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Subject[PATCH v3] perf, x86: Fix multi-segment problem of perf_event_intel_uncore
Date
In multi-segment system, uncore devices may belong to buses whose segment
number is other than 0.

....
0000:ff:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03)
...
0001:7f:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03)
...
0001:bf:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03)
...
0001:ff:10.5 System peripheral: Intel Corporation Xeon E5 v3/Core i7 Scratchpad & Semaphore Registers (rev 03
...

In that case relation of bus number and physical id may be broken
because "uncore_pcibus_to_physid" doesn't take account of PCI segment.
For example, bus 0000:ff and 0001:ff uses the same entry of
"uncore_pcibus_to_physid" array.

This patch fixes ths problem by introducing segment-aware pci2phy_map instead.

v2 -> v3:
- fix up according to Peter's comment
- introduce __find_pci2phy_map() to avert repetition

Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
---
arch/x86/kernel/cpu/perf_event_intel_uncore.c | 45 ++++++++++++++++++++--
arch/x86/kernel/cpu/perf_event_intel_uncore.h | 12 +++++-
arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c | 13 ++++++-
.../x86/kernel/cpu/perf_event_intel_uncore_snbep.c | 31 +++++++++++----
4 files changed, 87 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index 560e525..1ddac35 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -7,7 +7,8 @@ struct intel_uncore_type **uncore_pci_uncores = empty_uncore;
static bool pcidrv_registered;
struct pci_driver *uncore_pci_driver;
/* pci bus to socket mapping */
-int uncore_pcibus_to_physid[256] = { [0 ... 255] = -1, };
+DEFINE_RAW_SPINLOCK(pci2phy_map_lock);
+struct list_head pci2phy_map_head = LIST_HEAD_INIT(pci2phy_map_head);
struct pci_dev *uncore_extra_pci_dev[UNCORE_SOCKET_MAX][UNCORE_EXTRA_PCI_DEV_MAX];

static DEFINE_RAW_SPINLOCK(uncore_box_lock);
@@ -20,6 +21,43 @@ static struct event_constraint uncore_constraint_fixed =
struct event_constraint uncore_constraint_empty =
EVENT_CONSTRAINT(0, 0, 0);

+int uncore_pcibus_to_physid(struct pci_bus *bus)
+{
+ struct pci2phy_map *map;
+ int phys_id = -1;
+
+ raw_spin_lock(&pci2phy_map_lock);
+ list_for_each_entry(map, &pci2phy_map_head, list) {
+ if (map->segment == pci_domain_nr(bus)) {
+ phys_id = map->pbus_to_physid[bus->number];
+ break;
+ }
+ }
+ raw_spin_unlock(&pci2phy_map_lock);
+
+ return phys_id;
+}
+
+struct pci2phy_map *__find_pci2phy_map(int segment)
+{
+ struct pci2phy_map *map;
+
+ lockdep_assert_held(&pci2phy_map_lock);
+
+ list_for_each_entry(map, &pci2phy_map_head, list) {
+ if (map->segment == segment)
+ return map;
+ }
+
+ map = kmalloc(sizeof(struct pci2phy_map), GFP_ATOMIC);
+ if (map) {
+ map->segment = segment;
+ list_add_tail(&map->list, &pci2phy_map_head);
+ }
+
+ return map;
+}
+
ssize_t uncore_event_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
@@ -809,7 +847,7 @@ static int uncore_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id
int phys_id;
bool first_box = false;

- phys_id = uncore_pcibus_to_physid[pdev->bus->number];
+ phys_id = uncore_pcibus_to_physid(pdev->bus);
if (phys_id < 0)
return -ENODEV;

@@ -856,9 +894,10 @@ static void uncore_pci_remove(struct pci_dev *pdev)
{
struct intel_uncore_box *box = pci_get_drvdata(pdev);
struct intel_uncore_pmu *pmu;
- int i, cpu, phys_id = uncore_pcibus_to_physid[pdev->bus->number];
+ int i, cpu, phys_id;
bool last_box = false;

+ phys_id = uncore_pcibus_to_physid(pdev->bus);
box = pci_get_drvdata(pdev);
if (!box) {
for (i = 0; i < UNCORE_EXTRA_PCI_DEV_MAX; i++) {
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.h b/arch/x86/kernel/cpu/perf_event_intel_uncore.h
index 72c54c2..2f0a4a9 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.h
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.h
@@ -117,6 +117,15 @@ struct uncore_event_desc {
const char *config;
};

