[Qemu-devel] [PATCH 2/6] target-i386: cpu: separate feature string parsing from CPU model lookup

[Eduardo Habkost]

Instead of using parsing the whole cpu_model string inside
cpu_x86_find_by_name(), first split it into the CPU model name and the
full feature string, then parse the feature string into pieces.

When using CPU model classes, those two pieces of information will be
used at different moments (CPU model name will be used to find CPU
class, feature string will be used after CPU object was created), so
making the split in two steps will make it easier to refactor the code
later.

This should also help on the CPU properties work, that will just need to
replace the cpu_x86_parse_featurestr() logic (and can keep the CPU model
lookup code as-is).

Signed-off-by: Eduardo Habkost <address@hidden>
---
Changes v1 -> v2:
 - Coding style changes
 - Replace "goto error" with "return -1"
---
 target-i386/cpu.c | 67 +++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 45 insertions(+), 22 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 7afe839..4090152 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1208,25 +1208,10 @@ static void x86_cpuid_set_tsc_freq(Object *obj, Visitor 
*v, void *opaque,
     cpu->env.tsc_khz = value / 1000;
 }
 
-static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
+static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *name)
 {
-    unsigned int i;
     x86_def_t *def;
 
-    char *s = g_strdup(cpu_model);
-    char *featurestr, *name = strtok(s, ",");
-    /* Features to be added*/
-    uint32_t plus_features = 0, plus_ext_features = 0;
-    uint32_t plus_ext2_features = 0, plus_ext3_features = 0;
-    uint32_t plus_kvm_features = kvm_default_features, plus_svm_features = 0;
-    uint32_t plus_7_0_ebx_features = 0;
-    /* Features to be removed */
-    uint32_t minus_features = 0, minus_ext_features = 0;
-    uint32_t minus_ext2_features = 0, minus_ext3_features = 0;
-    uint32_t minus_kvm_features = 0, minus_svm_features = 0;
-    uint32_t minus_7_0_ebx_features = 0;
-    uint32_t numvalue;
-
     for (def = x86_defs; def; def = def->next) {
         if (name && !strcmp(name, def->name)) {
             break;
@@ -1235,16 +1220,37 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, 
const char *cpu_model)
     if (kvm_enabled() && name && strcmp(name, "host") == 0) {
         kvm_cpu_fill_host(x86_cpu_def);
     } else if (!def) {
-        goto error;
+        return -1;
     } else {
         memcpy(x86_cpu_def, def, sizeof(*def));
     }
 
+    return 0;
+}
+
+/* Parse "+feature,-feature,feature=foo" CPU feature string
+ */
+static int cpu_x86_parse_featurestr(x86_def_t *x86_cpu_def, char *features)
+{
+    unsigned int i;
+    char *featurestr; /* Single 'key=value" string being parsed */
+    /* Features to be added*/
+    uint32_t plus_features = 0, plus_ext_features = 0;
+    uint32_t plus_ext2_features = 0, plus_ext3_features = 0;
+    uint32_t plus_kvm_features = kvm_default_features, plus_svm_features = 0;
+    uint32_t plus_7_0_ebx_features = 0;
+    /* Features to be removed */
+    uint32_t minus_features = 0, minus_ext_features = 0;
+    uint32_t minus_ext2_features = 0, minus_ext3_features = 0;
+    uint32_t minus_kvm_features = 0, minus_svm_features = 0;
+    uint32_t minus_7_0_ebx_features = 0;
+    uint32_t numvalue;
+
     add_flagname_to_bitmaps("hypervisor", &plus_features,
             &plus_ext_features, &plus_ext2_features, &plus_ext3_features,
             &plus_kvm_features, &plus_svm_features,  &plus_7_0_ebx_features);
 
-    featurestr = strtok(NULL, ",");
+    featurestr = features ? strtok(features, ",") : NULL;
 
     while (featurestr) {
         char *val;
@@ -1378,11 +1384,9 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, 
const char *cpu_model)
     if (x86_cpu_def->cpuid_7_0_ebx_features && x86_cpu_def->level < 7) {
         x86_cpu_def->level = 7;
     }
-    g_free(s);
     return 0;
 
 error:
-    g_free(s);
     return -1;
 }
 
@@ -1492,11 +1496,25 @@ int cpu_x86_register(X86CPU *cpu, const char *cpu_model)
     CPUX86State *env = &cpu->env;
     x86_def_t def1, *def = &def1;
     Error *error = NULL;
+    char *name, *features;
+    gchar **model_pieces;
 
     memset(def, 0, sizeof(*def));
 
-    if (cpu_x86_find_by_name(def, cpu_model) < 0)
-        return -1;
+    model_pieces = g_strsplit(cpu_model, ",", 2);
+    if (!model_pieces[0]) {
+        goto error;
+    }
+    name = model_pieces[0];
+    features = model_pieces[1];
+
+    if (cpu_x86_find_by_name(def, name) < 0) {
+        goto error;
+    }
+
+    if (cpu_x86_parse_featurestr(def, features) < 0) {
+        goto error;
+    }
     if (def->vendor1) {
         env->cpuid_vendor1 = def->vendor1;
         env->cpuid_vendor2 = def->vendor2;
@@ -1555,7 +1573,12 @@ int cpu_x86_register(X86CPU *cpu, const char *cpu_model)
         error_free(error);
         return -1;
     }
+
+    g_strfreev(model_pieces);
     return 0;
+error:
+    g_strfreev(model_pieces);
+    return -1;
 }
 
 #if !defined(CONFIG_USER_ONLY)
-- 
1.7.11.7