[Qemu-devel] [PATCH v3 15/22] target-arm: A64: Forbid ERET to unimplemented ELs

[Edgar E. Iglesias]

From: "Edgar E. Iglesias" <address@hidden>

Check for EL2 support before returning to it.

Reviewed-by: Peter Crosthwaite <address@hidden>
Signed-off-by: Edgar E. Iglesias <address@hidden>
---
 target-arm/op_helper.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
index a6eedb2..d89755a 100644
--- a/target-arm/op_helper.c
+++ b/target-arm/op_helper.c
@@ -411,12 +411,11 @@ void HELPER(exception_return)(CPUARMState *env)
         env->regs[15] = env->elr_el[1] & ~0x1;
     } else {
         new_el = extract32(spsr, 2, 2);
-        if (new_el > cur_el) {
-            /* Disallow returns to higher ELs than the current one.  */
-            goto illegal_return;
-        }
-        if (new_el > 1) {
-            /* Return to unimplemented EL */
+        if (new_el > cur_el
+            || (new_el == 2 && !arm_feature(env, ARM_FEATURE_EL2))) {
+            /* Disallow return to an EL which is unimplemented or higher
+             * than the current one.
+             */
             goto illegal_return;
         }
         if (extract32(spsr, 1, 1)) {
-- 
1.8.3.2