iommu: KVM: Split "struct vcpu_data" into separate AMD vs. Intel structs

Split the vcpu_data structure that serves as a handoff from KVM to IOMMU
drivers into vendor specific structures.  Overloading a single structure
makes the code hard to read and maintain, is *very* misleading as it
suggests that mixing vendors is actually supported, and bastardizing
Intel's posted interrupt descriptor address when AMD's IOMMU already has
its own structure is quite unnecessary.

Tested-by: Sairaj Kodilkar <sarunkod@amd.com>
Link: https://lore.kernel.org/r/20250611224604.313496-33-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/include/asm/irq_remapping.h

@@ -26,7 +26,20 @@ enum {
 	IRQ_REMAP_X2APIC_MODE,
 };
 
-struct vcpu_data {
+/*
+ * This is mainly used to communicate information back-and-forth
+ * between SVM and IOMMU for setting up and tearing down posted
+ * interrupt
+ */
+struct amd_iommu_pi_data {
+	u64 vapic_addr;		/* Physical address of the vCPU's vAPIC. */
+	u32 ga_tag;
+	u32 vector;		/* Guest vector of the interrupt */
+	bool is_guest_mode;
+	void *ir_data;
+};
+
+struct intel_iommu_pi_data {
 	u64 pi_desc_addr;	/* Physical address of PI Descriptor */
 	u32 vector;		/* Guest vector of the interrupt */
 };

arch/x86/kvm/svm/avic.c

@@ -823,23 +823,18 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
 	 */
 	if (vcpu && kvm_vcpu_apicv_active(vcpu)) {
 		/*
-		 * Try to enable guest_mode in IRTE.  Note, the address
-		 * of the vCPU's AVIC backing page is passed to the
-		 * IOMMU via vcpu_info->pi_desc_addr.
+		 * Try to enable guest_mode in IRTE.
 		 */
-		struct vcpu_data vcpu_info = {
-			.pi_desc_addr = avic_get_backing_page_address(to_svm(vcpu)),
-			.vector = vector,
-		};
-
-		struct amd_iommu_pi_data pi = {
-			.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id, vcpu->vcpu_id),
+		struct amd_iommu_pi_data pi_data = {
+			.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id,
+					     vcpu->vcpu_id),
 			.is_guest_mode = true,
-			.vcpu_data = &vcpu_info,
+			.vapic_addr = avic_get_backing_page_address(to_svm(vcpu)),
+			.vector = vector,
 		};
 		int ret;
 
-		ret = irq_set_vcpu_affinity(host_irq, &pi);
+		ret = irq_set_vcpu_affinity(host_irq, &pi_data);
 		if (ret)
 			return ret;
 
@@ -850,7 +845,7 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
 		 * we can reference to them directly when we update vcpu
 		 * scheduling information in IOMMU irte.
 		 */
-		return svm_ir_list_add(to_svm(vcpu), irqfd, &pi);
+		return svm_ir_list_add(to_svm(vcpu), irqfd, &pi_data);
 	}
 	return irq_set_vcpu_affinity(host_irq, NULL);
 }

arch/x86/kvm/vmx/posted_intr.c

@@ -303,12 +303,12 @@ int vmx_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
 		       struct kvm_vcpu *vcpu, u32 vector)
 {
 	if (vcpu) {
-		struct vcpu_data vcpu_info = {
+		struct intel_iommu_pi_data pi_data = {
 			.pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu)),
 			.vector = vector,
 		};
 
-		return irq_set_vcpu_affinity(host_irq, &vcpu_info);
+		return irq_set_vcpu_affinity(host_irq, &pi_data);
 	} else {
 		return irq_set_vcpu_affinity(host_irq, NULL);
 	}

drivers/iommu/amd/iommu.c

@@ -3860,10 +3860,10 @@ int amd_iommu_deactivate_guest_mode(void *data)
 }
 EXPORT_SYMBOL(amd_iommu_deactivate_guest_mode);
 
-static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
+static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *info)
 {
 	int ret;
-	struct amd_iommu_pi_data *pi_data = vcpu_info;
+	struct amd_iommu_pi_data *pi_data = info;
 	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;
@@ -3886,14 +3886,10 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
 	ir_data->cfg = irqd_cfg(data);
 
 	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_root_ptr = (pi_data->vapic_addr >> 12);
+		ir_data->ga_vector = pi_data->vector;
 		ir_data->ga_tag = pi_data->ga_tag;
 		ret = amd_iommu_activate_guest_mode(ir_data);
 	} else {

drivers/iommu/intel/irq_remapping.c

@@ -1244,10 +1244,10 @@ static void intel_ir_compose_msi_msg(struct irq_data *irq_data,
 static int intel_ir_set_vcpu_affinity(struct irq_data *data, void *info)
 {
 	struct intel_ir_data *ir_data = data->chip_data;
-	struct vcpu_data *vcpu_pi_info = info;
+	struct intel_iommu_pi_data *pi_data = info;
 
 	/* stop posting interrupts, back to the default mode */
-	if (!vcpu_pi_info) {
+	if (!pi_data) {
 		__intel_ir_reconfigure_irte(data, true);
 	} else {
 		struct irte irte_pi;
@@ -1265,10 +1265,10 @@ static int intel_ir_set_vcpu_affinity(struct irq_data *data, void *info)
 		/* Update the posted mode fields */
 		irte_pi.p_pst = 1;
 		irte_pi.p_urgent = 0;
-		irte_pi.p_vector = vcpu_pi_info->vector;
-		irte_pi.pda_l = (vcpu_pi_info->pi_desc_addr >>
+		irte_pi.p_vector = pi_data->vector;
+		irte_pi.pda_l = (pi_data->pi_desc_addr >>
 				(32 - PDA_LOW_BIT)) & ~(-1UL << PDA_LOW_BIT);
-		irte_pi.pda_h = (vcpu_pi_info->pi_desc_addr >> 32) &
+		irte_pi.pda_h = (pi_data->pi_desc_addr >> 32) &
 				~(-1UL << PDA_HIGH_BIT);
 
 		ir_data->irq_2_iommu.posted_vcpu = true;

include/linux/amd-iommu.h

@@ -12,18 +12,6 @@
 
 struct amd_iommu;
 
-/*
- * This is mainly used to communicate information back-and-forth
- * between SVM and IOMMU for setting up and tearing down posted
- * interrupt
- */
-struct amd_iommu_pi_data {
-	u32 ga_tag;
-	bool is_guest_mode;
-	struct vcpu_data *vcpu_data;
-	void *ir_data;
-};
-
 #ifdef CONFIG_AMD_IOMMU
 
 struct task_struct;