On 05/02/2019 14:33, Julien Thierry wrote:
Hi Andrew,
On 04/02/2019 16:53, Andrew Murray wrote:
Emulate chained PMU counters by creating a single 64 bit event counter
for a pair of chained KVM counters.
Signed-off-by: Andrew Murray <[email protected]>
---
include/kvm/arm_pmu.h | 1 +
virt/kvm/arm/pmu.c | 321 +++++++++++++++++++++++++++++++++++++++++---------
2 files changed, 269 insertions(+), 53 deletions(-)
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index b73f31b..8e691ee 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -29,6 +29,7 @@ struct kvm_pmc {
u8 idx; /* index into the pmu->pmc array */
struct perf_event *perf_event;
u64 bitmask;
+ u64 overflow_count;
};
struct kvm_pmu {
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index a64aeb2..9318130 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -24,9 +24,25 @@
#include <kvm/arm_pmu.h>
#include <kvm/arm_vgic.h>
+#define ARMV8_PMUV3_PERFCTR_CHAIN 0x1E
I find it a bit awkward to have this redefined here.
Maybe we could define a helper in kvm_host.h:
bool kvm_pmu_typer_is_chain(u64 typer);
That would always return false for arm32?
We don't support ARMv7 host, so that doesn't matter. But
it is a good idea to wrap it in a function here.
kvm_vcpu_kick(vcpu);
@@ -440,6 +632,10 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu
*vcpu, u64 select_idx)
select_idx != ARMV8_PMU_CYCLE_IDX)
return;
+ /* Handled by even event */
+ if (eventsel == ARMV8_PMUV3_PERFCTR_CHAIN)
+ return;
+
memset(&attr, 0, sizeof(struct perf_event_attr));
attr.type = PERF_TYPE_RAW;
attr.size = sizeof(attr);
@@ -452,6 +648,9 @@ static void kvm_pmu_create_perf_event(struct kvm_vcpu
*vcpu, u64 select_idx)
attr.config = (select_idx == ARMV8_PMU_CYCLE_IDX) ?
ARMV8_PMUV3_PERFCTR_CPU_CYCLES : eventsel;
+ if (kvm_pmu_event_is_chained(vcpu, select_idx))
+ attr.config1 |= 0x1;
I'm not very familiar with the usage of perf attributes configs, but is
there any chance we could name this flag? Even if only for the local
file? Something like PERF_ATTR_CFG1_KVM_PMU_CHAINED (unless there is an
existing naming convention for event attributes).
There is ARPMU_EVT_64BIT in "linux/perf/arm_pmu.h". But in general we don't
specify where the Bit goes in (i.e, CFG1 etc).
Cheers
Suzuki
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