Like LBT feature, add type OnOffAuto for LSX feature setting. Also
add LSX feature detection with new VM ioctl command, fallback to old
method if it is not supported.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 target/loongarch/cpu.c     | 38 +++++++++++++++------------
 target/loongarch/cpu.h     |  2 ++
 target/loongarch/kvm/kvm.c | 54 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+), 17 deletions(-)

diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index 57cc4f314b..09dc923f45 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -378,6 +378,7 @@ static void loongarch_la464_initfn(Object *obj)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
     CPULoongArchState *env = &cpu->env;
+    uint32_t data = 0;
     int i;
 
     for (i = 0; i < 21; i++) {
@@ -387,7 +388,6 @@ static void loongarch_la464_initfn(Object *obj)
     cpu->dtb_compatible = "loongarch,Loongson-3A5000";
     env->cpucfg[0] = 0x14c010;  /* PRID */
 
-    uint32_t data = 0;
     data = FIELD_DP32(data, CPUCFG1, ARCH, 2);
     data = FIELD_DP32(data, CPUCFG1, PGMMU, 1);
     data = FIELD_DP32(data, CPUCFG1, IOCSR, 1);
@@ -476,7 +476,7 @@ static void loongarch_la132_initfn(Object *obj)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
     CPULoongArchState *env = &cpu->env;
-
+    uint32_t data = 0;
     int i;
 
     for (i = 0; i < 21; i++) {
@@ -486,7 +486,6 @@ static void loongarch_la132_initfn(Object *obj)
     cpu->dtb_compatible = "loongarch,Loongson-1C103";
     env->cpucfg[0] = 0x148042;  /* PRID */
 
-    uint32_t data = 0;
     data = FIELD_DP32(data, CPUCFG1, ARCH, 1); /* LA32 */
     data = FIELD_DP32(data, CPUCFG1, PGMMU, 1);
     data = FIELD_DP32(data, CPUCFG1, IOCSR, 1);
@@ -614,27 +613,30 @@ static void loongarch_cpu_realizefn(DeviceState *dev, Error **errp)
 
 static bool loongarch_get_lsx(Object *obj, Error **errp)
 {
-    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
-    bool ret;
-
-    if (FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, LSX)) {
-        ret = true;
-    } else {
-        ret = false;
-    }
-    return ret;
+    return LOONGARCH_CPU(obj)->lsx != ON_OFF_AUTO_OFF;
 }
 
 static void loongarch_set_lsx(Object *obj, bool value, Error **errp)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+    uint32_t val;
 
-    if (value) {
-        cpu->env.cpucfg[2] = FIELD_DP32(cpu->env.cpucfg[2], CPUCFG2, LSX, 1);
-    } else {
-        cpu->env.cpucfg[2] = FIELD_DP32(cpu->env.cpucfg[2], CPUCFG2, LSX, 0);
-        cpu->env.cpucfg[2] = FIELD_DP32(cpu->env.cpucfg[2], CPUCFG2, LASX, 0);
+    cpu->lsx = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
+    if (kvm_enabled()) {
+        /* kvm feature detection in function kvm_arch_init_vcpu */
+        return;
     }
+
+    /* LSX feature detection in TCG mode */
+    val = cpu->env.cpucfg[2];
+    if (cpu->lsx == ON_OFF_AUTO_ON) {
+        if (FIELD_EX32(val, CPUCFG2, LSX) == 0) {
+            error_setg(errp, "Failed to enable LSX in TCG mode");
+            return;
+        }
+    }
+
+    cpu->env.cpucfg[2] = FIELD_DP32(val, CPUCFG2, LSX, value);
 }
 
 static bool loongarch_get_lasx(Object *obj, Error **errp)
@@ -692,6 +694,7 @@ void loongarch_cpu_post_init(Object *obj)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
 
