[PATCH RESEND v2 3/6] target/arm/kvm: Add an option to turn on/off el2 support

[Haibo Xu]

Adds an el2=[on/off] option to enable/disable el2(nested virtualization)
support in KVM guest vCPU.

Signed-off-by: Haibo Xu <haibo.xu@linaro.org>
---
 target/arm/cpu.c   | 11 ++++++++++
 target/arm/cpu.h   |  4 ++++
 target/arm/cpu64.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index ae04884408..30cc330f50 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1349,6 +1349,17 @@ void arm_cpu_finalize_features(ARMCPU *cpu, Error **errp)
                 return;
             }
         }
+
+        /*
+         * Currently, vCPU feature 'el2' only supported in KVM mode.
+         */
+        if (kvm_enabled()) {
+            arm_cpu_el2_finalize(cpu, &local_err);
+            if (local_err != NULL) {
+                error_propagate(errp, local_err);
+                return;
+            }
+        }
     }
 
     if (kvm_enabled()) {
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 193a49ec7f..19fa9cfbfd 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -203,10 +203,12 @@ typedef struct {
 # define ARM_MAX_VQ    16
 void arm_cpu_sve_finalize(ARMCPU *cpu, Error **errp);
 void arm_cpu_pauth_finalize(ARMCPU *cpu, Error **errp);
+void arm_cpu_el2_finalize(ARMCPU *cpu, Error **errp);
 #else
 # define ARM_MAX_VQ    1
 static inline void arm_cpu_sve_finalize(ARMCPU *cpu, Error **errp) { }
 static inline void arm_cpu_pauth_finalize(ARMCPU *cpu, Error **errp) { }
+static inline void arm_cpu_el2_finalize(ARMCPU *cpu, Error **errp) { }
 #endif
 
 typedef struct ARMVectorReg {
@@ -1058,6 +1060,7 @@ void aarch64_sve_narrow_vq(CPUARMState *env, unsigned vq);
 void aarch64_sve_change_el(CPUARMState *env, int old_el,
                            int new_el, bool el0_a64);
 void aarch64_add_sve_properties(Object *obj);
+void aarch64_add_el2_properties(Object *obj);
 
 /*
  * SVE registers are encoded in KVM's memory in an endianness-invariant format.
@@ -1089,6 +1092,7 @@ static inline void aarch64_sve_change_el(CPUARMState 
*env, int o,
                                          int n, bool a)
 { }
 static inline void aarch64_add_sve_properties(Object *obj) { }
+static inline void aarch64_add_el2_properties(Object *obj) { }
 #endif
 
 void aarch64_sync_32_to_64(CPUARMState *env);
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index f0a9e968c9..3f3f2c5495 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -603,6 +603,58 @@ static Property arm_cpu_pauth_property =
 static Property arm_cpu_pauth_impdef_property =
     DEFINE_PROP_BOOL("pauth-impdef", ARMCPU, prop_pauth_impdef, false);
 
+void arm_cpu_el2_finalize(ARMCPU *cpu, Error **errp)
+{
+    if (cpu->has_el2) {
+        if (!kvm_enabled() || !kvm_arm_el2_supported()) {
+            error_setg(errp, "'el2' cannot be enabled on this host");
+            return;
+        }
+    }
+
+    if (cpu->has_el2) {
+        set_feature(&cpu->env, ARM_FEATURE_EL2);
+    } else {
+        unset_feature(&cpu->env, ARM_FEATURE_EL2);
+    }
+}
+
+static bool arm_get_el2(Object *obj, Error **errp)
+{
+    ARMCPU *cpu = ARM_CPU(obj);
+
+    return cpu->has_el2;
+}
+
+static void arm_set_el2(Object *obj, bool value, Error **errp)
+{
+    ARMCPU *cpu = ARM_CPU(obj);
+
+    if (value) {
+        if (!kvm_enabled() || !kvm_arm_el2_supported()) {
+            error_setg(errp, "'el2' cannot be enabled on this host");
+            return;
+        }
+        set_feature(&cpu->env, ARM_FEATURE_EL2);
+    } else {
+        unset_feature(&cpu->env, ARM_FEATURE_EL2);
+    }
+
+    cpu->has_el2 = value;
+}
+
+void aarch64_add_el2_properties(Object *obj)
+{
+    /*
+     * vCPU feature 'el2' is only available in KVM mode, and is
+     * disabled by default to keep in line with that in TCG mode.
+     */
+    ARM_CPU(obj)->has_el2 = false;
+    object_property_add_bool(obj, "el2", arm_get_el2, arm_set_el2);
+    object_property_set_description(obj, "el2", "Set off to disable "
+                                    "nested virtulization.");
+}
+
 /* -cpu max: if KVM is enabled, like -cpu host (best possible with this host);
  * otherwise, a CPU with as many features enabled as our emulation supports.
  * The version of '-cpu max' for qemu-system-arm is defined in cpu.c;
-- 
2.17.1