+struct pci2phy_map {
+ struct list_head list;
+ int segment;
+ int pbus_to_physid[256];
+};
+
+int uncore_pcibus_to_physid(struct pci_bus *bus);
+struct pci2phy_map *__find_pci2phy_map(int segment);
+
ssize_t uncore_event_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf);

@@ -317,7 +326,8 @@ u64 uncore_shared_reg_config(struct intel_uncore_box *box, int idx);
extern struct intel_uncore_type **uncore_msr_uncores;
extern struct intel_uncore_type **uncore_pci_uncores;
extern struct pci_driver *uncore_pci_driver;
-extern int uncore_pcibus_to_physid[256];
+extern raw_spinlock_t pci2phy_map_lock;
+extern struct list_head pci2phy_map_head;
extern struct pci_dev *uncore_extra_pci_dev[UNCORE_SOCKET_MAX][UNCORE_EXTRA_PCI_DEV_MAX];
extern struct event_constraint uncore_constraint_empty;

diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c b/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c
index f78574b..17582bf 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c
@@ -420,15 +420,24 @@ static void snb_uncore_imc_event_del(struct perf_event *event, int flags)
static int snb_pci2phy_map_init(int devid)
{
struct pci_dev *dev = NULL;
- int bus;
+ struct pci2phy_map *map;
+ int bus, segment;

dev = pci_get_device(PCI_VENDOR_ID_INTEL, devid, dev);
if (!dev)
return -ENOTTY;

bus = dev->bus->number;
+ segment = pci_domain_nr(dev->bus);

- uncore_pcibus_to_physid[bus] = 0;
+ raw_spin_lock(&pci2phy_map_lock);
+ map = __find_pci2phy_map(segment);
+ if (!map) {
+ raw_spin_unlock(&pci2phy_map_lock);
+ return -ENOMEM;
+ }
+ map->pbus_to_physid[bus] = 0;
+ raw_spin_unlock(&pci2phy_map_lock);

pci_dev_put(dev);

diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c b/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c
index 694510a8..e1a4259 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore_snbep.c
@@ -1087,7 +1087,8 @@ static struct pci_driver snbep_uncore_pci_driver = {
static int snbep_pci2phy_map_init(int devid)
{
struct pci_dev *ubox_dev = NULL;
- int i, bus, nodeid;
+ int i, bus, nodeid, segment;
+ struct pci2phy_map *map;
int err = 0;
u32 config = 0;

@@ -1106,16 +1107,26 @@ static int snbep_pci2phy_map_init(int devid)
err = pci_read_config_dword(ubox_dev, 0x54, &config);
if (err)
break;
+
+ segment = pci_domain_nr(ubox_dev->bus);
+ raw_spin_lock(&pci2phy_map_lock);
+ map = __find_pci2phy_map(segment);
+ if (!map) {
+ err = -ENOMEM;
+ break;
+ }
+
/*
* every three bits in the Node ID mapping register maps
* to a particular node.
*/
for (i = 0; i < 8; i++) {
if (nodeid == ((config >> (3 * i)) & 0x7)) {
- uncore_pcibus_to_physid[bus] = i;
+ map->pbus_to_physid[bus] = i;
break;
}
}
+ raw_spin_unlock(&pci2phy_map_lock);
}

if (!err) {
@@ -1123,13 +1134,17 @@ static int snbep_pci2phy_map_init(int devid)
* For PCI bus with no UBOX device, find the next bus
* that has UBOX device and use its mapping.
*/
- i = -1;
- for (bus = 255; bus >= 0; bus--) {
- if (uncore_pcibus_to_physid[bus] >= 0)
- i = uncore_pcibus_to_physid[bus];
- else
- uncore_pcibus_to_physid[bus] = i;
+ raw_spin_lock(&pci2phy_map_lock);
+ list_for_each_entry(map, &pci2phy_map_head, list) {
+ i = -1;
+ for (bus = 255; bus >= 0; bus--) {
+ if (map->pbus_to_physid[bus] >= 0)
+ i = map->pbus_to_physid[bus];
+ else
+ map->pbus_to_physid[bus] = i;
+ }
}
+ raw_spin_unlock(&pci2phy_map_lock);
}

pci_dev_put(ubox_dev);
--
1.8.3.1


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