[PATCH v9 8/8] perf/amd/iommu: Enable support for multiple IOMMUs

[Suravee Suthikulpanit]

From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

Add multi-IOMMU support for perf by exposing an AMD IOMMU PMU
for each IOMMU found in the system via:

  /bus/event_source/devices/amd_iommu_x

where x is the IOMMU index. This allows users to specify
different events to be programmed onto performance counters
of each IOMMU.

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
---
 arch/x86/events/amd/iommu.c | 108 ++++++++++++++++++++++++++------------------
 1 file changed, 64 insertions(+), 44 deletions(-)

diff --git a/arch/x86/events/amd/iommu.c b/arch/x86/events/amd/iommu.c
index 7bbf405..d9313d2 100644
--- a/arch/x86/events/amd/iommu.c
+++ b/arch/x86/events/amd/iommu.c
@@ -35,16 +35,21 @@
 #define _GET_PASID_MASK(ev) ((ev->hw.extra_reg.config >> 16) & 0xFFFFULL)
 #define _GET_DOMID_MASK(ev) ((ev->hw.extra_reg.config >> 32) & 0xFFFFULL)
 
-static struct perf_amd_iommu __perf_iommu;
+#define PERF_AMD_IOMMU_NAME_SIZE	16
 
 struct perf_amd_iommu {
+	struct list_head list;
 	struct pmu pmu;
+	struct amd_iommu *iommu;
+	char name[PERF_AMD_IOMMU_NAME_SIZE];
 	u8 max_banks;
 	u8 max_counters;
 	u64 cntr_assign_mask;
 	raw_spinlock_t lock;
 };
 
+static LIST_HEAD(perf_amd_iommu_list);
+
 /*---------------------------------------------
  * sysfs format attributes
  *---------------------------------------------*/
@@ -202,8 +207,6 @@ static int clear_avail_iommu_bnk_cntr(struct perf_amd_iommu *perf_iommu,
 static int perf_iommu_event_init(struct perf_event *event)
 {
 	struct hw_perf_event *hwc = &event->hw;
-	struct perf_amd_iommu *perf_iommu;
-	u64 config, config1;
 
 	/* test the event attr type check for PMU enumeration */
 	if (event->attr.type != event->pmu->type)
@@ -225,28 +228,21 @@ static int perf_iommu_event_init(struct perf_event *event)
 	if (event->cpu < 0)
 		return -EINVAL;
 
-	perf_iommu = &__perf_iommu;
-
-	if (event->pmu != &perf_iommu->pmu)
-		return -ENOENT;
-
-	if (perf_iommu) {
-		config = event->attr.config;
-		config1 = event->attr.config1;
-	} else {
-		return -EINVAL;
-	}
-
 	/* update the hw_perf_event struct with the iommu config data */
-	hwc->config = config;
-	hwc->extra_reg.config = config1;
+	hwc->config           = event->attr.config;
+	hwc->extra_reg.config = event->attr.config1;
 
 	return 0;
 }
 
+static inline struct amd_iommu *perf_event_2_iommu(struct perf_event *ev)
+{
+	return (container_of(ev->pmu, struct perf_amd_iommu, pmu))->iommu;
+}
+
 static void perf_iommu_enable_event(struct perf_event *ev)
 {
-	struct amd_iommu *iommu = get_amd_iommu(0);
+	struct amd_iommu *iommu = perf_event_2_iommu(ev);
 	u8 csource = _GET_CSOURCE(ev);
 	u16 devid = _GET_DEVID(ev);
 	u8 bank = _GET_BANK(ev);
@@ -274,7 +270,7 @@ static void perf_iommu_enable_event(struct perf_event *ev)
 
 static void perf_iommu_disable_event(struct perf_event *event)
 {
-	struct amd_iommu *iommu = get_amd_iommu(0);
+	struct amd_iommu *iommu = perf_event_2_iommu(event);
 	u64 reg = 0ULL;
 
 	amd_iommu_pc_set_reg(iommu, _GET_BANK(event), _GET_CNTR(event),
@@ -284,7 +280,7 @@ static void perf_iommu_disable_event(struct perf_event *event)
 static void perf_iommu_start(struct perf_event *event, int flags)
 {
 	struct hw_perf_event *hwc = &event->hw;
-	struct amd_iommu *iommu = get_amd_iommu(0);
+	struct amd_iommu *iommu = perf_event_2_iommu(event);
 
 	if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
 		return;
@@ -307,7 +303,7 @@ static void perf_iommu_read(struct perf_event *event)
 {
 	u64 count, prev, delta;
 	struct hw_perf_event *hwc = &event->hw;
-	struct amd_iommu *iommu = get_amd_iommu(0);
+	struct amd_iommu *iommu = perf_event_2_iommu(event);
 
 	if (amd_iommu_pc_get_reg(iommu, _GET_BANK(event), _GET_CNTR(event),
 				 IOMMU_PC_COUNTER_REG, &count))
@@ -403,6 +399,13 @@ static __init int _init_events_attrs(void)
 
 static __init void amd_iommu_pc_exit(void)
 {
+	struct perf_amd_iommu *pi, *next;
+
+	list_for_each_entry_safe(pi, next, &perf_amd_iommu_list, list) {
+		list_del(&pi->list);
+		kfree(pi);
+	}
+
 	kfree(amd_iommu_events_group.attrs);
 }
 
