On 2015/11/3 4:54, Christopher Covington wrote:
> Hi Shannon,
>
> On 10/30/2015 02:21 AM, Shannon Zhao wrote:
>> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>>
>> Since the reset value of PMXEVTYPER is UNKNOWN, use reset_unknown or
>> reset_unknown_cp15 for its reset handler. Add access handler which
>> emulates writing and reading PMXEVTYPER register. When writing to
>> PMXEVTYPER, call kvm_pmu_set_counter_event_type to create a perf_event
>> for the selected event type.
>>
>> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>> ---
>> arch/arm64/kvm/sys_regs.c | 26 ++++++++++++++++++++++++--
>> 1 file changed, 24 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> index cb82b15..4e606ea 100644
>> --- a/arch/arm64/kvm/sys_regs.c
>> +++ b/arch/arm64/kvm/sys_regs.c
>> @@ -491,6 +491,17 @@ static bool access_pmu_regs(struct kvm_vcpu *vcpu,
>>
>> if (p->is_write) {
>> switch (r->reg) {
>> + case PMXEVTYPER_EL0: {
>> + val = vcpu_sys_reg(vcpu, PMSELR_EL0);
>> + kvm_pmu_set_counter_event_type(vcpu,
>> + *vcpu_reg(vcpu, p->Rt),
>> + val);
>> + vcpu_sys_reg(vcpu, PMXEVTYPER_EL0) =
>> + *vcpu_reg(vcpu, p->Rt);
>
> Why does PMXEVTYPER get set directly? It seems like it could have an accessor
> that redirected to PMEVTYPER<n>.
>
Yeah, that's what this patch does. It gets the counter index from
PMSELR_EL0 register, then set the event type, create perf_event, store
event type to PMEVTYPER<n>, etc.
>> + vcpu_sys_reg(vcpu, PMEVTYPER0_EL0 + val) =
>> + *vcpu_reg(vcpu, p->Rt);
>
> I tried to look around briefly but couldn't find counter number range checking
> in the PMSELR handler or here. Should there be some here and in PMXEVCNTR?
>
Ok, will fix this. Thanks.
--
Shannon
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