[Patch Part3 V4 15/21] iommu/vt-d: Dynamically allocate and free seq_id for DMAR units

Jiang Liu
2014-07-11T06:20:59Z

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>
---
drivers/iommu/dmar.c | 40 ++++++++++++++++++++++++++++++++++------
drivers/iommu/intel-iommu.c | 13 +++----------
include/linux/dmar.h | 6 ++++++
3 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 4fdf238a2a28..02a769347fcb 100644
--- 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);
@@ -929,11 +930,32 @@ 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;
@@ -947,13 +969,16 @@ 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;
@@ -1003,9 +1028,11 @@ 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;
}
@@ -1029,6 +1056,7 @@ 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 d0c37d59e6be..9c5eacc28b0e 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -328,17 +328,10 @@ 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 */
@@ -2704,12 +2697,12 @@ 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 fac8ca34f9a8..c8a576bc3a98 100644
--- 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
--
1.7.10.4