Re: [PATCH v8 03/11] ACPI/IORT: Add helper functions to parse RMR nodes

Eric Auger
2022-03-10T10:32:43Z

Hi Shameer,

On 2/21/22 4:43 PM, Shameer Kolothum wrote:
> The helper functions here parse through the IORT RMR nodes and
> populate a reserved region list corresponding to a given iommu
> and device(optional). These also go through the ID mappings of
> the RMR node and retrieves all the SIDs associated with a RMR
> descriptor.
>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
> drivers/acpi/arm64/iort.c | 225 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 225 insertions(+)
>
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 0730c4dbb700..05da9ebff50a 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -830,6 +830,231 @@ static struct acpi_iort_node *iort_get_msi_resv_iommu(struct device *dev)
> return NULL;
> }
>
> +static void iort_rmr_desc_check_overlap(struct acpi_iort_rmr_desc *desc, u32 count)
> +{
> + int i, j;
> +
> + for (i = 0; i < count; i++) {
> + u64 end, start = desc[i].base_address, length = desc[i].length;
> +
> + end = start + length - 1;
> +
> + /* Check for address overlap */
> + for (j = i + 1; j < count; j++) {
> + u64 e_start = desc[j].base_address;
> + u64 e_end = e_start + desc[j].length - 1;
> +
> + if (start <= e_end && end >= e_start)
> + pr_err(FW_BUG "RMR descriptor[0x%llx - 0x%llx] overlaps, continue anyway\n",
> + start, end);
> + }
> + }
> +}
> +
> +/*
> + * Please note, we will keep the already allocated RMR reserve
> + * regions in case of a memory allocation failure.
> + */
> +static void iort_rmr_get_resv_regions(struct acpi_iort_node *node,
> + struct acpi_iort_node *smmu,
> + u32 *sids, u32 num_sids,
> + struct list_head *head)
> +{
> + struct acpi_iort_rmr *rmr = (struct acpi_iort_rmr *)node->node_data;
> + struct acpi_iort_rmr_desc *rmr_desc;
> + int i;
> +
> + rmr_desc = ACPI_ADD_PTR(struct acpi_iort_rmr_desc, node,
> + rmr->rmr_offset);
> +
> + iort_rmr_desc_check_overlap(rmr_desc, rmr->rmr_count);
> +
> + for (i = 0; i < rmr->rmr_count; i++, rmr_desc++) {
> + struct iommu_resv_region *region;
> + enum iommu_resv_type type;
> + u32 *sids_copy;
> + int prot = IOMMU_READ | IOMMU_WRITE;
> + u64 addr = rmr_desc->base_address, size = rmr_desc->length;
> +
> + if (!IS_ALIGNED(addr, SZ_64K) || !IS_ALIGNED(size, SZ_64K)) {
> + /* PAGE align base addr and size */
> + addr &= PAGE_MASK;
> + size = PAGE_ALIGN(size + offset_in_page(rmr_desc->base_address));
> +
> + pr_err(FW_BUG "RMR descriptor[0x%llx - 0x%llx] not aligned to 64K, continue with [0x%llx - 0x%llx]\n",
> + rmr_desc->base_address,
> + rmr_desc->base_address + rmr_desc->length - 1,
> + addr, addr + size - 1);
> + }
> +
> + if (rmr->flags & ACPI_IORT_RMR_REMAP_PERMITTED)
> + type = IOMMU_RESV_DIRECT_RELAXABLE;
> + else
> + type = IOMMU_RESV_DIRECT;
> +
> + if (rmr->flags & ACPI_IORT_RMR_ACCESS_PRIVILEGE)
> + prot |= IOMMU_PRIV;
> +
> + /* Attributes 0x00 - 0x03 represents device memory */
> + if (ACPI_IORT_RMR_ACCESS_ATTRIBUTES(rmr->flags) <=
> + ACPI_IORT_RMR_ATTR_DEVICE_GRE)
> + prot |= IOMMU_MMIO;
> + else if (ACPI_IORT_RMR_ACCESS_ATTRIBUTES(rmr->flags) ==
> + ACPI_IORT_RMR_ATTR_NORMAL)
> + prot |= IOMMU_CACHE;
> +
> + /* Create a copy of sids array to associate with this resv region */
> + sids_copy = kmemdup(sids, num_sids * sizeof(*sids), GFP_KERNEL);
> + if (!sids_copy)
> + return;
> +
> + region = iommu_alloc_resv_region(addr, size, prot, type);
> + if (!region) {
> + kfree(sids_copy);
> + return;
> + }
> +
> + region->fw_data.rmr.sids = sids_copy;
> + region->fw_data.rmr.num_sids = num_sids;
> + list_add_tail(&region->list, head);
> + }
> +}
> +
> +static u32 *iort_rmr_alloc_sids(u32 *sids, u32 count, u32 id_start,
