From 2eec73437487aa690882cafddca6e4d93df46f26 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 1 Nov 2010 14:01:29 +0100 Subject: [PATCH] KVM: x86: Avoid issuing wbinvd twice Micro optimization to avoid calling wbinvd twice on the CPU that has to emulate it. As we might be preempted between smp_call_function_many and the local wbinvd, the cache might be filled again so that real work could be done uselessly. Signed-off-by: Jan Kiszka Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/x86.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 35f82f2c66f6..c10135bc0f2f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4007,13 +4007,15 @@ int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu) return X86EMUL_CONTINUE; if (kvm_x86_ops->has_wbinvd_exit()) { - preempt_disable(); + int cpu = get_cpu(); + + cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask); smp_call_function_many(vcpu->arch.wbinvd_dirty_mask, wbinvd_ipi, NULL, 1); - preempt_enable(); + put_cpu(); cpumask_clear(vcpu->arch.wbinvd_dirty_mask); - } - wbinvd(); + } else + wbinvd(); return X86EMUL_CONTINUE; } EXPORT_SYMBOL_GPL(kvm_emulate_wbinvd); -- 2.34.1