diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index b7353e11da2e61ed39b42f53b2e25f6bb6bbc022..522f859408cbdbe3cd789b3a8ffe127d63032b0a 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -978,6 +978,8 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu) int h_physical_id = kvm_cpu_get_apicid(cpu); struct vcpu_svm *svm = to_svm(vcpu); + lockdep_assert_preemption_disabled(); + /* * Since the host physical APIC id is 8 bits, * we can support host APIC ID upto 255. @@ -1011,6 +1013,8 @@ void avic_vcpu_put(struct kvm_vcpu *vcpu) u64 entry; struct vcpu_svm *svm = to_svm(vcpu); + lockdep_assert_preemption_disabled(); + entry = READ_ONCE(*(svm->avic_physical_id_cache)); /* Nothing to do if IsRunning == '0' due to vCPU blocking. */ @@ -1023,30 +1027,42 @@ void avic_vcpu_put(struct kvm_vcpu *vcpu) WRITE_ONCE(*(svm->avic_physical_id_cache), entry); } -/* - * This function is called during VCPU halt/unhalt. - */ -static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run) -{ - int cpu = get_cpu(); - - WARN_ON(cpu != vcpu->cpu); - - if (kvm_vcpu_apicv_active(vcpu)) { - if (is_run) - avic_vcpu_load(vcpu, cpu); - else - avic_vcpu_put(vcpu); - } - put_cpu(); -} - void svm_vcpu_blocking(struct kvm_vcpu *vcpu) { - avic_set_running(vcpu, false); + if (!kvm_vcpu_apicv_active(vcpu)) + return; + + preempt_disable(); + + /* + * Unload the AVIC when the vCPU is about to block, _before_ + * the vCPU actually blocks. + * + * Any IRQs that arrive before IsRunning=0 will not cause an + * incomplete IPI vmexit on the source, therefore vIRR will also + * be checked by kvm_vcpu_check_block() before blocking. The + * memory barrier implicit in set_current_state orders writing + * IsRunning=0 before reading the vIRR. The processor needs a + * matching memory barrier on interrupt delivery between writing + * IRR and reading IsRunning; the lack of this barrier might be + * the cause of errata #1235). + */ + avic_vcpu_put(vcpu); + + preempt_enable(); } void svm_vcpu_unblocking(struct kvm_vcpu *vcpu) { - avic_set_running(vcpu, true); + int cpu; + + if (!kvm_vcpu_apicv_active(vcpu)) + return; + + cpu = get_cpu(); + WARN_ON(cpu != vcpu->cpu); + + avic_vcpu_load(vcpu, cpu); + + put_cpu(); }