[PATCH] target/arm: honor HCR_E2H and HCR_TGE in arm_excp_unmasked()

[Ake Koomsin]

An exception targeting EL2 from lower EL is actually maskable when
HCR_E2H and HCR_TGE are both set. This applies to both secure and
non-secure Security state.

Signed-off-by: Ake Koomsin <ake@igel.co.jp>
---
 target/arm/cpu.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 94ca6f163f..86d3377d3f 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -561,14 +561,24 @@ static inline bool arm_excp_unmasked(CPUState *cs, 
unsigned int excp_idx,
     if ((target_el > cur_el) && (target_el != 1)) {
         /* Exceptions targeting a higher EL may not be maskable */
         if (arm_feature(env, ARM_FEATURE_AARCH64)) {
-            /*
-             * 64-bit masking rules are simple: exceptions to EL3
-             * can't be masked, and exceptions to EL2 can only be
-             * masked from Secure state. The HCR and SCR settings
-             * don't affect the masking logic, only the interrupt routing.
-             */
-            if (target_el == 3 || !secure || (env->cp15.scr_el3 & SCR_EEL2)) {
+            switch (target_el) {
+            case 2:
+                /*
+                 * According to ARM DDI 0487H.a, an interrupt can be masked
+                 * when HCR_E2H and HCR_TGE are both set regardless of the
+                 * current Security state. Note that We need to revisit this
+                 * part again once we need to support NMI.
+                 */
+                if ((hcr_el2 & (HCR_E2H | HCR_TGE)) != (HCR_E2H | HCR_TGE)) {
+                        unmasked = true;
+                }
+                break;
+            case 3:
+                /* Interrupt cannot be masked when the target EL is 3 */
                 unmasked = true;
+                break;
+            default:
+                g_assert_not_reached();
             }
         } else {
             /*
-- 
2.25.1