kvm: Add CPUID support for VIA CPU

When KVM is running on VIA CPU with host cpu's model, the
feautures of VIA CPU will be passed into kvm guest by calling
the CPUID instruction for Centaur.

Signed-off-by: BrillyWu<brillywu@viatech.com.cn>
Signed-off-by: KaryJin<karyjin@viatech.com.cn>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 51 insertions, 2 deletions

diff --git a/target-i386/cpuid.c b/target-i386/cpuid.c
index e479a4dbd7..40a73c7d11 100644
--- a/target-i386/cpuid.c
+++ b/target-i386/cpuid.c
@@ -230,6 +230,9 @@ typedef struct x86_def_t {
     char model_id[48];
     int vendor_override;
     uint32_t flags;
+    /* Store the results of Centaur's CPUID instructions */
+    uint32_t ext4_features;
+    uint32_t xlevel2;
 } x86_def_t;
 
 #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE)
@@ -522,6 +525,18 @@ static int cpu_x86_fill_host(x86_def_t *x86_cpu_def)
     cpu_x86_fill_model_id(x86_cpu_def->model_id);
     x86_cpu_def->vendor_override = 0;
 
+    /* Call Centaur's CPUID instruction. */
+    if (x86_cpu_def->vendor1 == CPUID_VENDOR_VIA_1 &&
+        x86_cpu_def->vendor2 == CPUID_VENDOR_VIA_2 &&
+        x86_cpu_def->vendor3 == CPUID_VENDOR_VIA_3) {
+        host_cpuid(0xC0000000, 0, &eax, &ebx, &ecx, &edx);
+        if (eax >= 0xC0000001) {
+            /* Support VIA max extended level */
+            x86_cpu_def->xlevel2 = eax;
+            host_cpuid(0xC0000001, 0, &eax, &ebx, &ecx, &edx);
+            x86_cpu_def->ext4_features = edx;
+        }
+    }
 
     /*
      * Every SVM feature requires emulation support in KVM - so we can't just
@@ -855,6 +870,8 @@ int cpu_x86_register (CPUX86State *env, const char *cpu_model)
     env->cpuid_xlevel = def->xlevel;
     env->cpuid_kvm_features = def->kvm_features;
     env->cpuid_svm_features = def->svm_features;
+    env->cpuid_ext4_features = def->ext4_features;
+    env->cpuid_xlevel2 = def->xlevel2;
     if (!kvm_enabled()) {
         env->cpuid_features &= TCG_FEATURES;
         env->cpuid_ext_features &= TCG_EXT_FEATURES;
@@ -1035,8 +1052,18 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
 {
     /* test if maximum index reached */
     if (index & 0x80000000) {
-        if (index > env->cpuid_xlevel)
-            index = env->cpuid_level;
+        if (index > env->cpuid_xlevel) {
+            if (env->cpuid_xlevel2 > 0) {
+                /* Handle the Centaur's CPUID instruction. */
+                if (index > env->cpuid_xlevel2) {
+                    index = env->cpuid_xlevel2;
+                } else if (index < 0xC0000000) {
+                    index = env->cpuid_xlevel;
+                }
+            } else {
+                index =  env->cpuid_xlevel;
+            }
+        }
     } else {
         if (index > env->cpuid_level)
             index = env->cpuid_level;
@@ -1231,6 +1258,28 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
 		*edx = 0;
 	}
         break;
+    case 0xC0000000:
+        *eax = env->cpuid_xlevel2;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = 0;
+        break;
+    case 0xC0000001:
+        /* Support for VIA CPU's CPUID instruction */
+        *eax = env->cpuid_version;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = env->cpuid_ext4_features;
+        break;
+    case 0xC0000002:
+    case 0xC0000003:
+    case 0xC0000004:
+        /* Reserved for the future, and now filled with zero */
+        *eax = 0;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = 0;
+        break;
     default:
         /* reserved values: zero */
         *eax = 0;