On Mon, Jan 16, 2012 at 9:32 AM, Xiao Guangrong
<xiaoguangrong@xxxxxxxxxxxxxxxxxx> wrote:
> +DESCRIPTION
> +-----------
> +You can analyze some crucial events and statistics with this
> +'perf kvm-events' command.
This line is very general and does not explain which events/statistics
can be collected or how you can use that information. I suggest
making this description more specific. Explain that this subcommand
observers kvm.ko tracepoints and annotates/decodes them with
additional information (this is why I would use this command and not
raw perf record -e kvm:\*).
> + { SVM_EXIT_MONITOR, "monitor" }, \
> + { SVM_EXIT_MWAIT, "mwait" }, \
> + { SVM_EXIT_XSETBV, "xsetbv" }, \
> + { SVM_EXIT_NPF, "npf" }
All this copy-paste could be avoided by sharing this stuff with the
arch/x86/kvm/ code.
> +static void exit_event_decode_key(struct event_key *key, char decode[20])
> +{
> + const char *exit_reason = get_exit_reason(key->info, key->key);
> +
> + memset(decode, 0, 20);
> + strncpy(decode, exit_reason, 20);
This is a bad pattern to follow when using strncpy(3) because if there
was a strlen(exit_reason) == 20 string then decode[] would not be
NUL-terminated. Right now it's safe but it's better to just use
strlcpy() and drop the memset(3).
> +}
> +
> +static struct kvm_events_ops exit_events = {
> + .is_begain_event = exit_event_begain,
> + .is_end_event = exit_event_end,
> + .get_key = exit_event_get_key,
> + .decode_key = exit_event_decode_key,
> + .name = "VM-EXIT"
> +};
> +
> +#define KVM_TRACE_MMIO_READ_UNSATISFIED 0
> +#define KVM_TRACE_MMIO_READ 1
> +#define KVM_TRACE_MMIO_WRITE 2
> +static bool mmio_event_begain(struct event *event, void *data)
> +{
> + if (!strcmp(event->name, "kvm_mmio")) {
> + long type = raw_field_value(event, "type", data);
> +
> + if (type != KVM_TRACE_MMIO_READ_UNSATISFIED)
> + return true;
> + };
> +
> + return false;
> +}
> +
> +static bool mmio_event_end(struct event *event)
> +{
> + return !strcmp(event->name, "kvm_mmio_done");
> +}
> +
> +static struct event_key mmio_event_get_key(struct event *event, void *data)
> +{
> + struct event_key key;
> +
> + key.key = raw_field_value(event, "gpa", data);
> + key.info = raw_field_value(event, "type", data);
> +
> + return key;
> +}
> +
> +static void mmio_event_decode_key(struct event_key *key, char decode[20])
> +{
> + memset(decode, 0, 20);
> + sprintf(decode, "%#lx:%s", key->key,
> + key->info == KVM_TRACE_MMIO_READ ? "R" : "W");
Please drop the memset and use snprintf(3) instead of sprintf(3). It
places the NUL-terminator and ensures you don't exceed the buffer
size.
Same pattern below.
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