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authorRadim Krčmář <rkrcmar@redhat.com>2016-10-10 17:28:48 +0200
committerEduardo Habkost <ehabkost@redhat.com>2016-10-17 15:44:49 -0200
commit2a138ec3af871cd42a982eb401f16dcb74cba8d3 (patch)
treec861b9f9dc822383ba6571df94f2a4d097eed6a6
parentfb506e701e9bafa3e0685747c1c98962c52d1962 (diff)
downloadfocaccia-qemu-2a138ec3af871cd42a982eb401f16dcb74cba8d3.tar.gz
focaccia-qemu-2a138ec3af871cd42a982eb401f16dcb74cba8d3.zip
target-i386/kvm: cache the return value of kvm_enable_x2apic()
Assume that KVM would have returned the same on subsequent runs.
Abstract the memoizaiton pattern into macros and call it memorize as
adding the r makes it less obscure.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
-rw-r--r--target-i386/kvm.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 0fd6646486..0472f45fd0 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -129,10 +129,23 @@ static bool kvm_x2apic_api_set_flags(uint64_t flags)
     return !kvm_vm_enable_cap(s, KVM_CAP_X2APIC_API, 0, flags);
 }
 
+#define MEMORIZE(fn) \
+    ({ \
+        static typeof(fn) _result; \
+        static bool _memorized; \
+        \
+        if (_memorized) { \
+            return _result; \
+        } \
+        _memorized = true; \
+        _result = fn; \
+    })
+
 bool kvm_enable_x2apic(void)
 {
-    return kvm_x2apic_api_set_flags(KVM_X2APIC_API_USE_32BIT_IDS |
-                                    KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK);
+    return MEMORIZE(
+             kvm_x2apic_api_set_flags(KVM_X2APIC_API_USE_32BIT_IDS |
+                                      KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK));
 }
 
 static int kvm_get_tsc(CPUState *cs)