[Qemu-devel] [PATCH 1/2] allow hypervisor CPUID bit to be overriden

[Andre Przywara]

KVM defaults to the hypervisor CPUID bit to be set, whereas pure QEMU clears
it. On some occasions one want to set or clear it the other way round (for
instance to get HyperV running inside a guest).
Allow the default to be overridden on the command line and fix some
whitespace damage on the way.

Signed-off-by: Andre Przywara <address@hidden>
---
 target-i386/helper.c |   25 +++++++++++++------------
 1 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/target-i386/helper.c b/target-i386/helper.c
index 8a76abd..529f962 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -44,7 +44,7 @@ static const char *ext_feature_name[] = {
     "pni" /* Intel,AMD sse3 */, NULL, NULL, "monitor", "ds_cpl", "vmx", NULL 
/* Linux smx */, "est",
     "tm2", "ssse3", "cid", NULL, NULL, "cx16", "xtpr", NULL,
     NULL, NULL, "dca", NULL, NULL, NULL, NULL, "popcnt",
-       NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL, NULL, NULL, NULL, "hypervisor",
 };
 static const char *ext2_feature_name[] = {
     "fpu", "vme", "de", "pse", "tsc", "msr", "pae", "mce",
@@ -59,30 +59,30 @@ static const char *ext3_feature_name[] = {
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 };
 
-static void add_flagname_to_bitmaps(char *flagname, uint32_t *features, 
-                                    uint32_t *ext_features, 
-                                    uint32_t *ext2_features, 
+static void add_flagname_to_bitmaps(const char *flagname, uint32_t *features,
+                                    uint32_t *ext_features,
+                                    uint32_t *ext2_features,
                                     uint32_t *ext3_features)
 {
     int i;
     int found = 0;
 
-    for ( i = 0 ; i < 32 ; i++ ) 
+    for ( i = 0 ; i < 32 ; i++ )
         if (feature_name[i] && !strcmp (flagname, feature_name[i])) {
             *features |= 1 << i;
             found = 1;
         }
-    for ( i = 0 ; i < 32 ; i++ ) 
+    for ( i = 0 ; i < 32 ; i++ )
         if (ext_feature_name[i] && !strcmp (flagname, ext_feature_name[i])) {
             *ext_features |= 1 << i;
             found = 1;
         }
-    for ( i = 0 ; i < 32 ; i++ ) 
+    for ( i = 0 ; i < 32 ; i++ )
         if (ext2_feature_name[i] && !strcmp (flagname, ext2_feature_name[i])) {
             *ext2_features |= 1 << i;
             found = 1;
         }
-    for ( i = 0 ; i < 32 ; i++ ) 
+    for ( i = 0 ; i < 32 ; i++ )
         if (ext3_feature_name[i] && !strcmp (flagname, ext3_feature_name[i])) {
             *ext3_features |= 1 << i;
             found = 1;
@@ -330,6 +330,11 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, 
const char *cpu_model)
         goto error;
     memcpy(x86_cpu_def, def, sizeof(*def));
 
+    if (kvm_enabled()) {
+        add_flagname_to_bitmaps("hypervisor", &plus_features,
+            &plus_ext_features, &plus_ext2_features, &plus_ext3_features);
+    }
+
     featurestr = strtok(NULL, ",");
 
     while (featurestr) {
@@ -1523,10 +1528,6 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
uint32_t count,
         *ebx = (env->cpuid_apic_id << 24) | 8 << 8; /* CLFLUSH size in quad 
words, Linux wants it. */
         *ecx = env->cpuid_ext_features;
         *edx = env->cpuid_features;
-
-        /* "Hypervisor present" bit required for Microsoft SVVP */
-        if (kvm_enabled())
-            *ecx |= (1 << 31);
         break;
     case 2:
         /* cache info: needed for Pentium Pro compatibility */
-- 
1.6.1.3