From 2a138ec3af871cd42a982eb401f16dcb74cba8d3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Date: Mon, 10 Oct 2016 17:28:48 +0200 Subject: [PATCH] target-i386/kvm: cache the return value of kvm_enable_x2apic() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Radim Krčmář Signed-off-by: Eduardo Habkost --- target-i386/kvm.c | 17 +++++++++++++++-- 1 file 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)