[RFC PATCH 03/36] iommu/amd: Introduce per PCI segment rlookup table

[Vasant Hegde via iommu <iommu@lists.linux-foundation.org>]

From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>

This will replace global rlookup table (amd_iommu_rlookup_table).
Also add helper functions to set/get rlookup table for the given device.

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>
---
 drivers/iommu/amd/amd_iommu.h       |  1 +
 drivers/iommu/amd/amd_iommu_types.h |  8 ++++++
 drivers/iommu/amd/init.c            | 23 +++++++++++++++
 drivers/iommu/amd/iommu.c           | 44 +++++++++++++++++++++++++++++
 4 files changed, 76 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index fa9a4eac45de..4c22683011cf 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -16,6 +16,7 @@ extern irqreturn_t amd_iommu_int_handler(int irq, void *data);
 extern void amd_iommu_apply_erratum_63(u16 devid);
 extern void amd_iommu_restart_event_logging(struct amd_iommu *iommu);
 extern int amd_iommu_init_api(void);
+extern void amd_iommu_set_rlookup_table(struct amd_iommu *iommu, u16 devid);
 
 #ifdef CONFIG_AMD_IOMMU_DEBUGFS
 void amd_iommu_debugfs_setup(struct amd_iommu *iommu);
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 90d3a953bf97..0eeac1d23786 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -486,6 +486,7 @@ struct amd_iommu_fault {
 };
 
 
+struct amd_iommu;
 struct iommu_domain;
 struct irq_domain;
 struct amd_irte_ops;
@@ -549,6 +550,13 @@ struct amd_iommu_pci_seg {
 	 * page table root pointer.
 	 */
 	struct dev_table_entry *dev_table;
+
+	/*
+	 * The rlookup iommu table is used to find the IOMMU which is
+	 * responsible for a specific device. It is indexed by the PCI
+	 * device id.
+	 */
+	struct amd_iommu **rlookup_table;
 };
 
 /*
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 0fd1071bfc85..a2efc02ba80a 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -663,6 +663,26 @@ static inline void free_dev_table(struct amd_iommu_pci_seg *pci_seg)
 	pci_seg->dev_table = NULL;
 }
 
+/* Allocate per PCI segment IOMMU rlookup table. */
+static inline int __init alloc_rlookup_table(struct amd_iommu_pci_seg *pci_seg)
+{
+	pci_seg->rlookup_table = (void *)__get_free_pages(
+						GFP_KERNEL | __GFP_ZERO,
+						get_order(rlookup_table_size));
+	if (pci_seg->rlookup_table == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static inline void free_rlookup_table(struct amd_iommu_pci_seg *pci_seg)
+{
+	free_pages((unsigned long)pci_seg->rlookup_table,
+		   get_order(rlookup_table_size));
+	pci_seg->rlookup_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
@@ -1489,6 +1509,8 @@ static struct amd_iommu_pci_seg *__init alloc_pci_segment(u16 id)
 
 	if (alloc_dev_table(pci_seg))
 		return NULL;
+	if (alloc_rlookup_table(pci_seg))
+		return NULL;
 
 	return pci_seg;
 }
@@ -1511,6 +1533,7 @@ static void __init free_pci_segment(void)
 
 	for_each_pci_segment_safe(pci_seg, next) {
 		list_del(&pci_seg->list);
+		free_rlookup_table(pci_seg);
 		free_dev_table(pci_seg);
 		kfree(pci_seg);
 	}
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index bf607cce3234..fa473ee5be28 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -146,6 +146,50 @@ struct dev_table_entry *get_dev_table(struct amd_iommu *iommu)
 	return dev_table;
 }
 
+static inline u16 get_device_segment(struct device *dev)
+{
+	u16 seg;
+
+	if (dev_is_pci(dev)) {
+		struct pci_dev *pdev = to_pci_dev(dev);
+
+		seg = pci_domain_nr(pdev->bus);
+	} else {
+		u32 devid = get_acpihid_device_id(dev, NULL);
+
+		seg = (devid >> 16) & 0xffff;
+	}
+
+	return seg;
+}
+
+/* Writes the specific IOMMU for a device into the PCI segment rlookup table */
+void amd_iommu_set_rlookup_table(struct amd_iommu *iommu, u16 devid)
+{
+	struct amd_iommu_pci_seg *pci_seg = iommu->pci_seg;
+
+	pci_seg->rlookup_table[devid] = iommu;
+}
+
+static struct amd_iommu *__rlookup_amd_iommu(u16 seg, u16 devid)
+{
+	struct amd_iommu_pci_seg *pci_seg;
+
+	for_each_pci_segment(pci_seg) {
+		if (pci_seg->id == seg)
+			return pci_seg->rlookup_table[devid];
+	}
+	return NULL;
+}
+
+static struct amd_iommu *rlookup_amd_iommu(struct device *dev)
+{
+	u16 seg = get_device_segment(dev);
+	u16 devid = get_device_id(dev);
+
+	return __rlookup_amd_iommu(seg, devid);
+}
+
 static struct protection_domain *to_pdomain(struct iommu_domain *dom)
 {
 	return container_of(dom, struct protection_domain, domain);
-- 
2.27.0

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