+    cpu->lsx = ON_OFF_AUTO_AUTO;
     object_property_add_bool(obj, "lsx", loongarch_get_lsx,
                              loongarch_set_lsx);
     object_property_add_bool(obj, "lasx", loongarch_get_lasx,
@@ -712,6 +715,7 @@ void loongarch_cpu_post_init(Object *obj)
 
     } else {
         cpu->lbt = ON_OFF_AUTO_OFF;
+        cpu->pmu = ON_OFF_AUTO_OFF;
     }
 }
 
diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
index 86c86c6c95..5bddf72c22 100644
--- a/target/loongarch/cpu.h
+++ b/target/loongarch/cpu.h
@@ -283,6 +283,7 @@ typedef struct LoongArchTLB LoongArchTLB;
 #endif
 
 enum loongarch_features {
+    LOONGARCH_FEATURE_LSX,
     LOONGARCH_FEATURE_LBT, /* loongson binary translation extension */
     LOONGARCH_FEATURE_PMU,
 };
@@ -404,6 +405,7 @@ struct ArchCPU {
     uint32_t  phy_id;
     OnOffAuto lbt;
     OnOffAuto pmu;
+    OnOffAuto lsx;
 
     /* '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 ff81806ca3..390828ef78 100644
--- a/target/loongarch/kvm/kvm.c
+++ b/target/loongarch/kvm/kvm.c
@@ -798,8 +798,35 @@ static bool kvm_feature_supported(CPUState *cs, enum loongarch_features feature)
 {
     int ret;
     struct kvm_device_attr attr;
+    uint64_t val;
 
     switch (feature) {
+    case LOONGARCH_FEATURE_LSX:
+        attr.group = KVM_LOONGARCH_VM_FEAT_CTRL;
+        attr.attr = KVM_LOONGARCH_VM_FEAT_LSX;
+        ret = kvm_vm_ioctl(kvm_state, KVM_HAS_DEVICE_ATTR, &attr);
+        if (ret == 0) {
+            return true;
+        }
+
+        /* Fallback to old kernel detect interface */
+        val = 0;
+        attr.group = KVM_LOONGARCH_VCPU_CPUCFG;
+        /* Cpucfg2 */
+        attr.attr  = 2;
+        attr.addr = (uint64_t)&val;
+        ret = kvm_vcpu_ioctl(cs, KVM_HAS_DEVICE_ATTR, &attr);
+        if (!ret) {
+            ret = kvm_vcpu_ioctl(cs, KVM_GET_DEVICE_ATTR, &attr);
+            if (ret) {
+                return false;
+            }
+
+            ret = FIELD_EX32((uint32_t)val, CPUCFG2, LSX);
+            return (ret != 0);
+        }
+        return false;
+
     case LOONGARCH_FEATURE_LBT:
         /*
          * Return all if all the LBT features are supported such as:
@@ -829,6 +856,28 @@ static bool kvm_feature_supported(CPUState *cs, enum loongarch_features feature)
     return false;
 }
 
+static int kvm_cpu_check_lsx(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_LSX);
+    env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LSX, 0);
+    if (cpu->lsx == ON_OFF_AUTO_ON) {
+        if (kvm_supported) {
+            env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LSX, 1);
+        } else {
+            error_setg(errp, "'lsx' feature not supported by KVM on this host");
+            return -ENOTSUP;
+        }
+    } else if ((cpu->lsx == ON_OFF_AUTO_AUTO) && kvm_supported) {
+        env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LSX, 1);
+    }
+
+    return 0;
+}
+
 static int kvm_cpu_check_lbt(CPUState *cs, Error **errp)
 {
     CPULoongArchState *env = cpu_env(cs);
@@ -889,6 +938,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
         brk_insn = val;
     }
 
+    ret = kvm_cpu_check_lsx(cs, &local_err);
+    if (ret < 0) {
+        error_report_err(local_err);
+    }
+
     ret = kvm_cpu_check_lbt(cs, &local_err);
     if (ret < 0) {
         error_report_err(local_err);
-- 
2.39.3