kvm: x86: svm: Add support to (de)activate posted interrupts

Introduce interface for (de)activate posted interrupts, and
implement SVM hooks to toggle AMD IOMMU guest virtual APIC mode.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm.c

@@ -5155,17 +5155,52 @@ static void svm_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
 {
 }
 
+static int svm_set_pi_irte_mode(struct kvm_vcpu *vcpu, bool activate)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct amd_svm_iommu_ir *ir;
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (!kvm_arch_has_assigned_device(vcpu->kvm))
+		return 0;
+
+	/*
+	 * Here, we go through the per-vcpu ir_list to update all existing
+	 * interrupt remapping table entry targeting this vcpu.
+	 */
+	spin_lock_irqsave(&svm->ir_list_lock, flags);
+
+	if (list_empty(&svm->ir_list))
+		goto out;
+
+	list_for_each_entry(ir, &svm->ir_list, node) {
+		if (activate)
+			ret = amd_iommu_activate_guest_mode(ir->data);
+		else
+			ret = amd_iommu_deactivate_guest_mode(ir->data);
+		if (ret)
+			break;
+	}
+out:
+	spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+	return ret;
+}
+
 /* Note: Currently only used by Hyper-V. */
 static void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	struct vmcb *vmcb = svm->vmcb;
+	bool activated = kvm_vcpu_apicv_active(vcpu);
 
-	if (kvm_vcpu_apicv_active(vcpu))
+	if (activated)
 		vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
 	else
 		vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK;
 	mark_dirty(vmcb, VMCB_AVIC);
+
+	svm_set_pi_irte_mode(vcpu, activated);
 }
 
 static void svm_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)