[PATCH] hw/arm/smmuv3: Assert input to oas2bits() is valid

[Mostafa Saleh <smostafa@google.com>]

Coverity has spotted a possible problem with the OAS handling
(CID 1558464), where the error return of oas2bits() -1 is not
checked, which can cause an overflow in oas value.

oas2bits() is only called with valid inputs, harden the function
to assert that.

Reported-By: Peter Maydell <peter.maydell@linaro.org>
Link: https://lore.kernel.org/qemu-devel/CAFEAcA-H=n-3mHC+eL6YjfL1m+x+b+Fk3mkgZbN74WNxifFVow@mail.gmail.com/
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 hw/arm/smmuv3-internal.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/arm/smmuv3-internal.h b/hw/arm/smmuv3-internal.h
index 0ebf2eebcf..b6b7399347 100644
--- a/hw/arm/smmuv3-internal.h
+++ b/hw/arm/smmuv3-internal.h
@@ -599,7 +599,8 @@ static inline int oas2bits(int oas_field)
     case 5:
         return 48;
     }
-    return -1;
+
+    g_assert_not_reached();
 }
 
 /* CD fields */
-- 
2.45.2.1089.g2a221341d9-goog