[PATCH v1 2/3] target/loongarch: Allow user enable/disable LSX/LASX features

[Song Gao]

Some users may not need LSX/LASX, this patch allows the user
enable/disable LSX/LASX features.

 e.g
 '-cpu max,lsx=on,lasx=on'   (default);
 '-cpu max,lsx=on,lasx=off'  (enabled LSX);
 '-cpu max,lsx=off,lasx=on'  (error, need lsx=on);
 '-cpu max,lsx=off'          (disable LSX and LASX).

Signed-off-by: Song Gao <gaosong@loongson.cn>
---
 target/loongarch/cpu.c | 64 ++++++++++++++++++++++++++++++++++++++++++
 target/loongarch/cpu.h |  7 +++++
 2 files changed, 71 insertions(+)

diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index ef6922e812..8a47d85d8a 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -478,6 +478,7 @@ static void loongarch_max_initfn(Object *obj)
 {
     /* '-cpu max' for TCG: we use cpu la464. */
     loongarch_la464_initfn(obj);
+    loongarch_cpu_post_init(obj);
 }
 
 static void loongarch_cpu_list_entry(gpointer data, gpointer user_data)
@@ -622,6 +623,69 @@ static const MemoryRegionOps loongarch_qemu_ops = {
 };
 #endif
 
+static bool loongarch_get_lsx(Object *obj, Error **errp)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+
+    if (FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, LSX)) {
+        cpu->has_lsx = true;
+    } else {
+        cpu->has_lsx = false;
+    }
+    return cpu->has_lsx;
+}
+
+static void loongarch_set_lsx(Object *obj, bool value, Error **errp)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+
+    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->has_lsx = value;
+}
+
+static bool loongarch_get_lasx(Object *obj, Error **errp)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+
+    if (FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, LASX)) {
+        cpu->has_lasx = true;
+    } else {
+        cpu->has_lasx = false;
+    }
+    return cpu->has_lasx;
+}
+
+static void loongarch_set_lasx(Object *obj, bool value, Error **errp)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+
+    if (value) {
+        if (!FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, LSX)) {
+            error_setg(errp, "Enabled LASX, need enabled LSX first!");
+            return;
+       }
+        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->has_lasx = value;
+}
+
+void loongarch_cpu_post_init(Object *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);
+}
+
 static void loongarch_cpu_init(Object *obj)
 {
 #ifndef CONFIG_USER_ONLY
diff --git a/target/loongarch/cpu.h b/target/loongarch/cpu.h
index 8b54cf109c..d927377c49 100644
--- a/target/loongarch/cpu.h
+++ b/target/loongarch/cpu.h
@@ -381,6 +381,11 @@ struct ArchCPU {
 
     /* 'compatible' string for this CPU for Linux device trees */
     const char *dtb_compatible;
+
+    /* CPU has LSX */
+    bool has_lsx;
+    /* CPU has  LASX */
+    bool has_lasx;
 };
 
 #define TYPE_LOONGARCH_CPU "loongarch-cpu"
@@ -486,4 +491,6 @@ void loongarch_cpu_list(void);
 #define LOONGARCH_CPU_TYPE_NAME(model) model LOONGARCH_CPU_TYPE_SUFFIX
 #define CPU_RESOLVING_TYPE TYPE_LOONGARCH_CPU
 
+void loongarch_cpu_post_init(Object *obj);
+
 #endif /* LOONGARCH_CPU_H */
-- 
2.25.1