[RFC 6/9] target/arm: introduce KVM_CAP_ARM_CPU_FEATURE

[Peng Liang]

Introduce KVM_CAP_ARM_CPU_FEATURE to check whether KVM supports to set
CPU features in ARM.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Peng Liang <liangpeng10@huawei.com>
---
 linux-headers/linux/kvm.h |  1 +
 target/arm/cpu.c          |  5 +++++
 target/arm/kvm64.c        | 14 ++++++++++++++
 target/arm/kvm_arm.h      |  7 +++++++
 4 files changed, 27 insertions(+)

diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index a28c366737..0b83d2b4bb 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -1031,6 +1031,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_PPC_SECURE_GUEST 181
 #define KVM_CAP_HALT_POLL 182
 #define KVM_CAP_ASYNC_PF_INT 183
+#define KVM_CAP_ARM_CPU_FEATURE 187
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 4e67b8f22c..3fc54cb3a4 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1539,6 +1539,11 @@ static void arm_cpu_set_bit_prop(Object *obj, Visitor 
*v, const char *name,
     Error *local_err = NULL;
     bool value;
 
+    if (!kvm_arm_cpu_feature_supported()) {
+        warn_report("KVM doesn't support to set CPU feature in arm.  "
+                    "Setting to `%s` is ignored.", name);
+        return;
+    }
     if (dev->realized) {
         qdev_prop_set_after_realize(dev, name, errp);
         return;
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index be2d0cda0d..e7470477d5 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -664,6 +664,20 @@ bool kvm_arm_sve_supported(void)
     return kvm_check_extension(kvm_state, KVM_CAP_ARM_SVE);
 }
 
+bool kvm_arm_cpu_feature_supported(void)
+{
+    static bool cpu_feature_initialized;
+    static bool cpu_feature_supported;
+
+    if (!cpu_feature_initialized) {
+        cpu_feature_supported = kvm_check_extension(kvm_state,
+                                                    KVM_CAP_ARM_CPU_FEATURE);
+        cpu_feature_initialized = true;
+    }
+
+    return cpu_feature_supported;
+}
+
 QEMU_BUILD_BUG_ON(KVM_ARM64_SVE_VQ_MIN != 1);
 
 void kvm_arm_sve_get_vls(CPUState *cs, unsigned long *map)
diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index 99035494ae..c2481ce464 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -290,6 +290,13 @@ bool kvm_arm_pmu_supported(void);
  */
 bool kvm_arm_sve_supported(void);
 
+/**
+ * kvm_arm_cpu_feature_supported:
+ *
+ * Returns true if KVM can set CPU features and false otherwise.
+ */
+bool kvm_arm_cpu_feature_supported(void);
+
 /**
  * kvm_arm_get_max_vm_ipa_size:
  * @ms: Machine state handle
-- 
2.18.4