Hi Wei,
On 2016-11-02 14:55, Wei Huang wrote:
KVM calls kvm_pmu_set_counter_event_type() when PMCCFILTR is
configured.
But this function can't deals with PMCCFILTR correctly because the
evtCount
bit of PMCCFILTR, which is reserved 0, conflits with the SW_INCR event
type of other PMXEVTYPER<n> registers. To fix it, when eventsel == 0,
KVM
shouldn't return immediately, but instead it needs to check further if
select_idx is ARMV8_PMU_CYCLE_IDX.
Another issue is that KVM shouldn't copy the eventsel bits of
PMCCFILTER
directly to attr.config. Istead it shoudl convert the request to
perf_event of type 0x11 (i.e. the "cpu cycle" event type).
Signed-off-by: Wei Huang <wei@xxxxxxxxxx>
---
virt/kvm/arm/pmu.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/virt/kvm/arm/pmu.c b/virt/kvm/arm/pmu.c
index 6e9c40e..13cc812 100644
--- a/virt/kvm/arm/pmu.c
+++ b/virt/kvm/arm/pmu.c
@@ -379,7 +379,8 @@ void kvm_pmu_set_counter_event_type(struct
kvm_vcpu *vcpu, u64 data,
eventsel = data & ARMV8_PMU_EVTYPE_EVENT;
/* Software increment event does't need to be backed by a perf event
*/
- if (eventsel == ARMV8_PMU_EVTYPE_EVENT_SW_INCR)
+ if (eventsel == ARMV8_PMU_EVTYPE_EVENT_SW_INCR &&
+ select_idx != ARMV8_PMU_CYCLE_IDX)
return;
memset(&attr, 0, sizeof(struct perf_event_attr));
@@ -391,7 +392,7 @@ void kvm_pmu_set_counter_event_type(struct
kvm_vcpu *vcpu, u64 data,
attr.exclude_kernel = data & ARMV8_PMU_EXCLUDE_EL1 ? 1 : 0;
attr.exclude_hv = 1; /* Don't count EL2 events */
attr.exclude_host = 1; /* Don't count host events */
- attr.config = eventsel;
+ attr.config = (select_idx == ARMV8_PMU_CYCLE_IDX) ? 0x011 : eventsel;
Nit: Is there some way you could use ARMV8_PMUV3_PERFCTR_CPU_CYCLES
currently
defined in arch/arm64/kernel/perf_event.c?
Thanks,
Cov
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