[PATCH v8 2/5] ACPI/IORT: Add msi address regions reservation helper

[Marc Zyngier]

On 27/09/17 14:32, Shameer Kolothum wrote:
> On some platforms msi parent address regions have to be excluded from
> normal IOVA allocation in that they are detected and decoded in a HW
> specific way by system components and so they cannot be considered normal
> IOVA address space.
> 
> Add a helper function that retrieves ITS address regions - the msi
> parent - through IORT device <-> ITS mappings and reserves it so that
> these regions will not be translated by IOMMU and will be excluded from
> IOVA allocations.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
> [lorenzo.pieralisi at arm.com: updated commit log/added comments]
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> ---
>  drivers/acpi/arm64/iort.c        | 96 ++++++++++++++++++++++++++++++++++++++--
>  drivers/irqchip/irq-gic-v3-its.c |  3 +-
>  include/linux/acpi_iort.h        |  7 ++-
>  3 files changed, 101 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 9565d57..14efa9d 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -39,6 +39,7 @@
>  struct iort_its_msi_chip {
>  	struct list_head	list;
>  	struct fwnode_handle	*fw_node;
> +	phys_addr_t		base_addr;
>  	u32			translation_id;
>  };
>  
> @@ -136,14 +137,16 @@ typedef acpi_status (*iort_find_node_callback)
>  static DEFINE_SPINLOCK(iort_msi_chip_lock);
>  
>  /**
> - * iort_register_domain_token() - register domain token and related ITS ID
> - * to the list from where we can get it back later on.
> + * iort_register_domain_token() - register domain token along with related
> + * ITS ID and base address to the list from where we can get it back later on.
>   * @trans_id: ITS ID.
> + * @base: ITS base address.
>   * @fw_node: Domain token.
>   *
>   * Returns: 0 on success, -ENOMEM if no memory when allocating list element
>   */
> -int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
> +int iort_register_domain_token(int trans_id, phys_addr_t base,
> +			       struct fwnode_handle *fw_node)
>  {
>  	struct iort_its_msi_chip *its_msi_chip;
>  
> @@ -153,6 +156,7 @@ int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
>  
>  	its_msi_chip->fw_node = fw_node;
>  	its_msi_chip->translation_id = trans_id;
> +	its_msi_chip->base_addr = base;
>  
>  	spin_lock(&iort_msi_chip_lock);
>  	list_add(&its_msi_chip->list, &iort_msi_chip_list);
> @@ -481,6 +485,24 @@ int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
>  	return -ENODEV;
>  }
>  
> +static int __maybe_unused iort_find_its_base(u32 its_id, phys_addr_t *base)
> +{
> +	struct iort_its_msi_chip *its_msi_chip;
> +	bool match = false;
> +
> +	spin_lock(&iort_msi_chip_lock);
> +	list_for_each_entry(its_msi_chip, &iort_msi_chip_list, list) {
> +		if (its_msi_chip->translation_id == its_id) {
> +			*base = its_msi_chip->base_addr;
> +			match = true;
> +			break;
> +		}
> +	}
> +	spin_unlock(&iort_msi_chip_lock);
> +
> +	return match ? 0 : -ENODEV;
> +}
> +
>  /**
>   * iort_dev_find_its_id() - Find the ITS identifier for a device
>   * @dev: The device.
> @@ -639,6 +661,72 @@ int iort_add_device_replay(const struct iommu_ops *ops, struct device *dev)
>  
>  	return err;
>  }
> +
> +/**
> + * iort_iommu_msi_get_resv_regions - Reserved region driver helper
> + * @dev: Device from iommu_get_resv_regions()
> + * @head: Reserved region list from iommu_get_resv_regions()
> + *
> + * Returns: Number of reserved regions on success (0 if no associated msi
> + *          regions), appropriate error value otherwise. The ITS regions
> + *          associated with the device are the msi reserved regions.
> + */
> +int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
> +{
> +	struct acpi_iort_its_group *its;
> +	struct acpi_iort_node *node, *its_node = NULL;
> +	int i, resv = 0;
> +
> +	node = iort_find_dev_node(dev);
> +	if (!node)
> +		return -ENODEV;
> +
> +	/*
> +	 * Current logic to reserve ITS regions relies on HW topologies
> +	 * where a given PCI or named component maps its IDs to only one
> +	 * ITS group; if a PCI or named component can map its IDs to
> +	 * different ITS groups through IORT mappings this function has
> +	 * to be reworked to ensure we reserve regions for all ITS groups
> +	 * a given PCI or named component may map IDs to.
> +	 */
> +	if (dev_is_pci(dev)) {
> +		u32 rid;
> +
> +		pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid, &rid);
> +		its_node = iort_node_map_id(node, rid, NULL, IORT_MSI_TYPE);
> +	} else {
> +		for (i = 0; i < node->mapping_count; i++) {
> +			its_node = iort_node_map_platform_id(node, NULL,
> +							 IORT_MSI_TYPE, i);
> +			if (its_node)
> +				break;
> +		}
> +	}
> +
> +	if (!its_node)
> +		return 0;
> +
> +	/* Move to ITS specific data */
> +	its = (struct acpi_iort_its_group *)its_node->node_data;
> +
> +	for (i = 0; i < its->its_count; i++) {
> +		phys_addr_t base;
> +
> +		if (!iort_find_its_base(its->identifiers[i], &base)) {
> +			int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
> +			struct iommu_resv_region *region;
> +
> +			region = iommu_alloc_resv_region(base, SZ_128K, prot,
> +							 IOMMU_RESV_MSI);

Same as the OF part: I strongly object to reserving the whole 128kB
range. What we really care about is the second 64kB page, and that is
what should get reserved.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...