183,8 +183,7 @@ int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size, 
		field_start = OFFSET(cfg_entry);

		field_start = OFFSET(cfg_entry);

		field_end = OFFSET(cfg_entry) + field->size;

		field_end = OFFSET(cfg_entry) + field->size;





		if ((req_start >= field_start && req_start < field_end)

		 if (req_end > field_start && field_end > req_start) {

		    || (req_end > field_start && req_end <= field_end)) {

			err = conf_space_read(dev, cfg_entry, field_start,

			err = conf_space_read(dev, cfg_entry, field_start,

					      &tmp_val);

					      &tmp_val);

			if (err)

			if (err)
@@ -230,8 +229,7 @@ int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value) 
		field_start = OFFSET(cfg_entry);

		field_start = OFFSET(cfg_entry);

		field_end = OFFSET(cfg_entry) + field->size;

		field_end = OFFSET(cfg_entry) + field->size;





		if ((req_start >= field_start && req_start < field_end)

		 if (req_end > field_start && field_end > req_start) {

		    || (req_end > field_start && req_end <= field_end)) {

			tmp_val = 0;

			tmp_val = 0;





			err = xen_pcibk_config_read(dev, field_start,

			err = xen_pcibk_config_read(dev, field_start,