KVM: X86: implement the logic for spinlock optimization
get_cpl requires vcpu_load, so we must cache the result (whether the vcpu was preempted when its cpl=0) in kvm_vcpu_arch. Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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@ -688,6 +688,9 @@ struct kvm_vcpu_arch {
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/* GPA available (AMD only) */
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bool gpa_available;
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/* be preempted when it's in kernel-mode(cpl=0) */
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bool preempted_in_kernel;
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};
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struct kvm_lpage_info {
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@ -1274,7 +1274,7 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
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switch (code) {
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case HVCALL_NOTIFY_LONG_SPIN_WAIT:
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kvm_vcpu_on_spin(vcpu, false);
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kvm_vcpu_on_spin(vcpu, true);
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break;
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case HVCALL_POST_MESSAGE:
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case HVCALL_SIGNAL_EVENT:
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@ -3749,7 +3749,10 @@ static int interrupt_window_interception(struct vcpu_svm *svm)
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static int pause_interception(struct vcpu_svm *svm)
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{
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kvm_vcpu_on_spin(&svm->vcpu, false);
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struct kvm_vcpu *vcpu = &svm->vcpu;
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bool in_kernel = (svm_get_cpl(vcpu) == 0);
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kvm_vcpu_on_spin(vcpu, in_kernel);
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return 1;
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}
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@ -6781,7 +6781,13 @@ static int handle_pause(struct kvm_vcpu *vcpu)
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if (ple_gap)
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grow_ple_window(vcpu);
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kvm_vcpu_on_spin(vcpu, false);
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/*
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* Intel sdm vol3 ch-25.1.3 says: The "PAUSE-loop exiting"
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* VM-execution control is ignored if CPL > 0. OTOH, KVM
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* never set PAUSE_EXITING and just set PLE if supported,
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* so the vcpu must be CPL=0 if it gets a PAUSE exit.
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*/
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kvm_vcpu_on_spin(vcpu, true);
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return kvm_skip_emulated_instruction(vcpu);
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}
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@ -2873,6 +2873,10 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
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void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
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{
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int idx;
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if (vcpu->preempted)
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vcpu->arch.preempted_in_kernel = !kvm_x86_ops->get_cpl(vcpu);
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/*
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* Disable page faults because we're in atomic context here.
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* kvm_write_guest_offset_cached() would call might_fault()
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@ -7985,6 +7989,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
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kvm_pmu_init(vcpu);
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vcpu->arch.pending_external_vector = -1;
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vcpu->arch.preempted_in_kernel = false;
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kvm_hv_vcpu_init(vcpu);
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@ -8434,7 +8439,7 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
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bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
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{
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return false;
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return vcpu->arch.preempted_in_kernel;
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}
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int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
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