x86/amd-iommu: Add an index field to struct amd_iommu

This patch adds an index field to struct amd_iommu which can
be used to lookup it up in an array. This index will be used
in struct protection_domain to keep track which protection
domain has devices behind which IOMMU.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index df5e9c8a856a..ab3e7bf1af71 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -25,6 +25,11 @@
 #include <linux/spinlock.h>
 
 /*
+ * Maximum number of IOMMUs supported
+ */
+#define MAX_IOMMUS      32
+
+/*
  * some size calculation constants
  */
 #define DEV_TABLE_ENTRY_SIZE            32
@@ -291,6 +296,9 @@ struct dma_ops_domain {
 struct amd_iommu {
         struct list_head list;
 
+        /* Index within the IOMMU array */
+        int index;
+
         /* locks the accesses to the hardware */
         spinlock_t lock;
 
@@ -357,6 +365,15 @@ struct amd_iommu {
 extern struct list_head amd_iommu_list;
 
 /*
+ * Array with pointers to each IOMMU struct
+ * The indices are referenced in the protection domains
+ */
+extern struct amd_iommu *amd_iommus[MAX_IOMMUS];
+
+/* Number of IOMMUs present in the system */
+extern int amd_iommus_present;
+
+/*
  * Structure defining one entry in the device table
  */
 struct dev_table_entry {
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index cee11424d412..8567d1698027 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -137,6 +137,10 @@ bool amd_iommu_unmap_flush;		/* if true, flush on every unmap */
 LIST_HEAD(amd_iommu_list);              /* list of all AMD IOMMUs in the
                                            system */
 
+/* Array to assign indices to IOMMUs*/
+struct amd_iommu *amd_iommus[MAX_IOMMUS];
+int amd_iommus_present;
+
 /*
  * Pointer to the device table which is shared by all AMD IOMMUs
  * it is indexed by the PCI device id or the HT unit id and contains
@@ -840,7 +844,18 @@ static void __init free_iommu_all(void)
 static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
 {
         spin_lock_init(&iommu->lock);
+
+        /* Add IOMMU to internal data structures */
         list_add_tail(&iommu->list, &amd_iommu_list);
+        iommu->index             = amd_iommus_present++;
+
+        if (unlikely(iommu->index >= MAX_IOMMUS)) {
+                WARN(1, "AMD-Vi: System has more IOMMUs than supported by this driver\n");
+                return -ENOSYS;
+        }
+
+        /* Index is fine - add IOMMU to the array */
+        amd_iommus[iommu->index] = iommu;
 
         /*
          * Copy data from ACPI table entry to the iommu struct