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

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 <pet...@infradead.org>
Cc: Borislav Petkov <b...@alien8.de>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
---
 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

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