@@ -414,46 +417,46 @@ static __init void amd_iommu_pc_exit(void)
 };
 
 static __init int
-_init_perf_amd_iommu(struct perf_amd_iommu *perf_iommu, char *name)
+init_one_perf_amd_iommu(struct perf_amd_iommu *perf_iommu, unsigned int idx)
 {
 	int ret;
 
 	raw_spin_lock_init(&perf_iommu->lock);
 
-	/* Init cpumask attributes to only core 0 */
-	cpumask_set_cpu(0, &iommu_cpumask);
-
-	perf_iommu->max_banks    = amd_iommu_pc_get_max_banks(0);
-	perf_iommu->max_counters = amd_iommu_pc_get_max_counters(0);
+	perf_iommu->iommu	 = get_amd_iommu(idx);
+	perf_iommu->max_banks    = amd_iommu_pc_get_max_banks(idx);
+	perf_iommu->max_counters = amd_iommu_pc_get_max_counters(idx);
 	if (!perf_iommu->max_banks || !perf_iommu->max_counters)
 		return -EINVAL;
 
+	snprintf(perf_iommu->name, PERF_AMD_IOMMU_NAME_SIZE, "amd_iommu_%u", idx);
+
+	perf_iommu->pmu.event_init  = perf_iommu_event_init;
+	perf_iommu->pmu.add         = perf_iommu_add;
+	perf_iommu->pmu.del         = perf_iommu_del;
+	perf_iommu->pmu.start       = perf_iommu_start;
+	perf_iommu->pmu.stop        = perf_iommu_stop;
+	perf_iommu->pmu.read        = perf_iommu_read;
+	perf_iommu->pmu.task_ctx_nr = perf_invalid_context;
 	perf_iommu->pmu.attr_groups = amd_iommu_attr_groups;
-	ret = perf_pmu_register(&perf_iommu->pmu, name, -1);
+
+	ret = perf_pmu_register(&perf_iommu->pmu, perf_iommu->name, -1);
 	if (ret)
 		pr_err("Error initializing AMD IOMMU perf counters.\n");
 	else
-		pr_info("perf: amd_iommu: Detected. (%d banks, %d counters/bank)\n",
-			amd_iommu_pc_get_max_banks(0),
-			amd_iommu_pc_get_max_counters(0));
+	pr_info("Detected AMD IOMMU #%d (%d banks, %d counters/bank)\n",
+		idx, amd_iommu_pc_get_max_banks(idx),
+		amd_iommu_pc_get_max_counters(idx));
 	return ret;
 }
 
-static struct perf_amd_iommu __perf_iommu = {
-	.pmu = {
-		.task_ctx_nr    = perf_invalid_context,
-		.event_init	= perf_iommu_event_init,
-		.add		= perf_iommu_add,
-		.del		= perf_iommu_del,
-		.start		= perf_iommu_start,
-		.stop		= perf_iommu_stop,
-		.read		= perf_iommu_read,
-	},
-};
-
 static __init int amd_iommu_pc_init(void)
 {
 	int ret;
+	unsigned int i;
+
+	/* Init cpumask attributes to only core 0 */
+	cpumask_set_cpu(0, &iommu_cpumask);
 
 	/* Make sure the IOMMU PC resource is available */
 	if (!amd_iommu_pc_supported())
@@ -463,7 +466,24 @@ static __init int amd_iommu_pc_init(void)
 	if (ret)
 		return ret;
 
-	ret = _init_perf_amd_iommu(&__perf_iommu, "amd_iommu");
+	for (i = 0 ; i < amd_iommu_get_num_iommus(); i++) {
+		struct perf_amd_iommu *pi;
+
+		pi = kzalloc(sizeof(struct perf_amd_iommu), GFP_KERNEL);
+		if (!pi) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		ret = init_one_perf_amd_iommu(pi, i);
+		if (ret) {
+			kfree(pi);
+			break;
+		}
+
+		list_add_tail(&pi->list, &perf_amd_iommu_list);
+	}
+
 	if (ret)
 		amd_iommu_pc_exit();
 
-- 
1.8.3.1