target/riscv/cpu.c: add priv_spec validate/disable_exts helpers

We're doing env->priv_spec validation and assignment at the start of
riscv_cpu_realize(), which is fine, but then we're doing a force disable
on extensions that aren't compatible with the priv version.

This second step is being done too early. The disabled extensions might be
re-enabled again in riscv_cpu_validate_set_extensions() by accident. A
better place to put this code is at the end of
riscv_cpu_validate_set_extensions() after all the validations are
completed.

Add a new helper, riscv_cpu_disable_priv_spec_isa_exts(), to disable the
extesions after the validation is done. While we're at it, create a
riscv_cpu_validate_priv_spec() helper to host all env->priv_spec related
validation to unclog riscv_cpu_realize a bit.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230517135714.211809-8-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -864,6 +864,52 @@ static void riscv_cpu_validate_v(CPURISCVState *env, RISCVCPUConfig *cfg,
     env->vext_ver = vext_version;
 }
 
+static void riscv_cpu_validate_priv_spec(RISCVCPU *cpu, Error **errp)
+{
+    CPURISCVState *env = &cpu->env;
+    int priv_version = -1;
+
+    if (cpu->cfg.priv_spec) {
+        if (!g_strcmp0(cpu->cfg.priv_spec, "v1.12.0")) {
+            priv_version = PRIV_VERSION_1_12_0;
+        } else if (!g_strcmp0(cpu->cfg.priv_spec, "v1.11.0")) {
+            priv_version = PRIV_VERSION_1_11_0;
+        } else if (!g_strcmp0(cpu->cfg.priv_spec, "v1.10.0")) {
+            priv_version = PRIV_VERSION_1_10_0;
+        } else {
+            error_setg(errp,
+                       "Unsupported privilege spec version '%s'",
+                       cpu->cfg.priv_spec);
+            return;
+        }
+
+        env->priv_ver = priv_version;
+    }
+}
+
+static void riscv_cpu_disable_priv_spec_isa_exts(RISCVCPU *cpu)
+{
+    CPURISCVState *env = &cpu->env;
+    int i;
+
+    /* Force disable extensions if priv spec version does not match */
+    for (i = 0; i < ARRAY_SIZE(isa_edata_arr); i++) {
+        if (isa_ext_is_enabled(cpu, &isa_edata_arr[i]) &&
+            (env->priv_ver < isa_edata_arr[i].min_version)) {
+            isa_ext_update_enabled(cpu, &isa_edata_arr[i], false);
+#ifndef CONFIG_USER_ONLY
+            warn_report("disabling %s extension for hart 0x" TARGET_FMT_lx
+                        " because privilege spec version does not match",
+                        isa_edata_arr[i].name, env->mhartid);
+#else
+            warn_report("disabling %s extension because "
+                        "privilege spec version does not match",
+                        isa_edata_arr[i].name);
+#endif
+        }
+    }
+}
+
 /*
  * Check consistency between chosen extensions while setting
  * cpu->cfg accordingly.
@@ -1082,6 +1128,12 @@ static void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, Error **errp)
         cpu->cfg.ext_zksed = true;
         cpu->cfg.ext_zksh = true;
     }
+
+    /*
+     * Disable isa extensions based on priv spec after we
+     * validated and set everything we need.
+     */
+    riscv_cpu_disable_priv_spec_isa_exts(cpu);
 }
 
 #ifndef CONFIG_USER_ONLY
@@ -1181,7 +1233,6 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
     CPURISCVState *env = &cpu->env;
     RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(dev);
     CPUClass *cc = CPU_CLASS(mcc);
-    int i, priv_version = -1;
     Error *local_err = NULL;
 
     cpu_exec_realizefn(cs, &local_err);
@@ -1190,23 +1241,10 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-    if (cpu->cfg.priv_spec) {
-        if (!g_strcmp0(cpu->cfg.priv_spec, "v1.12.0")) {
-            priv_version = PRIV_VERSION_1_12_0;
-        } else if (!g_strcmp0(cpu->cfg.priv_spec, "v1.11.0")) {
-            priv_version = PRIV_VERSION_1_11_0;
-        } else if (!g_strcmp0(cpu->cfg.priv_spec, "v1.10.0")) {
-            priv_version = PRIV_VERSION_1_10_0;
-        } else {
-            error_setg(errp,
-                       "Unsupported privilege spec version '%s'",
-                       cpu->cfg.priv_spec);
-            return;
-        }
-    }
-
-    if (priv_version >= PRIV_VERSION_1_10_0) {
-        env->priv_ver = priv_version;
+    riscv_cpu_validate_priv_spec(cpu, &local_err);
+    if (local_err != NULL) {
+        error_propagate(errp, local_err);
+        return;
     }
 
     riscv_cpu_validate_misa_priv(env, &local_err);
@@ -1215,23 +1253,6 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         return;
     }
 
-    /* Force disable extensions if priv spec version does not match */
-    for (i = 0; i < ARRAY_SIZE(isa_edata_arr); i++) {
-        if (isa_ext_is_enabled(cpu, &isa_edata_arr[i]) &&
-            (env->priv_ver < isa_edata_arr[i].min_version)) {
-            isa_ext_update_enabled(cpu, &isa_edata_arr[i], false);
-#ifndef CONFIG_USER_ONLY
-            warn_report("disabling %s extension for hart 0x" TARGET_FMT_lx
-                        " because privilege spec version does not match",
-                        isa_edata_arr[i].name, env->mhartid);
-#else
-            warn_report("disabling %s extension because "
-                        "privilege spec version does not match",
-                        isa_edata_arr[i].name);
-#endif
-        }
-    }
-
     if (cpu->cfg.epmp && !cpu->cfg.pmp) {
         /*
          * Enhanced PMP should only be available