Re: [Qemu-devel] [PATCH v2] target-i386: Print warning when mixing [+-]foo and foo=(on|off)

[Igor Mammedov]

On Fri, 21 Oct 2016 17:41:13 -0200
Eduardo Habkost <address@hidden> wrote:

> Print a warning when mixing [+-]foo and foo=(on|off) in the -cpu
> argument in a way that will break in the future.
> 
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> Changes v1 -> v2:
> * Coding style fixes
> * Print "compatibility won't be kept" warning only once
> * Move subprocess test code inside
>   #ifdef CONFIG_HAS_GLIB_SUBPROCESS_TESTS
> ---
>  target-i386/cpu.c             | 24 ++++++++++++++++++++++++
>  tests/test-x86-cpuid-compat.c | 26 +++++++++++++++++++++-----
>  2 files changed, 45 insertions(+), 5 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index d95514c..dd5b7a7 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -1973,6 +1973,11 @@ static const char *x86_cpu_feature_name(FeatureWord w, 
> int bitnr)
>   */
>  static GList *plus_features, *minus_features;
>  
> +static gint compare_string(gconstpointer a, gconstpointer b)
> +{
> +    return g_strcmp0(a, b);
> +}
> +
>  /* Parse "+feature,-feature,feature=foo" CPU feature string
>   */
>  static void x86_cpu_parse_featurestr(const char *typename, char *features,
> @@ -1981,6 +1986,7 @@ static void x86_cpu_parse_featurestr(const char 
> *typename, char *features,
>      char *featurestr; /* Single 'key=value" string being parsed */
>      Error *local_err = NULL;
>      static bool cpu_globals_initialized;
> +    bool ambiguous = false;
>  
>      if (cpu_globals_initialized) {
>          return;
> @@ -2022,6 +2028,19 @@ static void x86_cpu_parse_featurestr(const char 
> *typename, char *features,
>          feat2prop(featurestr);
>          name = featurestr;
>  
> +        if (g_list_find_custom(plus_features, name, compare_string)) {
> +            error_report("warning: Ambiguous CPU model string. "
> +                         "Don't mix both \"+%s\" and \"%s=%s\"",
> +                         name, name, val);
> +            ambiguous = true;
> +        }
> +        if (g_list_find_custom(minus_features, name, compare_string)) {
> +            error_report("warning: Ambiguous CPU model string. "
> +                         "Don't mix both \"-%s\" and \"%s=%s\"",
> +                         name, name, val);
> +            ambiguous = true;
> +        }
> +
>          /* Special case: */
>          if (!strcmp(name, "tsc-freq")) {
>              int64_t tsc_freq;
> @@ -2046,6 +2065,11 @@ static void x86_cpu_parse_featurestr(const char 
> *typename, char *features,
>          qdev_prop_register_global(prop);
>      }
>  
> +    if (ambiguous) {
> +        error_report("warning: Compatibility of ambiguous CPU model "
> +                     "strings won't be kept on future QEMU versions");
> +    }
> +
>      if (local_err) {
>          error_propagate(errp, local_err);
>      }
> diff --git a/tests/test-x86-cpuid-compat.c b/tests/test-x86-cpuid-compat.c
> index 260dd27..df3fc7b 100644
> --- a/tests/test-x86-cpuid-compat.c
> +++ b/tests/test-x86-cpuid-compat.c
> @@ -76,7 +76,7 @@ static void add_cpuid_test(const char *name, const char 
> *cmdline,
>      qtest_add_data_func(name, args, test_cpuid_prop);
>  }
>  
> -static void test_plus_minus(void)
> +static void test_plus_minus_subprocess(void)
>  {
>      char *path;
>  
> @@ -86,9 +86,8 @@ static void test_plus_minus(void)
>       * 3) Old feature names with underscores (e.g. "sse4_2")
>       *    should keep working
>       *
> -     * Note: rules 1 and 2 are planned to be removed soon, but we
> -     * need to keep compatibility for a while until we start
> -     * warning users about it.
> +     * Note: rules 1 and 2 are planned to be removed soon, and
> +     * should generate a warning.
>       */
>      qtest_start("-cpu 
> pentium,-fpu,+fpu,-mce,mce=on,+cx8,cx8=off,+sse4_1,sse4_2=on");
>      path = get_cpu0_qom_path();
> @@ -108,11 +107,28 @@ static void test_plus_minus(void)
>      g_free(path);
>  }
>  
> +#ifdef CONFIG_HAS_GLIB_SUBPROCESS_TESTS
> +static void test_plus_minus(void)
> +{
> +    g_test_trap_subprocess("/x86/cpuid/parsing-plus-minus/subprocess", 0, 0);
> +    g_test_trap_assert_passed();
> +    g_test_trap_assert_stderr("*Ambiguous CPU model string. "
> +                              "Don't mix both \"-mce\" and \"mce=on\"*");
> +    g_test_trap_assert_stderr("*Ambiguous CPU model string. "
> +                              "Don't mix both \"+cx8\" and \"cx8=off\"*");
> +    g_test_trap_assert_stdout("");
> +}
> +#endif
Are there any reason to keep both subprocess and inprocess variants?

> +
>  int main(int argc, char **argv)
>  {
>      g_test_init(&argc, &argv, NULL);
>  
> -    qtest_add_func("x86/cpuid/parsing-plus-minus", test_plus_minus);
> +    g_test_add_func("/x86/cpuid/parsing-plus-minus/subprocess",
> +                    test_plus_minus_subprocess);
> +#ifdef CONFIG_HAS_GLIB_SUBPROCESS_TESTS
> +    g_test_add_func("/x86/cpuid/parsing-plus-minus", test_plus_minus);
> +#endif
>  
>      /* Original level values for CPU models: */
>      add_cpuid_test("x86/cpuid/phenom/level",