On 11/03/2014 12:36 PM, Radim Krčmář wrote:
> 2014-10-31 12:05-0400, Wei Huang:
>> This patch converts existing pmu.c into Intel specific code and hooks
>> up with the PMU interface using the following steps:
>>
>> - Convert pmu.c to pmu_intel.c; All public PMU functions are renamed
>> and hooked up with the newly defined intel_pmu_ops.
>> - Create a corresponding pmu_amd.c file with empty functions for AMD
>> arch.
>> - The PMU function pointer, kvm_pmu_ops, is initialized by calling
>> kvm_x86_ops->get_pmu_ops().
>> - To reduce the code size, Intel and AMD modules are now generated
>> from their corrponding arch and PMU files; In the meanwhile, due
>> to this arrangement several, functions are exposed as public ones
>> to allow calling from PMU code.
>
> (Patch would have been easier to review as two patches, where the first
> one just renames pmu to pmu_intel and the second one does the split.)
Will do in next spin.
>
>> Signed-off-by: Wei Huang <w...@redhat.com>
>> ---
>
> ---
> The rest is an idea for consideration ...
> Please consider everything from now to be in parentheses
> = ignore you are not enjoying shuffling code around.
>
>> +
>> +static unsigned find_arch_event(struct kvm_pmu *pmu, u8 event_select,
>> + u8 unit_mask)
>
> The prototype could be exteded with
> struct kvm_event_hw_type_mapping, size_t nr_events
> and reused for AMD as well.
>
>> +{
>> + int i;
>> +
>> + for (i = 0; i < ARRAY_SIZE(intel_arch_events); i++)
>> + if (intel_arch_events[i].eventsel == event_select
>> + && intel_arch_events[i].unit_mask == unit_mask
>> + && (pmu->available_event_types & (1 << i)))
>
> pmu->available_event_types would be -1 on AMD.
>
>> + break;
>> +
>> + if (i == ARRAY_SIZE(intel_arch_events))
>> + return PERF_COUNT_HW_MAX;
>> +
>> + return intel_arch_events[i].event_type;
>> +}
>
>> +static void reprogram_counter(struct kvm_pmc *pmc, u32 type,
>> + unsigned config, bool exclude_user, bool exclude_kernel,
>> + bool intr, bool in_tx, bool in_tx_cp)
>
> This function could drop 'bool in_tx' and 'bool in_tx_cp', because it
> already accepts config, so these flags can already be included there.
> It has only one caller that uses them anyway.
>
>> +{
>> + struct perf_event *event;
>> + struct perf_event_attr attr = {
>> + .type = type,
>> + .size = sizeof(attr),
>> + .pinned = true,
>> + .exclude_idle = true,
>> + .exclude_host = 1,
>> + .exclude_user = exclude_user,
>> + .exclude_kernel = exclude_kernel,
>> + .config = config,
>> + };
>> + if (in_tx)
>> + attr.config |= HSW_IN_TX;
>> + if (in_tx_cp)
>> + attr.config |= HSW_IN_TX_CHECKPOINTED;
>
> And after dropping this, it is identical to AMD.
Thanks. I will consolidate the ideas above into next spin.
>
>> +
>> + attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc);
>> +
>> + event = perf_event_create_kernel_counter(&attr, -1, current,
>> + intr ? kvm_perf_overflow_intr :
>> + kvm_perf_overflow, pmc);
>> + if (IS_ERR(event)) {
>> + printk_once("kvm: pmu event creation failed %ld\n",
>> + PTR_ERR(event));
>> + return;
>> + }
>> +
>> + pmc->perf_event = event;
>> + clear_bit(pmc->idx, (unsigned long*)&pmc->vcpu->arch.pmu.reprogram_pmi);
>> +}
>> +
>> +static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
>> +{
>
> Because the two functions that this one uses have been merged, we could
> propagate the changes and reuse this one with AMD as well.
>
>> + unsigned config, type = PERF_TYPE_RAW;
>> + u8 event_select, unit_mask;
>> +
>> + if (eventsel & ARCH_PERFMON_EVENTSEL_PIN_CONTROL)
>> + printk_once("kvm pmu: pin control bit is ignored\n");
>> +
>> + pmc->eventsel = eventsel;
>> +
>> + stop_counter(pmc);
>> +
>> + if (!(eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) || !pmc_enabled(pmc))
>> + return;
>> +
>> + event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
>> + unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
>> +
>> + if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
>> + ARCH_PERFMON_EVENTSEL_INV |
>> + ARCH_PERFMON_EVENTSEL_CMASK |
>> + HSW_IN_TX |
>> + HSW_IN_TX_CHECKPOINTED))) {
>> + config = find_arch_event(&pmc->vcpu->arch.pmu, event_select,
>> + unit_mask);
>> + if (config != PERF_COUNT_HW_MAX)
>> + type = PERF_TYPE_HARDWARE;
>> + }
>> +
>> + if (type == PERF_TYPE_RAW)
>> + config = eventsel & X86_RAW_EVENT_MASK;
>> +
>> + reprogram_counter(pmc, type, config,
>> + !(eventsel & ARCH_PERFMON_EVENTSEL_USR),
>> + !(eventsel & ARCH_PERFMON_EVENTSEL_OS),
>> + eventsel & ARCH_PERFMON_EVENTSEL_INT,
>> + (eventsel & HSW_IN_TX),
>> + (eventsel & HSW_IN_TX_CHECKPOINTED));
>> +}
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