target/riscv: move 'vlen' to riscv_cpu_properties[]

Turning 'vlen' into a class property will allow its default value to be
overwritten by cpu_init() later on, solving the issue we have now where
CPU specific settings are getting overwritten by the default.

Common validation bits are moved from riscv_cpu_validate_v() to
prop_vlen_set() to be shared with KVM.

And, as done with every option we migrated to riscv_cpu_properties[],
vendor CPUs can't have their 'vlen' value changed.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Vladimir Isaev <vladimir.isaev@syntacore.com>
Message-ID: <20240105230546.265053-9-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -29,6 +29,7 @@
 #include "qapi/visitor.h"
 #include "qemu/error-report.h"
 #include "hw/qdev-properties.h"
+#include "hw/core/qdev-prop-internal.h"
 #include "migration/vmstate.h"
 #include "fpu/softfloat-helpers.h"
 #include "sysemu/kvm.h"
@@ -1317,6 +1318,7 @@ static void riscv_cpu_init(Object *obj)
 
     /* Default values for non-bool cpu properties */
     cpu->cfg.pmu_mask = MAKE_64BIT_MASK(3, 16);
+    cpu->cfg.vlen = 128;
     cpu->env.vext_ver = VEXT_VERSION_1_00_0;
 }
 
@@ -1788,8 +1790,47 @@ static const PropertyInfo prop_vext_spec = {
     .set = prop_vext_spec_set,
 };
 
+static void prop_vlen_set(Object *obj, Visitor *v, const char *name,
+                         void *opaque, Error **errp)
+{
+    RISCVCPU *cpu = RISCV_CPU(obj);
+    uint16_t value;
+
+    if (!visit_type_uint16(v, name, &value, errp)) {
+        return;
+    }
+
+    if (!is_power_of_2(value)) {
+        error_setg(errp, "Vector extension VLEN must be power of 2");
+        return;
+    }
+
+    if (value != cpu->cfg.vlen && riscv_cpu_is_vendor(obj)) {
+        cpu_set_prop_err(cpu, name, errp);
+        error_append_hint(errp, "Current '%s' val: %u\n",
+                          name, cpu->cfg.vlen);
+        return;
+    }
+
+    cpu_option_add_user_setting(name, value);
+    cpu->cfg.vlen = value;
+}
+
+static void prop_vlen_get(Object *obj, Visitor *v, const char *name,
+                         void *opaque, Error **errp)
+{
+    uint16_t value = RISCV_CPU(obj)->cfg.vlen;
+
+    visit_type_uint16(v, name, &value, errp);
+}
+
+static const PropertyInfo prop_vlen = {
+    .name = "vlen",
+    .get = prop_vlen_get,
+    .set = prop_vlen_set,
+};
+
 Property riscv_cpu_options[] = {
-    DEFINE_PROP_UINT16("vlen", RISCVCPU, cfg.vlen, 128),
     DEFINE_PROP_UINT16("elen", RISCVCPU, cfg.elen, 64),
 
     DEFINE_PROP_UINT16("cbom_blocksize", RISCVCPU, cfg.cbom_blocksize, 64),
@@ -1878,6 +1919,8 @@ static Property riscv_cpu_properties[] = {
     {.name = "priv_spec", .info = &prop_priv_spec},
     {.name = "vext_spec", .info = &prop_vext_spec},
 
+    {.name = "vlen", .info = &prop_vlen},
+
 #ifndef CONFIG_USER_ONLY
     DEFINE_PROP_UINT64("resetvec", RISCVCPU, env.resetvec, DEFAULT_RSTVEC),
 #endif

target/riscv/tcg/tcg-cpu.c

@@ -298,11 +298,6 @@ static void riscv_cpu_validate_misa_mxl(RISCVCPU *cpu, Error **errp)
 static void riscv_cpu_validate_v(CPURISCVState *env, RISCVCPUConfig *cfg,
                                  Error **errp)
 {
-    if (!is_power_of_2(cfg->vlen)) {
-        error_setg(errp, "Vector extension VLEN must be power of 2");
-        return;
-    }
-
     if (cfg->vlen > RV_VLEN_MAX || cfg->vlen < 128) {
         error_setg(errp,
                    "Vector extension implementation only supports VLEN "