[Qemu-devel] [PATCH 10/37] target-i386: parse cpu_model string into set of stringified properties

[Igor Mammedov <imammedo@redhat.com>]

cpu_model string does represent features in following format:
 ([+-]feat)|(feat=foo)|(feat)
which makes it impossible directly use property infrastructure
to set features on CPU.
This patch introduces parser that splits CPU name from cpu_model and
converts legacy features string into canonized set of strings that
is compatible with property manipulation infrastructure.

 - convert CPUID features "feat" to "f-feat" format used by static properties

PS:
  * later it could be used as a hook to convert legacy command line
    features to global properties. Then marked as deprecated and
    removed with -cpu option in the future.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 v2:
  * compiler complains that it's unused function but I guess it is
    easier for review this way, for pull req I'll squash it into next
    patch
  * fix spelling error
  * initialize sptr, due to a CentOS6 compiler warning, that
    breaks build when -Werror is set. Suggested-by: Don Slutz
 v3:
  * Mingw doesn't have strtok_r(), use g_strsplit() instead of it.
        Suggested-by: Blue Swirl
 v4:
  * convert "+/-feat" to CPUID static features format "f-feat"
  * fixup xlevel in compat_normalize_cpu_model() instead of its property
    setter, it's needed for moving xlevel into static properties
---
 target-i386/cpu.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 target-i386/cpu.h |  2 ++
 2 files changed, 82 insertions(+)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index dbf2be7..4bbfe9b 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1250,6 +1250,86 @@ static void cpudef_2_x86_cpu(X86CPU *cpu, x86_def_t *def, Error **errp)
     }
 }
 
+/* convert legacy cpumodel string to string cpu_name and
+ * a uniform set of custom features that will be applied to CPU
+ * using object_property_parse()
+ */
+void compat_normalize_cpu_model(const char *cpu_model, char **cpu_name,
+                                        QDict **features, Error **errp)
+{
+    int i;
+    gchar **feat_array = g_strsplit(cpu_model, ",", 0);
+    *features = qdict_new();
+
+    g_assert(feat_array[0] != NULL);
+    *cpu_name = g_strdup(feat_array[0]);
+
+    for (i = 1; feat_array[i]; ++i) {
+        gchar *featurestr = feat_array[i];
+        char *val;
+        if (featurestr[0] == '+' || featurestr[0] == '-') {
+            const gchar *feat = featurestr + 1;
+            gchar *cpuid_fname = g_strconcat("f-", feat, NULL);
+
+            if (qdev_prop_find(DEVICE_CLASS(object_class_by_name(TYPE_X86_CPU)),
+                               cpuid_fname)) {
+                feat = cpuid_fname;
+            }
+
+            if (featurestr[0] == '+') {
+                /*
+                 * preseve legacy behaviour, if feature was disabled once
+                 * do not allow to enable it again
+                 */
+                if (!qdict_haskey(*features, feat)) {
+                    qdict_put(*features, feat, qstring_from_str("on"));
+                }
+            } else {
+                qdict_put(*features, feat, qstring_from_str("off"));
+            }
+
+            g_free(cpuid_fname);
+        } else {
+            val = strchr(featurestr, '=');
+            if (val) {
+                *val = 0; val++;
+                if (!strcmp(featurestr, "vendor")) {
+                    qdict_put(*features, "vendor-override",
+                              qstring_from_str("on"));
+                    qdict_put(*features, featurestr, qstring_from_str(val));
+                } else if (!strcmp(featurestr, "tsc_freq")) {
+                    qdict_put(*features, "tsc-frequency",
+                              qstring_from_str(val));
+                } else if (!strcmp(featurestr, "xlevel")) {
+                    uint32_t numvalue;
+                    char *err;
+                    numvalue = strtoul(val, &err, 0);
+                    if (!*val || *err) {
+                        error_setg(errp, "bad xlevel value %s", val);
+                        goto out;
+                    }
+                    if (numvalue < 0x80000000) {
+                        numvalue += 0x80000000;
+                        fprintf(stderr, "warning: xlevel: %s is too small,"
+                                "correcting it to: %u\n", val, numvalue);
+                    }
+                    val = g_strdup_printf("%u", numvalue);
+                    qdict_put(*features, featurestr, qstring_from_str(val));
+                    g_free(val);
+                } else {
+                    qdict_put(*features, featurestr, qstring_from_str(val));
+                }
+            } else {
+                qdict_put(*features, featurestr, qstring_from_str("on"));
+            }
+        }
+    }
+
+out:
+    g_strfreev(feat_array);
+    return;
+}
+
 static int cpu_x86_find_by_name(X86CPU *cpu, x86_def_t *x86_cpu_def,
                                 const char *cpu_model, Error **errp)
 {
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 871c270..7903413 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -958,6 +958,8 @@ int cpu_x86_register(X86CPU *cpu, const char *cpu_model);
 void cpu_clear_apic_feature(CPUX86State *env);
 void host_cpuid(uint32_t function, uint32_t count,
                 uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx);
+void compat_normalize_cpu_model(const char *cpu_model, char **cpu_name,
+                                        QDict **features, Error **errp);
 
 /* helper.c */
 int cpu_x86_handle_mmu_fault(CPUX86State *env, target_ulong addr,
-- 
1.7.11.7