[Qemu-devel] (resend) Allow setting the vendor and model_id strings with x86's -cpu option

[Dan Kenigsberg]

Would you consider the following patch, that allows users to set two
important x86 cpu options from the command line? (the vendor and
model_id strings)

Every once in a while I am resending this little patch. It had generated
a lot of interest when it included silly bugs, but now it seems to be
largely ignored. However, it is important if one would like qemu to
impersonate a cpu closely as possible.

Regards,
    Dan.

commit 04433bad959a7a4c1b8a0c22bd50eab9bf181b32
Author: Dan Kenigsberg <[EMAIL PROTECTED]>
Date:   Thu Dec 20 15:43:15 2007 +0200

    Change vendor string and model id from the -cpu command line option

diff --git a/target-i386/helper2.c b/target-i386/helper2.c
index 551a0d8..b59bf92 100644
--- a/target-i386/helper2.c
+++ b/target-i386/helper2.c
@@ -121,6 +121,7 @@ typedef struct x86_def_t {
     const char *name;
     uint32_t level;
     uint32_t vendor1, vendor2, vendor3;
+    char model_id[48];
     int family;
     int model;
     int stepping;
@@ -262,7 +263,21 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, 
const char *cpu_model)
                     goto error;
                 }
                 x86_cpu_def->stepping = stepping;
-            } else {
+            } else if (!strcmp(featurestr, "vendor")) {
+                if (strlen(val) != 12) {
+                    fprintf(stderr, "vendor string must be 12 chars long\n");
+                    x86_cpu_def = 0;
+                    goto error;
+                }
+                x86_cpu_def->vendor1 = x86_cpu_def->vendor2 = 
x86_cpu_def->vendor3 = 0;
+                for(i = 0; i < 4; i++) {
+                    x86_cpu_def->vendor1 |= ((unsigned char)val[i    ]) << (8 
* i);
+                    x86_cpu_def->vendor2 |= ((unsigned char)val[i + 4]) << (8 
* i);
+                    x86_cpu_def->vendor3 |= ((unsigned char)val[i + 8]) << (8 
* i);
+                }
+            } else if (!strcmp(featurestr, "model_id"))
+                strncpy(x86_cpu_def->model_id, val, 48);
+            else {
                 fprintf(stderr, "unrecognized feature %s\n", featurestr);
                 x86_cpu_def = 0;
                 goto error;
@@ -323,13 +338,14 @@ static int cpu_x86_register (CPUX86State *env, const char 
*cpu_model)
     env->cpuid_ext3_features = def->ext3_features;
     {
         const char *model_id = "QEMU Virtual CPU version " QEMU_VERSION;
-        int c, len, i;
-        len = strlen(model_id);
+        int c = -1, i;
+       
+        if (def->model_id[0] != '\0')
+            model_id = def->model_id;
+
         for(i = 0; i < 48; i++) {
-            if (i >= len)
-                c = '\0';
-            else
-                c = model_id[i];
+            if (c != '\0')
+                c = (unsigned char)model_id[i];
             env->cpuid_model[i >> 2] |= c << (8 * (i & 3));
         }
     }