On 27/01/2025 22:20, Colton Lewis wrote:
If the PMU is partitioned, keep the driver out of the guest counter
partition and only use the host counter partition. Partitioning is
defined by the MDCR_EL2.HPMN register field and saved in
cpu_pmu->hpmn. The range 0..HPMN-1 is accessible by EL1 and EL0 while
HPMN..PMCR.N is reserved for EL2.
Define some macros that take HPMN as an argument and construct
mutually exclusive bitmaps for testing which partition a particular
counter is in. Note that despite their different position in the
bitmap, the cycle and instruction counters are always in the guest
partition.
Signed-off-by: Colton Lewis <coltonlewis@xxxxxxxxxx>
---
drivers/perf/arm_pmuv3.c | 72 +++++++++++++++++++++++++++++-----
include/linux/perf/arm_pmuv3.h | 8 ++++
2 files changed, 70 insertions(+), 10 deletions(-)
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index 55f9ae560715..c61845fad9d9 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -754,15 +754,19 @@ static void armv8pmu_disable_event_irq(struct perf_event *event)
armv8pmu_disable_intens(BIT(event->hw.idx));
}
-static u64 armv8pmu_getreset_flags(void)
+static u64 armv8pmu_getreset_flags(struct arm_pmu *cpu_pmu)
{
u64 value;
/* Read */
value = read_pmovsclr();
+ if (cpu_pmu->partitioned)
+ value &= ARMV8_PMU_HOST_CNT_PART(cpu_pmu->hpmn);
+ else
+ value &= ARMV8_PMU_OVERFLOWED_MASK;
+
/* Write to clear flags */
- value &= ARMV8_PMU_OVERFLOWED_MASK;
write_pmovsclr(value);
return value;
@@ -789,6 +793,18 @@ static void armv8pmu_disable_user_access(void)
update_pmuserenr(0);
}
+static bool armv8pmu_is_guest_part(struct arm_pmu *cpu_pmu, u8 idx)
+{
+ return cpu_pmu->partitioned &&
+ (BIT(idx) & ARMV8_PMU_GUEST_CNT_PART(cpu_pmu->hpmn));
+}
+
+static bool armv8pmu_is_host_part(struct arm_pmu *cpu_pmu, u8 idx)
+{
+ return !cpu_pmu->partitioned ||
+ (BIT(idx) & ARMV8_PMU_HOST_CNT_PART(cpu_pmu->hpmn));
+}
+
static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
{
int i;
@@ -797,6 +813,8 @@ static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
if (is_pmuv3p9(cpu_pmu->pmuver)) {
u64 mask = 0;
for_each_set_bit(i, cpuc->used_mask, ARMPMU_MAX_HWEVENTS) {
+ if (armv8pmu_is_guest_part(cpu_pmu, i))
+ continue;
if (armv8pmu_event_has_user_read(cpuc->events[i]))
mask |= BIT(i);
}
@@ -805,6 +823,8 @@ static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
/* Clear any unused counters to avoid leaking their contents */
for_each_andnot_bit(i, cpu_pmu->cntr_mask, cpuc->used_mask,
ARMPMU_MAX_HWEVENTS) {
+ if (armv8pmu_is_guest_part(cpu_pmu, i))
+ continue;
if (i == ARMV8_PMU_CYCLE_IDX)
write_pmccntr(0);
else if (i == ARMV8_PMU_INSTR_IDX)
@@ -850,7 +870,10 @@ static void armv8pmu_start(struct arm_pmu *cpu_pmu)
armv8pmu_disable_user_access();
/* Enable all counters */
- armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E);
+ if (cpu_pmu->partitioned)
+ armv8pmu_mdcr_write(armv8pmu_mdcr_read() | ARMV8_PMU_MDCR_HPME);
+ else
+ armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E);
kvm_vcpu_pmu_resync_el0();
}
@@ -858,7 +881,10 @@ static void armv8pmu_start(struct arm_pmu *cpu_pmu)
static void armv8pmu_stop(struct arm_pmu *cpu_pmu)
{
/* Disable all counters */
- armv8pmu_pmcr_write(armv8pmu_pmcr_read() & ~ARMV8_PMU_PMCR_E);
+ if (cpu_pmu->partitioned)
+ armv8pmu_mdcr_write(armv8pmu_pmcr_read() & ~ARMV8_PMU_MDCR_HPME);
typo: s/armv8pmu_pmcr_read/armv8pmu_mdcr_read
Suzuki
+ else
+ armv8pmu_pmcr_write(armv8pmu_pmcr_read() & ~ARMV8_PMU_PMCR_E);
}
static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu)
@@ -872,7 +898,7 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu)
/*
* Get and reset the IRQ flags
*/
- pmovsr = armv8pmu_getreset_flags();
+ pmovsr = armv8pmu_getreset_flags(cpu_pmu);
/*
* Did an overflow occur?
@@ -930,6 +956,8 @@ static int armv8pmu_get_single_idx(struct pmu_hw_events *cpuc,
int idx;
for_each_set_bit(idx, cpu_pmu->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS) {
+ if (armv8pmu_is_guest_part(cpu_pmu, idx))
+ continue;
if (!test_and_set_bit(idx, cpuc->used_mask))
return idx;
}
@@ -946,6 +974,8 @@ static int armv8pmu_get_chain_idx(struct pmu_hw_events *cpuc,
* the lower idx must be even.
