[PATCH v8 05/19] target/riscv/tcg: update priv_ver on user_set extensions

[Daniel Henrique Barboza]

We'll add a new bare CPU type that won't have any default priv_ver. This
means that the CPU will default to priv_ver = 0, i.e. 1.10.0.

At the same we'll allow these CPUs to enable extensions at will, but
then, if the extension has a priv_ver newer than 1.10, we'll end up
disabling it. Users will then need to manually set priv_ver to something
other than 1.10 to enable the extensions they want, which is not ideal.

Change the setter() of multi letter extensions to allow user enabled
extensions to bump the priv_ver of the CPU. This will make it
conveniente for users to enable extensions for CPUs that doesn't set a
default priv_ver.

This change does not affect any existing CPU: vendor CPUs does not allow
extensions to be enabled, and generic CPUs are already set to priv_ver
LATEST.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
---
 target/riscv/tcg/tcg-cpu.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index f54069d06f..b88fce98a4 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -114,6 +114,22 @@ static int cpu_cfg_ext_get_min_version(uint32_t ext_offset)
     g_assert_not_reached();
 }
 
+static void cpu_validate_multi_ext_priv_ver(CPURISCVState *env,
+                                            uint32_t ext_offset)
+{
+    int ext_priv_ver;
+
+    if (env->priv_ver == PRIV_VERSION_LATEST) {
+        return;
+    }
+
+    ext_priv_ver = cpu_cfg_ext_get_min_version(ext_offset);
+
+    if (env->priv_ver < ext_priv_ver) {
+        env->priv_ver = ext_priv_ver;
+    }
+}
+
 static void cpu_cfg_ext_auto_update(RISCVCPU *cpu, uint32_t ext_offset,
                                     bool value)
 {
@@ -829,6 +845,10 @@ static void cpu_set_multi_ext_cfg(Object *obj, Visitor *v, 
const char *name,
         return;
     }
 
+    if (value) {
+        cpu_validate_multi_ext_priv_ver(&cpu->env, multi_ext_cfg->offset);
+    }
+
     isa_ext_update_enabled(cpu, multi_ext_cfg->offset, value);
 }
 
-- 
2.41.0