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SubjectRe: [RFC PATCH] perf/kvm: Guest Symbol Resolution for powerpc
On 6/15/15 8:50 PM, Hemant Kumar wrote:
> +/*
> + * Get the instruction pointer from the tracepoint data
> + */
> +u64 arch__get_ip(struct perf_evsel *evsel, struct perf_sample *data)
> +{
> + u64 tp_ip = data->ip;
> + int trap;
> +
> + if (!strcmp(KVMPPC_EXIT, evsel->name)) {
> + trap = raw_field_value(evsel->tp_format, "trap", data->raw_data);
> +
> + if (trap == HV_DECREMENTER)
> + tp_ip = raw_field_value(evsel->tp_format, "pc",
> + data->raw_data);
> + }
> + return tp_ip;
> +}

You can tie a handler to an event; see builtin-trace.c for example
(evsel->handler = handler). Then have the sample handler call it (e.g,
see trace__process_sample). Then you don't have to check event names on
each pass like this and just do event based processing.

> +
> +/*
> + * Get the HV and PR bits and accordingly, determine the cpumode
> + */
> +u8 arch__get_cpumode(union perf_event *event, struct perf_evsel *evsel,
> + struct perf_sample *data)
> +{
> + unsigned long hv, pr, msr;
> + u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
> +
> + if (strcmp(KVMPPC_EXIT, evsel->name))
> + goto ret;
> +
> + if (data->raw_data)
> + msr = raw_field_value(evsel->tp_format, "msr", data->raw_data);
> + else
> + goto ret;
> +
> + hv = msr & ((long unsigned)1 << (PPC_MAX - HV_BIT));
> + pr = msr & ((long unsigned)1 << (PPC_MAX - PR_BIT));
> +
> + if (!hv && pr)
> + cpumode = PERF_RECORD_MISC_GUEST_USER;
> + else
> + cpumode = PERF_RECORD_MISC_GUEST_KERNEL;
> +ret:
> + return cpumode;
> +}

Why isn't that set properly kernel side when the sample is generated?

David


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