int amd_iommu_init_device()

in amd/iommu_v2.c [732:827]

• 66 lines of code
• 12 McCabe index (conditional complexity)

int amd_iommu_init_device(struct pci_dev *pdev, int pasids)
{
	struct device_state *dev_state;
	struct iommu_group *group;
	unsigned long flags;
	int ret, tmp;
	u16 devid;

	might_sleep();

	/*
	 * When memory encryption is active the device is likely not in a
	 * direct-mapped domain. Forbid using IOMMUv2 functionality for now.
	 */
	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
		return -ENODEV;

	if (!amd_iommu_v2_supported())
		return -ENODEV;

	if (pasids <= 0 || pasids > (PASID_MASK + 1))
		return -EINVAL;

	devid = device_id(pdev);

	dev_state = kzalloc(sizeof(*dev_state), GFP_KERNEL);
	if (dev_state == NULL)
		return -ENOMEM;

	spin_lock_init(&dev_state->lock);
	init_waitqueue_head(&dev_state->wq);
	dev_state->pdev  = pdev;
	dev_state->devid = devid;

	tmp = pasids;
	for (dev_state->pasid_levels = 0; (tmp - 1) & ~0x1ff; tmp >>= 9)
		dev_state->pasid_levels += 1;

	atomic_set(&dev_state->count, 1);
	dev_state->max_pasids = pasids;

	ret = -ENOMEM;
	dev_state->states = (void *)get_zeroed_page(GFP_KERNEL);
	if (dev_state->states == NULL)
		goto out_free_dev_state;

	dev_state->domain = iommu_domain_alloc(&pci_bus_type);
	if (dev_state->domain == NULL)
		goto out_free_states;

	amd_iommu_domain_direct_map(dev_state->domain);

	ret = amd_iommu_domain_enable_v2(dev_state->domain, pasids);
	if (ret)
		goto out_free_domain;

	group = iommu_group_get(&pdev->dev);
	if (!group) {
		ret = -EINVAL;
		goto out_free_domain;
	}

	ret = iommu_attach_group(dev_state->domain, group);
	if (ret != 0)
		goto out_drop_group;

	iommu_group_put(group);

	spin_lock_irqsave(&state_lock, flags);

	if (__get_device_state(devid) != NULL) {
		spin_unlock_irqrestore(&state_lock, flags);
		ret = -EBUSY;
		goto out_free_domain;
	}

	list_add_tail(&dev_state->list, &state_list);

	spin_unlock_irqrestore(&state_lock, flags);

	return 0;

out_drop_group:
	iommu_group_put(group);

out_free_domain:
	iommu_domain_free(dev_state->domain);

out_free_states:
	free_page((unsigned long)dev_state->states);

out_free_dev_state:
	kfree(dev_state);

	return ret;
}