target/arm: Restrict system register properties to system binary

Do not expose the following system-specific properties on user-mode
binaries:

 - psci-conduit
 - cntfrq (ARM_FEATURE_GENERIC_TIMER)
 - rvbar (ARM_FEATURE_V8)
 - has-mpu (ARM_FEATURE_PMSA)
 - pmsav7-dregion (ARM_FEATURE_PMSA)
 - reset-cbar (ARM_FEATURE_CBAR)
 - reset-hivecs (ARM_FEATURE_M)
 - init-nsvtor (ARM_FEATURE_M)
 - init-svtor (ARM_FEATURE_M_SECURITY)
 - idau (ARM_FEATURE_M_SECURITY)

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250623121845.7214-13-philmd@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/cpu.c

@@ -1500,6 +1500,7 @@ static void arm_cpu_initfn(Object *obj)
  * 0 means "unset, use the default value". That default might vary depending
  * on the CPU type, and is set in the realize fn.
  */
+#ifndef CONFIG_USER_ONLY
 static const Property arm_cpu_gt_cntfrq_property =
             DEFINE_PROP_UINT64("cntfrq", ARMCPU, gt_cntfrq_hz, 0);
 
@@ -1509,7 +1510,6 @@ static const Property arm_cpu_reset_cbar_property =
 static const Property arm_cpu_reset_hivecs_property =
             DEFINE_PROP_BOOL("reset-hivecs", ARMCPU, reset_hivecs, false);
 
-#ifndef CONFIG_USER_ONLY
 static const Property arm_cpu_has_el2_property =
             DEFINE_PROP_BOOL("has_el2", ARMCPU, has_el2, true);
 
@@ -1532,6 +1532,7 @@ static const Property arm_cpu_has_neon_property =
 static const Property arm_cpu_has_dsp_property =
             DEFINE_PROP_BOOL("dsp", ARMCPU, has_dsp, true);
 
+#ifndef CONFIG_USER_ONLY
 static const Property arm_cpu_has_mpu_property =
             DEFINE_PROP_BOOL("has-mpu", ARMCPU, has_mpu, true);
 
@@ -1544,6 +1545,7 @@ static const Property arm_cpu_pmsav7_dregion_property =
             DEFINE_PROP_UNSIGNED_NODEFAULT("pmsav7-dregion", ARMCPU,
                                            pmsav7_dregion,
                                            qdev_prop_uint32, uint32_t);
+#endif
 
 static bool arm_get_pmu(Object *obj, Error **errp)
 {
@@ -1731,6 +1733,7 @@ static void arm_cpu_post_init(Object *obj)
                                         "Set on/off to enable/disable aarch64 "
                                         "execution state ");
     }
+#ifndef CONFIG_USER_ONLY
     if (arm_feature(&cpu->env, ARM_FEATURE_CBAR) ||
         arm_feature(&cpu->env, ARM_FEATURE_CBAR_RO)) {
         qdev_property_add_static(DEVICE(obj), &arm_cpu_reset_cbar_property);
@@ -1746,7 +1749,6 @@ static void arm_cpu_post_init(Object *obj)
                                        OBJ_PROP_FLAG_READWRITE);
     }
 
-#ifndef CONFIG_USER_ONLY
     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.
@@ -1818,6 +1820,7 @@ static void arm_cpu_post_init(Object *obj)
         qdev_property_add_static(DEVICE(obj), &arm_cpu_has_dsp_property);
     }
 
+#ifndef CONFIG_USER_ONLY
     if (arm_feature(&cpu->env, ARM_FEATURE_PMSA)) {
         qdev_property_add_static(DEVICE(obj), &arm_cpu_has_mpu_property);
         if (arm_feature(&cpu->env, ARM_FEATURE_V7)) {
@@ -1854,8 +1857,6 @@ static void arm_cpu_post_init(Object *obj)
                                    &cpu->psci_conduit,
                                    OBJ_PROP_FLAG_READWRITE);
 
-    qdev_property_add_static(DEVICE(obj), &arm_cpu_cfgend_property);
-
     if (arm_feature(&cpu->env, ARM_FEATURE_GENERIC_TIMER)) {
         qdev_property_add_static(DEVICE(cpu), &arm_cpu_gt_cntfrq_property);
     }
@@ -1864,7 +1865,6 @@ static void arm_cpu_post_init(Object *obj)
         kvm_arm_add_vcpu_properties(cpu);
     }
 
-#ifndef CONFIG_USER_ONLY
     if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64) &&
         cpu_isar_feature(aa64_mte, cpu)) {
         object_property_add_link(obj, "tag-memory",
@@ -1882,6 +1882,7 @@ static void arm_cpu_post_init(Object *obj)
         }
     }
 #endif
+    qdev_property_add_static(DEVICE(obj), &arm_cpu_cfgend_property);
 }
 
 static void arm_cpu_finalizefn(Object *obj)