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* [PATCH] xen/pciback: Fix conf_space read/write overlap check.
@ 2016-06-21 14:37 Andrey Grodzovsky
  2016-06-21 15:52 ` Boris Ostrovsky
  2016-06-21 17:15 ` [Xen-devel] " David Vrabel
  0 siblings, 2 replies; 6+ messages in thread
From: Andrey Grodzovsky @ 2016-06-21 14:37 UTC (permalink / raw)
  To: xen-devel; +Cc: jw, Andrey Grodzovsky, Jan Beulich, Boris Ostrovsky, stable

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.

Related to https://www.mail-archive.com/xen-devel@lists.xen.org/msg72174.html

Cc: Jan Beulich <JBeulich@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Andrey Grodzovsky <andrey2805@gmail.com>
---
 drivers/xen/xen-pciback/conf_space.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/xen-pciback/conf_space.c b/drivers/xen/xen-pciback/conf_space.c
index 8e67336..6a25533 100644
--- 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 *dev, int offset, int size,
 		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_dev *dev, int offset, int size, u32 value)
 		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,
-- 
2.1.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH] xen/pciback: Fix conf_space read/write overlap check.
@ 2016-06-21 18:26 Andrey Grodzovsky
  2016-06-22  6:49 ` Jan Beulich
  0 siblings, 1 reply; 6+ messages in thread
From: Andrey Grodzovsky @ 2016-06-21 18:26 UTC (permalink / raw)
  To: xen-devel
  Cc: david.vrabel, jw, Andrey Grodzovsky, Jan Beulich, Boris Ostrovsky,
	stable

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 LATENCY_TIMER field
(offset == 0xd, length == 1) is fully contained in the write request
and hence is excluded from write, which is incorrect.

Related to https://www.mail-archive.com/xen-devel@lists.xen.org/msg72174.html

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Andrey Grodzovsky <andrey2805@gmail.com>
---
 drivers/xen/xen-pciback/conf_space.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/xen-pciback/conf_space.c b/drivers/xen/xen-pciback/conf_space.c
index 8e67336..6a25533 100644
--- 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 *dev, int offset, int size,
 		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_dev *dev, int offset, int size, u32 value)
 		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,
-- 
2.1.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2016-06-22  7:10 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2016-06-21 14:37 [PATCH] xen/pciback: Fix conf_space read/write overlap check Andrey Grodzovsky
2016-06-21 15:52 ` Boris Ostrovsky
2016-06-22  4:11   ` Juergen Gross
2016-06-21 17:15 ` [Xen-devel] " David Vrabel
  -- strict thread matches above, loose matches on Subject: below --
2016-06-21 18:26 Andrey Grodzovsky
2016-06-22  6:49 ` Jan Beulich

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