iommu/amd: KVM: SVM: Pass NULL @vcpu_info to indicate "not guest mode"

Pass NULL to amd_ir_set_vcpu_affinity() to communicate "don't post to a
vCPU" now that there's no need to communicate information back to KVM
about the previous vCPU (KVM does its own tracking).

Tested-by: Sairaj Kodilkar <sarunkod@amd.com>
Link: https://lore.kernel.org/r/20250611224604.313496-24-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/svm/avic.c

@@ -928,18 +928,10 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
 		}
 	}
 
-	ret = 0;
-	if (enable_remapped_mode) {
-		/* Use legacy mode in IRTE */
-		struct amd_iommu_pi_data pi;
-
-		/**
-		 * Here, pi is used to:
-		 * - Tell IOMMU to use legacy mode for this interrupt.
-		 */
-		pi.is_guest_mode = false;
-		ret = irq_set_vcpu_affinity(host_irq, &pi);
-	}
+	if (enable_remapped_mode)
+		ret = irq_set_vcpu_affinity(host_irq, NULL);
+	else
+		ret = 0;
 out:
 	srcu_read_unlock(&kvm->irq_srcu, idx);
 	return ret;

drivers/iommu/amd/iommu.c

@@ -3864,7 +3864,6 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
 {
 	int ret;
 	struct amd_iommu_pi_data *pi_data = vcpu_info;
-	struct vcpu_data *vcpu_pi_info = pi_data->vcpu_data;
 	struct amd_ir_data *ir_data = data->chip_data;
 	struct irq_2_irte *irte_info = &ir_data->irq_2_irte;
 	struct iommu_dev_data *dev_data;
@@ -3885,9 +3884,14 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
 		return -EINVAL;
 
 	ir_data->cfg = irqd_cfg(data);
-	pi_data->ir_data = ir_data;
 
-	if (pi_data->is_guest_mode) {
+	if (pi_data) {
+		struct vcpu_data *vcpu_pi_info = pi_data->vcpu_data;
+
+		pi_data->ir_data = ir_data;
+
+		WARN_ON_ONCE(!pi_data->is_guest_mode);
+
 		ir_data->ga_root_ptr = (vcpu_pi_info->pi_desc_addr >> 12);
 		ir_data->ga_vector = vcpu_pi_info->vector;
 		ir_data->ga_tag = pi_data->ga_tag;