[Xen-devel] [PATCH v2 for-4.11 2/2] vpci: make sure handlers can deal with size == 0

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

The code is not prepared to handle such case, so just return early. In
the debug case add an assert.

Reported-by: Coverity
Coverity ID: 1430809
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/drivers/vpci/vpci.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index 2913b56500..82607bdb9a 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -320,6 +320,12 @@ uint32_t vpci_read(pci_sbdf_t sbdf, unsigned int reg, 
unsigned int size)
     unsigned int data_offset = 0;
     uint32_t data = ~(uint32_t)0;
 
+    if ( !size )
+    {
+        ASSERT_UNREACHABLE();
+        return data;
+    }
+
     /* Find the PCI dev matching the address. */
     pdev = pci_get_pdev_by_domain(d, sbdf.seg, sbdf.bus, sbdf.extfunc);
     if ( !pdev )
@@ -416,6 +422,12 @@ void vpci_write(pci_sbdf_t sbdf, unsigned int reg, 
unsigned int size,
     const struct vpci_register *r;
     unsigned int data_offset = 0;
 
+    if ( !size )
+    {
+        ASSERT_UNREACHABLE();
+        return;
+    }
+
     /*
      * Find the PCI dev matching the address.
      * Passthrough everything that's not trapped.
-- 
2.16.2


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