[PATCH v4 9/9] target/riscv/tcg: warn if profile exts are disabled

[Daniel Henrique Barboza]

Enabling a profile and then disabling some of its mandatory extensions
is a valid use. It can be useful for debugging and testing. But the
common expected use of enabling a profile is to enable all its mandatory
extensions.

Add an user warning when mandatory extensions from an enabled profile
are disabled in the command line, like we're already doing with RVG.

After this patch, this will throw warnings:

-cpu rv64,rva22u64=true,zihintpause=false,zicbom=false,zicboz=false

qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension 
zihintpause
qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension 
zicbom
qemu-system-riscv64: warning: Profile rva22u64 mandates disabled extension 
zicboz

Note that the following  will NOT throw warnings because the profile is
being enabled last, hence all its mandatory extensions will be enabled:

-cpu rv64,zihintpause=false,zicbom=false,zicboz=false,rva22u64=true

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
---
 target/riscv/tcg/tcg-cpu.c | 57 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index 4e90c726e9..ff2ebef63b 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -147,6 +147,22 @@ static int cpu_cfg_ext_get_min_version(uint32_t ext_offset)
     g_assert_not_reached();
 }
 
+static const char *cpu_cfg_ext_get_name(uint32_t ext_offset)
+{
+    const RISCVIsaExtData *edata;
+
+    for (edata = isa_edata_arr; edata && edata->name; edata++) {
+        if (edata->ext_enable_offset != ext_offset) {
+            continue;
+        }
+
+        return edata->name;
+    }
+
+    g_assert_not_reached();
+}
+
+
 static void cpu_cfg_ext_auto_update(RISCVCPU *cpu, uint32_t ext_offset,
                                     bool value)
 {
@@ -619,11 +635,52 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, 
Error **errp)
     riscv_cpu_disable_priv_spec_isa_exts(cpu);
 }
 
+static void riscv_cpu_validate_profile(RISCVCPU *cpu,
+                                       RISCVCPUProfile *profile)
+{
+    const char *warn_msg = "Profile %s mandates disabled extension %s";
+    int i;
+
+    for (i = 0; misa_bits[i] != 0; i++) {
+        uint32_t bit = misa_bits[i];
+
+        if (!(profile->misa_ext & bit)) {
+            continue;
+        }
+
+        if (!riscv_has_ext(&cpu->env, bit)) {
+            warn_report(warn_msg, profile->name, riscv_get_misa_ext_name(bit));
+        }
+    }
+
+    for (i = 0; profile->ext_offsets[i] != RISCV_PROFILE_EXT_LIST_END; i++) {
+        int ext_offset = profile->ext_offsets[i];
+
+        if (!isa_ext_is_enabled(cpu, ext_offset)) {
+            warn_report(warn_msg, profile->name,
+                        cpu_cfg_ext_get_name(ext_offset));
+        }
+    }
+}
+
+static void riscv_cpu_validate_profiles(RISCVCPU *cpu)
+{
+    for (int i = 0; riscv_profiles[i] != NULL; i++) {
+        RISCVCPUProfile *profile = riscv_profiles[i];
+
+        if (profile->user_set && profile->enabled) {
+            riscv_cpu_validate_profile(cpu, profile);
+        }
+    }
+}
+
 void riscv_tcg_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
 {
     CPURISCVState *env = &cpu->env;
     Error *local_err = NULL;
 
+    riscv_cpu_validate_profiles(cpu);
+
     riscv_cpu_validate_priv_spec(cpu, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
-- 
2.41.0