[Qemu-devel] [PATCH 4/7] target-i386: kvm_cpu_fill_host(): No need to check xlevel2

[Eduardo Habkost]

There's no need to check CPU xlevel2 before calling
kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX), because:

 * The kernel won't return any entry for 0xC0000000 if host CPU vendor
   is not Centaur (See kvm_dev_ioctl_get_supported_cpuid() on the kernel
   code)
 * Similarly, the kernel won't return any entry for 0xC0000001 if
   CPUID[0xC0000000].EAX is < 0xC0000001
 * kvm_arch_get_supported_cpuid() will return 0 if no entry is returned
   by the kernel for the requested leaf

For similar reasons, we can simply set x86_cpu_def->xlevel2 directly
instead of making it conditional, because it will be set to 0 CPU vendor
is not Centaur.

This will simplify the kvm_cpu_fill_host() code a little.

Signed-off-by: Eduardo Habkost <address@hidden>
---
 target-i386/cpu.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 1a86bcf..8bc72c2 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1173,13 +1173,11 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
     cpu_x86_fill_model_id(x86_cpu_def->model_id);
 
     /* Call Centaur's CPUID instruction. */
-    eax = kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
-    if (eax >= 0xC0000001) {
-        /* Support VIA max extended level */
-        x86_cpu_def->xlevel2 = eax;
-        x86_cpu_def->features[FEAT_C000_0001_EDX] =
-                kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX);
-    }
+    x86_cpu_def->xlevel2 =
+        kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
+    /* Support VIA max extended level */
+    x86_cpu_def->features[FEAT_C000_0001_EDX] =
+        kvm_arch_get_supported_cpuid(s, 0xC0000001, 0, R_EDX);
 
     /* Other KVM-specific feature fields: */
     x86_cpu_def->features[FEAT_SVM] =
-- 
1.8.4.2