kvm: x86: Introduce APICv x86 ops for checking APIC inhibit reasons

Inibit reason bits are used to determine if APICv deactivation is
applicable for a particular hardware virtualization architecture.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -1123,6 +1123,7 @@ struct kvm_x86_ops {
 	void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
 	void (*enable_irq_window)(struct kvm_vcpu *vcpu);
 	void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
+	bool (*check_apicv_inhibit_reasons)(ulong bit);
 	void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu);
 	void (*hwapic_irr_update)(struct kvm_vcpu *vcpu, int max_irr);
 	void (*hwapic_isr_update)(struct kvm_vcpu *vcpu, int isr);

arch/x86/kvm/svm.c

@@ -7298,6 +7298,13 @@ static bool svm_apic_init_signal_blocked(struct kvm_vcpu *vcpu)
 		   (svm->vmcb->control.intercept & (1ULL << INTERCEPT_INIT));
 }
 
+static bool svm_check_apicv_inhibit_reasons(ulong bit)
+{
+	ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE);
+
+	return supported & BIT(bit);
+}
+
 static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.cpu_has_kvm_support = has_svm,
 	.disabled_by_bios = is_disabled,
@@ -7373,6 +7380,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.update_cr8_intercept = update_cr8_intercept,
 	.set_virtual_apic_mode = svm_set_virtual_apic_mode,
 	.refresh_apicv_exec_ctrl = svm_refresh_apicv_exec_ctrl,
+	.check_apicv_inhibit_reasons = svm_check_apicv_inhibit_reasons,
 	.load_eoi_exitmap = svm_load_eoi_exitmap,
 	.hwapic_irr_update = svm_hwapic_irr_update,
 	.hwapic_isr_update = svm_hwapic_isr_update,

arch/x86/kvm/vmx/vmx.c

@@ -7710,6 +7710,13 @@ static __exit void hardware_unsetup(void)
 	free_kvm_area();
 }
 
+static bool vmx_check_apicv_inhibit_reasons(ulong bit)
+{
+	ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE);
+
+	return supported & BIT(bit);
+}
+
 static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.cpu_has_kvm_support = cpu_has_kvm_support,
 	.disabled_by_bios = vmx_disabled_by_bios,
@@ -7785,6 +7792,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.refresh_apicv_exec_ctrl = vmx_refresh_apicv_exec_ctrl,
 	.load_eoi_exitmap = vmx_load_eoi_exitmap,
 	.apicv_post_state_restore = vmx_apicv_post_state_restore,
+	.check_apicv_inhibit_reasons = vmx_check_apicv_inhibit_reasons,
 	.hwapic_irr_update = vmx_hwapic_irr_update,
 	.hwapic_isr_update = vmx_hwapic_isr_update,
 	.guest_apic_has_interrupt = vmx_guest_apic_has_interrupt,

arch/x86/kvm/x86.c

@@ -8034,6 +8034,10 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_update_apicv);
  */
 void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
 {
+	if (!kvm_x86_ops->check_apicv_inhibit_reasons ||
+	    !kvm_x86_ops->check_apicv_inhibit_reasons(bit))
+		return;
+
 	if (activate) {
 		if (!test_and_clear_bit(bit, &kvm->arch.apicv_inhibit_reasons) ||
 		    !kvm_apicv_activated(kvm))