target-arm: Add ARMCPU secure property

Added a "has_el3" state property to the ARMCPU descriptor.  This property
indicates whether the ARMCPU has security extensions enabled (EL3) or not.
By default it is disabled at this time.

Signed-off-by: Greg Bellows <greg.bellows@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

---

v1 -> v2
- Added set of has_el3 to true when EL3 is enabled

v2 -> v3
- Properly init has_el3
- Fixed typo

2 files changed, 25 insertions, 0 deletions

diff --git a/target-arm/cpu-qom.h b/target-arm/cpu-qom.h
index dcfda7dfc..ed5a6441b 100644
--- a/target-arm/cpu-qom.h
+++ b/target-arm/cpu-qom.h
@@ -100,6 +100,8 @@ typedef struct ARMCPU {
     bool start_powered_off;
     /* CPU currently in PSCI powered-off state */
     bool powered_off;
+    /* CPU has security extension */
+    bool has_el3;
 
     /* PSCI conduit used to invoke PSCI methods
      * 0 - disabled, 1 - smc, 2 - hvc
diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index 01afed203..069e09000 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -388,6 +388,9 @@ static Property arm_cpu_reset_hivecs_property =
 static Property arm_cpu_rvbar_property =
             DEFINE_PROP_UINT64("rvbar", ARMCPU, rvbar, 0);
 
+static Property arm_cpu_has_el3_property =
+            DEFINE_PROP_BOOL("has_el3", ARMCPU, has_el3, true);
+
 static void arm_cpu_post_init(Object *obj)
 {
     ARMCPU *cpu = ARM_CPU(obj);
@@ -407,6 +410,14 @@ static void arm_cpu_post_init(Object *obj)
         qdev_property_add_static(DEVICE(obj), &arm_cpu_rvbar_property,
                                  &error_abort);
     }
+
+    if (arm_feature(&cpu->env, ARM_FEATURE_EL3)) {
+        /* Add the has_el3 state CPU property only if EL3 is allowed.  This will
+         * prevent "has_el3" from existing on CPUs which cannot support EL3.
+         */
+        qdev_property_add_static(DEVICE(obj), &arm_cpu_has_el3_property,
+                                 &error_abort);
+    }
 }
 
 static void arm_cpu_finalizefn(Object *obj)
@@ -476,6 +487,18 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
             cpu->reset_sctlr |= (1 << 13);
     }
 
+    if (!cpu->has_el3) {
+        /* If the has_el3 CPU property is disabled then we need to disable the
+         * feature.
+         */
+        unset_feature(env, ARM_FEATURE_EL3);
+
+        /* Disable the security extension feature bits in the processor feature
+         * register as well.  This is id_pfr1[7:4].
+         */
+        cpu->id_pfr1 &= ~0xf0;
+    }
+
     register_cp_regs_for_features(cpu);
     arm_cpu_register_gdb_regs_for_features(cpu);