On 8/5/2021 7:03 PM, Lorenzo Pieralisi wrote:

On Thu, Aug 05, 2021 at 09:07:17AM +0100, Shameer Kolothum wrote:

[...]

quoted

+static void __init iort_node_get_rmr_info(struct acpi_iort_node *iort_node)
+{
+	struct acpi_iort_node *smmu;
+	struct acpi_iort_rmr *rmr;
+	struct acpi_iort_rmr_desc *rmr_desc;
+	u32 map_count = iort_node->mapping_count;
+	u32 sid;
+	int i;
+
+	if (!iort_node->mapping_offset || map_count != 1) {
+		pr_err(FW_BUG "Invalid ID mapping, skipping RMR node %p\n",
+		       iort_node);
+		return;
+	}
+
+	/* Retrieve associated smmu and stream id */
+	smmu = iort_node_get_id(iort_node, &sid, 0);
+	if (!smmu) {
+		pr_err(FW_BUG "Invalid SMMU reference, skipping RMR node %p\n",
+		       iort_node);
+		return;
+	}
+
+	/* Retrieve RMR data */
+	rmr = (struct acpi_iort_rmr *)iort_node->node_data;
+	if (!rmr->rmr_offset || !rmr->rmr_count) {
+		pr_err(FW_BUG "Invalid RMR descriptor array, skipping RMR node %p\n",
+		       iort_node);
+		return;
+	}
+
+	rmr_desc = ACPI_ADD_PTR(struct acpi_iort_rmr_desc, iort_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;
+		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 & IOMMU_RMR_REMAP_PERMITTED) {
+			type = IOMMU_RESV_DIRECT_RELAXABLE;
+			/*
+			 * Set IOMMU_CACHE as IOMMU_RESV_DIRECT_RELAXABLE is
+			 * normally used for allocated system memory that is
+			 * then used for device specific reserved regions.
+			 */
+			prot |= IOMMU_CACHE;
+		} else {
+			type = IOMMU_RESV_DIRECT;
+			/*
+			 * Set IOMMU_MMIO as IOMMU_RESV_DIRECT is normally used
+			 * for device memory like MSI doorbell.
+			 */
+			prot |= IOMMU_MMIO;
+		}

On the prot value assignment based on the remapping flag, I'd like to
hear Robin/Joerg's opinion, I'd avoid being in a situation where
"normally" this would work but then we have to quirk it.

Is this a valid assumption _always_ ?

I think we enable quite a bit of platforms with this assumption, so IMHO
it's a fair compromise for now. As per Jon's comment and oob
discussions, in the long run the spec should probably be updated to
include a way of explicitly specifying memory attributes.

---
Thanks & Best Regards, Laurentiu

quoted

+
+		region = iommu_alloc_resv_region(addr, size, prot, type);
+		if (region) {
+			region->fw_data.rmr.flags = rmr->flags;
+			region->fw_data.rmr.sid = sid;
+			region->fw_data.rmr.smmu = smmu;
+			list_add_tail(&region->list, &iort_rmr_list);
+		}
+	}
+}
+
+static void __init iort_parse_rmr(void)
+{
+	struct acpi_iort_node *iort_node, *iort_end;
+	struct acpi_table_iort *iort;
+	int i;
+
+	if (iort_table->revision < 3)
+		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);
+
+		iort_node = ACPI_ADD_PTR(struct acpi_iort_node, iort_node,
+					 iort_node->length);
+	}
+}
 
 static void __init iort_init_platform_devices(void)
 {

@@ -1636,6 +1767,7 @@ void __init acpi_iort_init(void)
 	}
 
 	iort_init_platform_devices();
+	iort_parse_rmr();
 }
 
 #ifdef CONFIG_ZONE_DMA

-- 
2.17.1

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