iommu/vt-d: Dynamically allocate and free seq_id for DMAR units

Introduce functions to support dynamic IOMMU seq_id allocating and
releasing, which will be used to support DMAR hotplug.

Also rename IOMMU_UNITS_SUPPORTED as DMAR_UNITS_SUPPORTED.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Reviewed-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 586dd2a..78aa1b2 100644 (file)
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -70,6 +70,7 @@ LIST_HEAD(dmar_drhd_units);
 struct acpi_table_header * __initdata dmar_tbl;
 static acpi_size dmar_tbl_size;
 static int dmar_dev_scope_status = 1;
+static unsigned long dmar_seq_ids[BITS_TO_LONGS(DMAR_UNITS_SUPPORTED)];
 
 static int alloc_iommu(struct dmar_drhd_unit *drhd);
 static void free_iommu(struct intel_iommu *iommu);
@@ -944,11 +945,32 @@ out:
        return err;
 }
 
+static int dmar_alloc_seq_id(struct intel_iommu *iommu)
+{
+       iommu->seq_id = find_first_zero_bit(dmar_seq_ids,
+                                           DMAR_UNITS_SUPPORTED);
+       if (iommu->seq_id >= DMAR_UNITS_SUPPORTED) {
+               iommu->seq_id = -1;
+       } else {
+               set_bit(iommu->seq_id, dmar_seq_ids);
+               sprintf(iommu->name, "dmar%d", iommu->seq_id);
+       }
+
+       return iommu->seq_id;
+}
+
+static void dmar_free_seq_id(struct intel_iommu *iommu)
+{
+       if (iommu->seq_id >= 0) {
+               clear_bit(iommu->seq_id, dmar_seq_ids);
+               iommu->seq_id = -1;
+       }
+}
+
 static int alloc_iommu(struct dmar_drhd_unit *drhd)
 {
        struct intel_iommu *iommu;
        u32 ver, sts;
-       static int iommu_allocated = 0;
        int agaw = 0;
        int msagaw = 0;
        int err;
@@ -962,13 +984,16 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
        if (!iommu)
                return -ENOMEM;
 
-       iommu->seq_id = iommu_allocated++;
-       sprintf (iommu->name, "dmar%d", iommu->seq_id);
+       if (dmar_alloc_seq_id(iommu) < 0) {
+               pr_err("IOMMU: failed to allocate seq_id\n");
+               err = -ENOSPC;
+               goto error;
+       }
 
        err = map_iommu(iommu, drhd->reg_base_addr);
        if (err) {
                pr_err("IOMMU: failed to map %s\n", iommu->name);
-               goto error;
+               goto error_free_seq_id;
        }
 
        err = -EINVAL;
@@ -1018,9 +1043,11 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 
        return 0;
 
- err_unmap:
+err_unmap:
        unmap_iommu(iommu);
- error:
+error_free_seq_id:
+       dmar_free_seq_id(iommu);
+error:
        kfree(iommu);
        return err;
 }
@@ -1044,6 +1071,7 @@ static void free_iommu(struct intel_iommu *iommu)
        if (iommu->reg)
                unmap_iommu(iommu);
 
+       dmar_free_seq_id(iommu);
        kfree(iommu);
 }
 

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index b9cc9c2..2779354 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -330,17 +330,10 @@ static int hw_pass_through = 1;
 /* si_domain contains mulitple devices */
 #define DOMAIN_FLAG_STATIC_IDENTITY    (1 << 1)
 
-/* define the limit of IOMMUs supported in each domain */
-#ifdef CONFIG_X86
-# define       IOMMU_UNITS_SUPPORTED   MAX_IO_APICS
-#else
-# define       IOMMU_UNITS_SUPPORTED   64
-#endif
-
 struct dmar_domain {
        int     id;                     /* domain id */
        int     nid;                    /* node id */
-       DECLARE_BITMAP(iommu_bmp, IOMMU_UNITS_SUPPORTED);
+       DECLARE_BITMAP(iommu_bmp, DMAR_UNITS_SUPPORTED);
                                        /* bitmap of iommus this domain uses*/
 
        struct list_head devices;       /* all devices' list */
@@ -2730,12 +2723,12 @@ static int __init init_dmars(void)
                 * threaded kernel __init code path all other access are read
                 * only
                 */
-               if (g_num_of_iommus < IOMMU_UNITS_SUPPORTED) {
+               if (g_num_of_iommus < DMAR_UNITS_SUPPORTED) {
                        g_num_of_iommus++;
                        continue;
                }
                printk_once(KERN_ERR "intel-iommu: exceeded %d IOMMUs\n",
-                         IOMMU_UNITS_SUPPORTED);
+                         DMAR_UNITS_SUPPORTED);
        }
 
        g_iommus = kcalloc(g_num_of_iommus, sizeof(struct intel_iommu *),

diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 495df5e..725204f 100644 (file)
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -30,6 +30,12 @@
 
 struct acpi_dmar_header;
 
+#ifdef CONFIG_X86
+# define       DMAR_UNITS_SUPPORTED    MAX_IO_APICS
+#else
+# define       DMAR_UNITS_SUPPORTED    64
+#endif
+
 /* DMAR Flags */
 #define DMAR_INTR_REMAP                0x1
 #define DMAR_X2APIC_OPT_OUT    0x2