> + u32 new_count)
> +{
> + u32 *new_sids;
> + u32 total_count = count + new_count;
> + int i;
> +
> + new_sids = krealloc_array(sids, count + new_count,
> + sizeof(*new_sids), GFP_KERNEL);
> + if (!new_sids)
> + return NULL;
> +
> + /*Update new ones */
> + for (i = count; i < total_count; i++)
> + new_sids[i] = id_start++;
> +
> + return new_sids;
> +}
> +
> +static bool iort_rmr_has_dev(struct device *dev, u32 id_start,
> + u32 id_count)
> +{
> + int i;
> + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> +
> + if (dev_is_pci(dev)) {
> + struct pci_dev *pdev = to_pci_dev(dev);
> + struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
> +
> + if (!host->preserve_config)
> + return false;
> + }
> +
> + for (i = 0; i < fwspec->num_ids; i++) {
> + if (fwspec->ids[i] >= id_start &&
> + fwspec->ids[i] <= id_start + id_count)
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static void iort_node_get_rmr_info(struct acpi_iort_node *node,
> + struct acpi_iort_node *iommu,
> + struct device *dev, struct list_head *head)
> +{
> + struct acpi_iort_node *smmu = NULL;
> + struct acpi_iort_rmr *rmr;
> + struct acpi_iort_id_mapping *map;
> + u32 *sids = NULL;
> + u32 num_sids = 0;
> + int i;
> +
> + if (!node->mapping_offset || !node->mapping_count) {
> + pr_err(FW_BUG "Invalid ID mapping, skipping RMR node %p\n",
> + node);
> + return;
> + }
> +
> + rmr = (struct acpi_iort_rmr *)node->node_data;
> + if (!rmr->rmr_offset || !rmr->rmr_count)
> + return;
> +
> + map = ACPI_ADD_PTR(struct acpi_iort_id_mapping, node,
> + node->mapping_offset);
> +
> + /*
> + * Go through the ID mappings and see if we have a match
> + * for smmu and dev(if !NULL). If found, get the sids
> + * for the Node.
> + * Please note, id_count is equal to the number of IDs
> + * in the range minus one.
> + */
> + for (i = 0; i < node->mapping_count; i++, map++) {
> + struct acpi_iort_node *parent;
> +
> + if (!map->id_count)
> + continue;
> +
> + parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
> + map->output_reference);
> + if (parent != iommu)
> + continue;
> +
> + /* If dev is valid, check RMR node corresponds to the dev sid */
> + if (dev && !iort_rmr_has_dev(dev, map->output_base,
> + map->id_count))
> + continue;
> +
> + /* Retrieve sids associated with the Node. */
> + sids = iort_rmr_alloc_sids(sids, num_sids, map->output_base,
> + map->id_count + 1);
> + if (!sids)
> + return;
> +
> + num_sids += map->id_count + 1;
> + }
> +
> + if (!sids)
> + return;
> +
> + iort_rmr_get_resv_regions(node, smmu, sids, num_sids, head);
> + kfree(sids);
> +}
> +
> +static void iort_find_rmrs(struct acpi_iort_node *iommu, struct device *dev,
> + struct list_head *head)
> +{
> + struct acpi_table_iort *iort;
> + struct acpi_iort_node *iort_node, *iort_end;
> + int i;
> +
> + if (iort_table->revision < 5)
This means E.b and E.c revs are not supported. Is it what we want?

Thanks

Eric
> + return;
> +
> + iort = (struct acpi_table_iort *)iort_table;
> +
> + iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort,
> + iort->node_offset);
> + iort_end = ACPI_ADD_PTR(struct acpi_iort_node, iort,
> + iort_table->length);
> +
> + for (i = 0; i < iort->node_count; i++) {
> + if (WARN_TAINT(iort_node >= iort_end, TAINT_FIRMWARE_WORKAROUND,
> + "IORT node pointer overflows, bad table!\n"))
> + return;
> +
> + if (iort_node->type == ACPI_IORT_NODE_RMR)
> + iort_node_get_rmr_info(iort_node, iommu, dev, head);
> +
> + iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
> + iort_node->length);
> + }
> +}
> +
> /**
> * iort_iommu_msi_get_resv_regions - Reserved region driver helper
> * @dev: Device from iommu_get_resv_regions()