[PULL,1/6] target/loongarch: Add loongson binary translation feature

diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index 7212fb5f8f..29577e6b71 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -664,12 +664,36 @@  static void loongarch_set_lasx(Object *obj, bool value, Error **errp)
     }
 }
 
+static bool loongarch_get_lbt(Object *obj, Error **errp)
+{
+    return LOONGARCH_CPU(obj)->lbt != ON_OFF_AUTO_OFF;
+}
+
+static void loongarch_set_lbt(Object *obj, bool value, Error **errp)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+
+    cpu->lbt = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
+}
+
 void loongarch_cpu_post_init(Object *obj)
 {
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+
     object_property_add_bool(obj, "lsx", loongarch_get_lsx,
                              loongarch_set_lsx);
     object_property_add_bool(obj, "lasx", loongarch_get_lasx,
                              loongarch_set_lasx);
+    /* lbt is enabled only in kvm mode, not supported in tcg mode */
+    if (kvm_enabled()) {
+        cpu->lbt = ON_OFF_AUTO_AUTO;
+        object_property_add_bool(obj, "lbt", loongarch_get_lbt,
+                                 loongarch_set_lbt);
+        object_property_set_description(obj, "lbt",
+                                   "Set off to disable Binary Tranlation.");
+    } else {
+        cpu->lbt = ON_OFF_AUTO_OFF;
+    }
 }
 
 static void loongarch_cpu_init(Object *obj)
diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
index 6c41fafb70..2b3f2758f6 100644
--- a/target/loongarch/cpu.h
+++ b/target/loongarch/cpu.h
@@ -153,6 +153,7 @@  FIELD(CPUCFG2, LLFTP_VER, 15, 3)
 FIELD(CPUCFG2, LBT_X86, 18, 1)
 FIELD(CPUCFG2, LBT_ARM, 19, 1)
 FIELD(CPUCFG2, LBT_MIPS, 20, 1)
+FIELD(CPUCFG2, LBT_ALL, 18, 3)
 FIELD(CPUCFG2, LSPW, 21, 1)
 FIELD(CPUCFG2, LAM, 22, 1)
 
@@ -281,6 +282,10 @@  struct LoongArchTLB {
 typedef struct LoongArchTLB LoongArchTLB;
 #endif
 
+enum loongarch_features {
+    LOONGARCH_FEATURE_LBT, /* loongson binary translation extension */
+};
+
 typedef struct CPUArchState {
     uint64_t gpr[32];
     uint64_t pc;
@@ -381,6 +386,7 @@  struct ArchCPU {
     CPULoongArchState env;
     QEMUTimer timer;
     uint32_t  phy_id;
+    OnOffAuto lbt;
 
     /* 'compatible' string for this CPU for Linux device trees */
     const char *dtb_compatible;
diff --git a/target/loongarch/kvm/kvm.c b/target/loongarch/kvm/kvm.c
index 30ec16025d..079f8ca5d7 100644
--- a/target/loongarch/kvm/kvm.c
+++ b/target/loongarch/kvm/kvm.c
@@ -9,6 +9,7 @@ 
 #include <sys/ioctl.h>
 #include <linux/kvm.h>
 
+#include "qapi/error.h"
 #include "qemu/timer.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
@@ -666,17 +667,71 @@  static void kvm_loongarch_vm_stage_change(void *opaque, bool running,
     }
 }
 
+static bool kvm_feature_supported(CPUState *cs, enum loongarch_features feature)
+{
+    int ret;
+    struct kvm_device_attr attr;
+
+    switch (feature) {
+    case LOONGARCH_FEATURE_LBT:
+        /*
+         * Return all if all the LBT features are supported such as:
+         *  KVM_LOONGARCH_VM_FEAT_X86BT
+         *  KVM_LOONGARCH_VM_FEAT_ARMBT
+         *  KVM_LOONGARCH_VM_FEAT_MIPSBT
+         */
+        attr.group = KVM_LOONGARCH_VM_FEAT_CTRL;
+        attr.attr = KVM_LOONGARCH_VM_FEAT_X86BT;
+        ret = kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        attr.attr = KVM_LOONGARCH_VM_FEAT_ARMBT;
+        ret |= kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        attr.attr = KVM_LOONGARCH_VM_FEAT_MIPSBT;
+        ret |= kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        return (ret == 0);
+    default:
+        return false;
+    }
+}
+
+static int kvm_cpu_check_lbt(CPUState *cs, Error **errp)
+{
+    CPULoongArchState *env = cpu_env(cs);
+    LoongArchCPU *cpu = LOONGARCH_CPU(cs);
+    bool kvm_supported;
+
+    kvm_supported = kvm_feature_supported(cs, LOONGARCH_FEATURE_LBT);
+    if (cpu->lbt == ON_OFF_AUTO_ON) {
+        if (kvm_supported) {
+            env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LBT_ALL, 7);
+        } else {
+            error_setg(errp, "'lbt' feature not supported by KVM on this host");
+            return -ENOTSUP;
+        }
+    } else if ((cpu->lbt == ON_OFF_AUTO_AUTO) && kvm_supported) {
+        env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LBT_ALL, 7);
+    }
+
+    return 0;
+}
+
 int kvm_arch_init_vcpu(CPUState *cs)
 {
     uint64_t val;
+    int ret;
+    Error *local_err = NULL;
 
+    ret = 0;
     qemu_add_vm_change_state_handler(kvm_loongarch_vm_stage_change, cs);
 
     if (!kvm_get_one_reg(cs, KVM_REG_LOONGARCH_DEBUG_INST, &val)) {
         brk_insn = val;
     }
 
-    return 0;
+    ret = kvm_cpu_check_lbt(cs, &local_err);
+    if (ret < 0) {
+        error_report_err(local_err);
+    }
+    return ret;
 }
 
 int kvm_arch_destroy_vcpu(CPUState *cs)
diff --git a/target/loongarch/loongarch-qmp-cmds.c b/target/loongarch/loongarch-qmp-cmds.c
index 8721a5eb13..c6f6e1ef85 100644
--- a/target/loongarch/loongarch-qmp-cmds.c
+++ b/target/loongarch/loongarch-qmp-cmds.c
@@ -40,7 +40,7 @@  CpuDefinitionInfoList *qmp_query_cpu_definitions(Error **errp)
 }
 
 static const char *cpu_model_advertised_features[] = {
-    "lsx", "lasx", NULL
+    "lsx", "lasx", "lbt", NULL
 };
 
 CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type,