*/
for_each_set_bit(idx, cpu_pmu->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS) {
+ if (armv8pmu_is_guest_part(cpu_pmu, idx))
+ continue;
if (!(idx & 0x1))
continue;
if (!test_and_set_bit(idx, cpuc->used_mask)) {
@@ -968,6 +998,7 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc,
/* Always prefer to place a cycle counter into the cycle counter. */
if ((evtype == ARMV8_PMUV3_PERFCTR_CPU_CYCLES) &&
+ !cpu_pmu->partitioned &&
!armv8pmu_event_get_threshold(&event->attr)) {
if (!test_and_set_bit(ARMV8_PMU_CYCLE_IDX, cpuc->used_mask))
return ARMV8_PMU_CYCLE_IDX;
@@ -983,6 +1014,7 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc,
* may not know how to handle it.
*/
if ((evtype == ARMV8_PMUV3_PERFCTR_INST_RETIRED) &&
+ !cpu_pmu->partitioned &&
!armv8pmu_event_get_threshold(&event->attr) &&
test_bit(ARMV8_PMU_INSTR_IDX, cpu_pmu->cntr_mask) &&
!armv8pmu_event_want_user_access(event)) {
@@ -994,7 +1026,7 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc,
* Otherwise use events counters
*/
if (armv8pmu_event_is_chained(event))
- return armv8pmu_get_chain_idx(cpuc, cpu_pmu);
+ return armv8pmu_get_chain_idx(cpuc, cpu_pmu);
else
return armv8pmu_get_single_idx(cpuc, cpu_pmu);
}
@@ -1086,6 +1118,15 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
return 0;
}
+static void armv8pmu_reset_host_counters(struct arm_pmu *cpu_pmu)
+{
+ int idx;
+
+ for_each_set_bit(idx, cpu_pmu->cntr_mask, ARMV8_PMU_MAX_GENERAL_COUNTERS)
+ if (armv8pmu_is_host_part(cpu_pmu, idx))
+ armv8pmu_write_evcntr(idx, 0);
+}
+
static void armv8pmu_reset(void *info)
{
struct arm_pmu *cpu_pmu = (struct arm_pmu *)info;
@@ -1093,8 +1134,10 @@ static void armv8pmu_reset(void *info)
bitmap_to_arr64(&mask, cpu_pmu->cntr_mask, ARMPMU_MAX_HWEVENTS);
- if (cpu_pmu->partitioned)
+ if (cpu_pmu->partitioned) {
armv8pmu_partition(cpu_pmu->hpmn);
+ mask &= ARMV8_PMU_HOST_CNT_PART(cpu_pmu->hpmn);
+ }
/* The counter and interrupt enable registers are unknown at reset. */
armv8pmu_disable_counter(mask);
@@ -1103,11 +1146,20 @@ static void armv8pmu_reset(void *info)
/* Clear the counters we flip at guest entry/exit */
kvm_clr_pmu_events(mask);
+
+ pmcr = ARMV8_PMU_PMCR_LC;
+
/*
- * Initialize & Reset PMNC. Request overflow interrupt for
- * 64 bit cycle counter but cheat in armv8pmu_write_counter().
+ * Initialize & Reset PMNC. Request overflow interrupt for 64
+ * bit cycle counter but cheat in armv8pmu_write_counter().
+ *
+ * When partitioned, there is no single bit to reset only the
+ * host counters. so reset them individually.
*/
- pmcr = ARMV8_PMU_PMCR_P | ARMV8_PMU_PMCR_C | ARMV8_PMU_PMCR_LC;
+ if (cpu_pmu->partitioned)
+ armv8pmu_reset_host_counters(cpu_pmu);
+ else
+ pmcr = ARMV8_PMU_PMCR_P | ARMV8_PMU_PMCR_C;
/* Enable long event counter support where available */
if (armv8pmu_has_long_event(cpu_pmu))
diff --git a/include/linux/perf/arm_pmuv3.h b/include/linux/perf/arm_pmuv3.h
index 115ee39f693a..5f8b143794ce 100644
--- a/include/linux/perf/arm_pmuv3.h
+++ b/include/linux/perf/arm_pmuv3.h
@@ -247,6 +247,14 @@
#define ARMV8_PMU_OVSR_F ARMV8_PMU_CNT_MASK_F
/* Mask for writable bits is both P and C fields */
#define ARMV8_PMU_OVERFLOWED_MASK ARMV8_PMU_CNT_MASK_ALL
+
+/* Masks for guest and host counter partitions */
+#define ARMV8_PMU_HPMN_CNT_MASK(N) GENMASK((N) - 1, 0)
+#define ARMV8_PMU_GUEST_CNT_PART(N) (ARMV8_PMU_HPMN_CNT_MASK(N) | \
+ ARMV8_PMU_CNT_MASK_C | \
+ ARMV8_PMU_CNT_MASK_F)
+#define ARMV8_PMU_HOST_CNT_PART(N) (ARMV8_PMU_CNT_MASK_ALL & \
+ ~ARMV8_PMU_GUEST_CNT_PART(N))
/*
* PMXEVTYPER: Event selection reg
*/
