On Fri, May 17, 2013 at 02:43:32PM -0500, Suthikulpanit, Suravee wrote:
> diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
> index b0684e4..fcbd3b8 100644
> --- a/arch/x86/kernel/cpu/Makefile
> +++ b/arch/x86/kernel/cpu/Makefile
> @@ -30,7 +30,7 @@ obj-$(CONFIG_CPU_SUP_UMC_32) += umc.o
> obj-$(CONFIG_PERF_EVENTS) += perf_event.o
>
> ifdef CONFIG_PERF_EVENTS
> -obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd.o
> perf_event_amd_uncore.o
> +obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd.o
> perf_event_amd_uncore.o perf_event_amd_iommu.o
This should also depend on CONFIG_AMD_IOMMU. If no IOMMU driver is
compiled in it doesn't make sense to have that PMU.
> +static int perf_iommu_event_init(struct perf_event *event)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + struct perf_amd_iommu *perf_iommu;
> + u64 config, config1;
> +
> + /* test the event attr type check for PMU enumeration */
> + if (event->attr.type != event->pmu->type)
> + return -ENOENT;
> +
> + /*
> + * IOMMU counters are shared across all cores.
> + * Therefore, it does not support per-process mode.
> + * Also, it does not support event sampling mode.
> + */
> + if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
> + return -EINVAL;
> +
> + /* IOMMU counters do not have usr/os/guest/host bits */
> + if (event->attr.exclude_user || event->attr.exclude_kernel ||
> + event->attr.exclude_host || event->attr.exclude_guest)
> + return -EINVAL;
> +
> + if (event->cpu < 0)
> + return -EINVAL;
> +
> + perf_iommu = &__perf_iommu;
> +
> + if (event->pmu != &perf_iommu->pmu)
> + return -ENOENT;
> +
> + if (perf_iommu) {
> + config = event->attr.config;
> + config1 = event->attr.config1;
> + } else {
> + return -EINVAL;
> + }
> +
> + /* integrate with iommu base devid (0000), assume one iommu */
> + perf_iommu->max_banks =
> + amd_iommu_pc_get_max_banks(IOMMU_BASE_DEVID);
> + perf_iommu->max_counters =
> + amd_iommu_pc_get_max_counters(IOMMU_BASE_DEVID);
> +
> + /* update the hw_perf_event struct with the iommu config data */
> + hwc->config = config;
> + hwc->extra_reg.config = config1;
> +
> + return 0;
> +}
That implementation is very basic. Any reason for not using the event
reporting mechanism of the IOMMU? You could implement a nice perf
iommutop or something to see which devices do the most transactions or
something like that.
Joerg
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