[PATCHv4 5/5] kvm: only sync when attention bits set

[Michael S. Tsirkin]

Commit eb0dc6d0368072236dcd086d7fdc17fd3c4574d4 introduced apic
attention bitmask but kvm still syncs lapic unconditionally.
As that commit suggested and in anticipation of adding more attention
bits, only sync lapic if(apic_attention).

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
 arch/x86/kvm/x86.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4d77af0..4fa26f2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5375,7 +5375,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	if (unlikely(vcpu->arch.tsc_always_catchup))
 		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 
-	kvm_lapic_sync_from_vapic(vcpu);
+	if (unlikely(vcpu->arch.apic_attention))
+		kvm_lapic_sync_from_vapic(vcpu);
 
 	r = kvm_x86_ops->handle_exit(vcpu);
 out:
-- 
MST
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