[Qemu-devel] [PATCH RFC 1 3/8] xen/pt: Check if reg->init is past the reg->size

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

It should never happen, but in case it does we want to
report. The code will only write up to reg->size so there
is no runtime danger.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 hw/xen/xen_pt_config_init.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index 91c3a14..bc871c9 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -1901,9 +1901,13 @@ static int xen_pt_config_reg_init(XenPCIPassthroughState *s,
         } else
             val = data;
 
+        if (val & size_mask) {
+            XEN_PT_ERR(&s->dev,"Offset 0x%04x:0x%04u expands past register size(%d)!\n",
+                       offset, val, reg->size);
+        }
         /* This could be just pci_set_long as we don't modify the bits
-         * past reg->size, but in case this routine is run in parallel
-         * we do not want to over-write other registers. */
+         * past reg->size, but in case this routine is run in parallel or the
+         * init value is larger, we do not want to over-write registers. */
         switch (reg->size) {
         case 1: pci_set_byte(s->dev.config + offset, (uint8_t)val); break;
         case 2: pci_set_word(s->dev.config + offset, (uint16_t)val); break;
-- 
2.1.0