target/loongarch: Use auto method with LASX feature

Like LSX feature, add type OnOffAuto for LASX feature setting.

Signed-off-by: Bibo Mao <[email protected]>
Reviewed-by: Bibo Mao <[email protected]>

Author: bibo-mao

target/loongarch/cpu.c

@@ -623,6 +623,14 @@ static void loongarch_set_lsx(Object *obj, bool value, Error **errp)
     uint32_t val;
 
     cpu->lsx = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
+    if (cpu->lsx == ON_OFF_AUTO_OFF) {
+        cpu->lasx = ON_OFF_AUTO_OFF;
+        if (cpu->lasx == ON_OFF_AUTO_ON) {
+            error_setg(errp, "Failed to disable LSX since LASX is enabled");
+            return;
+        }
+    }
+
     if (kvm_enabled()) {
         /* kvm feature detection in function kvm_arch_init_vcpu */
         return;
@@ -635,36 +643,45 @@ static void loongarch_set_lsx(Object *obj, bool value, Error **errp)
             error_setg(errp, "Failed to enable LSX in TCG mode");
             return;
         }
+    } else {
+        cpu->env.cpucfg[2] = FIELD_DP32(val, CPUCFG2, LASX, 0);
+        val = cpu->env.cpucfg[2];
     }
 
     cpu->env.cpucfg[2] = FIELD_DP32(val, CPUCFG2, LSX, value);
 }
 
 static bool loongarch_get_lasx(Object *obj, Error **errp)
 {
-    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
-    bool ret;
-
-    if (FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, LASX)) {
-        ret = true;
-    } else {
-        ret = false;
-    }
-    return ret;
+    return LOONGARCH_CPU(obj)->lasx != ON_OFF_AUTO_OFF;
 }
 
 static void loongarch_set_lasx(Object *obj, bool value, Error **errp)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+    uint32_t val;
 
-    if (value) {
-	if (!FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, LSX)) {
-            cpu->env.cpucfg[2] = FIELD_DP32(cpu->env.cpucfg[2], CPUCFG2, LSX, 1);
-	}
-        cpu->env.cpucfg[2] = FIELD_DP32(cpu->env.cpucfg[2], CPUCFG2, LASX, 1);
-    } else {
-        cpu->env.cpucfg[2] = FIELD_DP32(cpu->env.cpucfg[2], CPUCFG2, LASX, 0);
+    cpu->lasx = value ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
+    if ((cpu->lsx == ON_OFF_AUTO_OFF) && (cpu->lasx == ON_OFF_AUTO_ON)) {
+        error_setg(errp, "Failed to enable LASX since lSX is disabled");
+        return;
+    }
+
+    if (kvm_enabled()) {
+        /* kvm feature detection in function kvm_arch_init_vcpu */
+        return;
     }
+
+    /* LASX feature detection in TCG mode */
+    val = cpu->env.cpucfg[2];
+    if (cpu->lasx == ON_OFF_AUTO_ON) {
+        if (FIELD_EX32(val, CPUCFG2, LASX) == 0) {
+            error_setg(errp, "Failed to enable LASX in TCG mode");
+            return;
+        }
+    }
+
+    cpu->env.cpucfg[2] = FIELD_DP32(val, CPUCFG2, LASX, value);
 }
 
 static bool loongarch_get_lbt(Object *obj, Error **errp)
@@ -696,6 +713,7 @@ void loongarch_cpu_post_init(Object *obj)
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
 
     cpu->lsx = ON_OFF_AUTO_AUTO;
+    cpu->lasx = 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,

target/loongarch/cpu.h

@@ -284,6 +284,7 @@ typedef struct LoongArchTLB LoongArchTLB;
 
 enum loongarch_features {
     LOONGARCH_FEATURE_LSX,
+    LOONGARCH_FEATURE_LASX,
     LOONGARCH_FEATURE_LBT, /* loongson binary translation extension */
     LOONGARCH_FEATURE_PMU,
 };
@@ -406,6 +407,7 @@ struct ArchCPU {
     OnOffAuto lbt;
     OnOffAuto pmu;
     OnOffAuto lsx;
+    OnOffAuto lasx;
 
     /* 'compatible' string for this CPU for Linux device trees */
     const char *dtb_compatible;

target/loongarch/kvm/kvm.c

@@ -827,6 +827,32 @@ static bool kvm_feature_supported(CPUState *cs, enum loongarch_features feature)
         }
         return false;
 
+    case LOONGARCH_FEATURE_LASX:
+        attr.group = KVM_LOONGARCH_VM_FEAT_CTRL;
+        attr.attr = KVM_LOONGARCH_VM_FEAT_LASX;
+        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, LASX);
+            return (ret != 0);
+        }
+        return false;
+
     case LOONGARCH_FEATURE_LBT:
         /*
          * Return all if all the LBT features are supported such as:
@@ -878,6 +904,28 @@ static int kvm_cpu_check_lsx(CPUState *cs, Error **errp)
     return 0;
 }
 
+static int kvm_cpu_check_lasx(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_LASX);
+    env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LASX, 0);
+    if (cpu->lasx == ON_OFF_AUTO_ON) {
+        if (kvm_supported) {
+            env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LASX, 1);
+        } else {
+            error_setg(errp, "'lasx' feature not supported by KVM on host");
+            return -ENOTSUP;
+        }
+    } else if ((cpu->lasx == ON_OFF_AUTO_AUTO) && kvm_supported) {
+        env->cpucfg[2] = FIELD_DP32(env->cpucfg[2], CPUCFG2, LASX, 1);
+    }
+
+    return 0;
+}
+
 static int kvm_cpu_check_lbt(CPUState *cs, Error **errp)
 {
     CPULoongArchState *env = cpu_env(cs);
@@ -943,6 +991,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
         error_report_err(local_err);
     }
 
+    ret = kvm_cpu_check_lasx(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);