Revert "ANDROID: KVM: arm64: iommu: Create parent/child relation"

This reverts commit d5bc119656.

Bug: 233587962
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I7aded5e8adabfe9e717bb104edcdf072b581842e

arch/arm64/include/asm/kvm_host.h

@@ -385,7 +385,7 @@ enum pkvm_iommu_pm_event {
 
 int pkvm_iommu_driver_init(enum pkvm_iommu_driver_id drv_id, void *data, size_t size);
 int pkvm_iommu_register(struct device *dev, enum pkvm_iommu_driver_id drv_id,
-			phys_addr_t pa, size_t size, struct device *parent);
+			phys_addr_t pa, size_t size);
 int pkvm_iommu_suspend(struct device *dev);
 int pkvm_iommu_resume(struct device *dev);
 

arch/arm64/kvm/hyp/include/nvhe/iommu.h

@@ -26,12 +26,6 @@ struct pkvm_iommu_ops {
 	 */
 	int (*validate)(struct pkvm_iommu *dev);
 
-	/*
-	 * Validation of a new child device that is being register by
-	 * the parent device the child selected. Called with the host lock held.
-	 */
-	int (*validate_child)(struct pkvm_iommu *dev, struct pkvm_iommu *child);
-
 	/*
 	 * Callback to apply a host stage-2 mapping change at driver level.
 	 * Called before 'host_stage2_idmap_apply' with host lock held.
@@ -63,10 +57,7 @@ struct pkvm_iommu_ops {
 };
 
 struct pkvm_iommu {
-	struct pkvm_iommu *parent;
 	struct list_head list;
-	struct list_head siblings;
-	struct list_head children;
 	unsigned long id;
 	const struct pkvm_iommu_ops *ops;
 	phys_addr_t pa;
@@ -80,7 +71,6 @@ int __pkvm_iommu_driver_init(enum pkvm_iommu_driver_id id, void *data, size_t si
 int __pkvm_iommu_register(unsigned long dev_id,
 			  enum pkvm_iommu_driver_id drv_id,
 			  phys_addr_t dev_pa, size_t dev_size,
-			  unsigned long parent_id,
 			  void *kern_mem_va, size_t mem_size);
 int __pkvm_iommu_pm_notify(unsigned long dev_id,
 			   enum pkvm_iommu_pm_event event);

arch/arm64/kvm/hyp/nvhe/hyp-main.c

@@ -991,13 +991,11 @@ static void handle___pkvm_iommu_register(struct kvm_cpu_context *host_ctxt)
 	DECLARE_REG(enum pkvm_iommu_driver_id, drv_id, host_ctxt, 2);
 	DECLARE_REG(phys_addr_t, dev_pa, host_ctxt, 3);
 	DECLARE_REG(size_t, dev_size, host_ctxt, 4);
-	DECLARE_REG(unsigned long, parent_id, host_ctxt, 5);
-	DECLARE_REG(void *, mem, host_ctxt, 6);
-	DECLARE_REG(size_t, mem_size, host_ctxt, 7);
+	DECLARE_REG(void *, mem, host_ctxt, 5);
+	DECLARE_REG(size_t, mem_size, host_ctxt, 6);
 
 	cpu_reg(host_ctxt, 1) = __pkvm_iommu_register(dev_id, drv_id, dev_pa,
-						      dev_size, parent_id,
-						      mem, mem_size);
+						      dev_size, mem, mem_size);
 }
 
 static void handle___pkvm_iommu_pm_notify(struct kvm_cpu_context *host_ctxt)

arch/arm64/kvm/hyp/nvhe/iommu.c

@@ -289,7 +289,6 @@ out:
 int __pkvm_iommu_register(unsigned long dev_id,
 			  enum pkvm_iommu_driver_id drv_id,
 			  phys_addr_t dev_pa, size_t dev_size,
-			  unsigned long parent_id,
 			  void *kern_mem_va, size_t mem_size)
 {
 	struct pkvm_iommu *dev = NULL;
@@ -334,7 +333,6 @@ int __pkvm_iommu_register(unsigned long dev_id,
 
 	/* Populate the new device entry. */
 	*dev = (struct pkvm_iommu){
-		.children = LIST_HEAD_INIT(dev->children),
 		.id = dev_id,
 		.ops = drv->ops,
 		.pa = dev_pa,
@@ -346,20 +344,6 @@ int __pkvm_iommu_register(unsigned long dev_id,
 		goto out;
 	}
 
-	if (parent_id) {
-		dev->parent = find_iommu_by_id(parent_id);
-		if (!dev->parent) {
-			ret = -EINVAL;
-			goto out;
-		}
-
-		if (dev->parent->ops->validate_child) {
-			ret = dev->parent->ops->validate_child(dev->parent, dev);
-			if (ret)
-				goto out;
-		}
-	}
-
 	if (dev->ops->validate) {
 		ret = dev->ops->validate(dev);
 		if (ret)
@@ -385,8 +369,6 @@ int __pkvm_iommu_register(unsigned long dev_id,
 
 	/* Register device and prevent host from mapping the MMIO range. */
 	list_add_tail(&dev->list, &iommu_list);
-	if (dev->parent)
-		list_add_tail(&dev->siblings, &dev->parent->children);
 
 out:
 	if (ret)

arch/arm64/kvm/iommu.c

@@ -18,7 +18,7 @@ int pkvm_iommu_driver_init(enum pkvm_iommu_driver_id id, void *data, size_t size
 }
 
 int pkvm_iommu_register(struct device *dev, enum pkvm_iommu_driver_id drv_id,
-			phys_addr_t pa, size_t size, struct device *parent)
+			phys_addr_t pa, size_t size)
 {
 	void *mem;
 	int ret;
@@ -29,15 +29,14 @@ int pkvm_iommu_register(struct device *dev, enum pkvm_iommu_driver_id drv_id,
 	 * We assume that hyp never allocates more than a page per hypcall.
 	 */
 	ret = kvm_call_hyp_nvhe(__pkvm_iommu_register, dev_to_id(dev),
-				drv_id, pa, size, dev_to_id(parent), NULL, 0);
+				drv_id, pa, size, NULL, 0);
 	if (ret == -ENOMEM) {
 		mem = (void *)__get_free_page(GFP_KERNEL);
 		if (!mem)
 			return -ENOMEM;
 
 		ret = kvm_call_hyp_nvhe(__pkvm_iommu_register, dev_to_id(dev),
-					drv_id, pa, size, dev_to_id(parent),
-					mem, PAGE_SIZE);
+					drv_id, pa, size, mem, PAGE_SIZE);
 	}
 	return ret;
 }

arch/arm64/kvm/iommu/s2mpu.c

@@ -81,6 +81,6 @@ int pkvm_iommu_s2mpu_register(struct device *dev, phys_addr_t addr)
 		return ret;
 
 	return pkvm_iommu_register(dev, PKVM_IOMMU_DRIVER_S2MPU,
-				   addr, S2MPU_MMIO_SIZE, NULL);
+				   addr, S2MPU_MMIO_SIZE);
 }
 EXPORT_SYMBOL_GPL(pkvm_iommu_s2mpu_register);