iommu/amd: Introduce per PCI segment device table

Introduce per PCI segment device table. All IOMMUs within the segment
will share this device table. This will replace global device
table i.e. amd_iommu_dev_table.

Also introduce helper function to get the device table for the given IOMMU.

Co-developed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20220706113825.25582-4-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd/amd_iommu.h

@@ -128,4 +128,5 @@ static inline void amd_iommu_apply_ivrs_quirks(void) { }
 
 extern void amd_iommu_domain_set_pgtable(struct protection_domain *domain,
 					 u64 *root, int mode);
+extern struct dev_table_entry *get_dev_table(struct amd_iommu *iommu);
 #endif

drivers/iommu/amd/amd_iommu_types.h

@@ -544,6 +544,16 @@ struct amd_iommu_pci_seg {
 
 	/* PCI segment number */
 	u16 id;
+
+	/*
+	 * device table virtual address
+	 *
+	 * Pointer to the per PCI segment device table.
+	 * It is indexed by the PCI device id or the HT unit id and contains
+	 * information about the domain the device belongs to as well as the
+	 * page table root pointer.
+	 */
+	struct dev_table_entry *dev_table;
 };
 
 /*

drivers/iommu/amd/init.c

@@ -642,11 +642,29 @@ static int __init find_last_devid_acpi(struct acpi_table_header *table)
  *
  * The following functions belong to the code path which parses the ACPI table
  * the second time. In this ACPI parsing iteration we allocate IOMMU specific
- * data structures, initialize the device/alias/rlookup table and also
+ * data structures, initialize the per PCI segment device/alias/rlookup table
- * basically initialize the hardware.
+ * and also basically initialize the hardware.
  *
  ****************************************************************************/
 
+/* Allocate per PCI segment device table */
+static inline int __init alloc_dev_table(struct amd_iommu_pci_seg *pci_seg)
+{
+	pci_seg->dev_table = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO | GFP_DMA32,
+						      get_order(dev_table_size));
+	if (!pci_seg->dev_table)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static inline void free_dev_table(struct amd_iommu_pci_seg *pci_seg)
+{
+	free_pages((unsigned long)pci_seg->dev_table,
+		    get_order(dev_table_size));
+	pci_seg->dev_table = NULL;
+}
+
 /*
  * Allocates the command buffer. This buffer is per AMD IOMMU. We can
  * write commands to that buffer later and the IOMMU will execute them
@@ -1471,6 +1489,9 @@ static struct amd_iommu_pci_seg *__init alloc_pci_segment(u16 id)
 	pci_seg->id = id;
 	list_add_tail(&pci_seg->list, &amd_iommu_pci_seg_list);
 
+	if (alloc_dev_table(pci_seg))
+		return NULL;
+
 	return pci_seg;
 }
 
@@ -1492,6 +1513,7 @@ static void __init free_pci_segments(void)
 
 	for_each_pci_segment_safe(pci_seg, next) {
 		list_del(&pci_seg->list);
+		free_dev_table(pci_seg);
 		kfree(pci_seg);
 	}
 }

drivers/iommu/amd/iommu.c

@@ -134,6 +134,18 @@ static inline int get_device_id(struct device *dev)
 	return devid;
 }
 
+struct dev_table_entry *get_dev_table(struct amd_iommu *iommu)
+{
+	struct dev_table_entry *dev_table;
+	struct amd_iommu_pci_seg *pci_seg = iommu->pci_seg;
+
+	BUG_ON(pci_seg == NULL);
+	dev_table = pci_seg->dev_table;
+	BUG_ON(dev_table == NULL);
+
+	return dev_table;
+}
+
 static struct protection_domain *to_pdomain(struct iommu_domain *dom)
 {
 	return container_of(dom, struct protection_domain, domain);