On Tue, Nov 01, 2011 at 10:20:04AM -0600, David Ahern wrote:
>
>
> On 11/01/2011 10:13 AM, Gleb Natapov wrote:
> > On Tue, Nov 01, 2011 at 09:49:19AM -0600, David Ahern wrote:
> >> On 10/30/2011 10:53 AM, Gleb Natapov wrote:
> >>> KVM needs to know perf capability to decide which PMU it can expose to a
> >>> guest.
> >>>
> >>> Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
> >>> ---
> >>> arch/x86/include/asm/perf_event.h | 11 +++++++++++
> >>> arch/x86/kernel/cpu/perf_event.c | 11 +++++++++++
> >>> arch/x86/kernel/cpu/perf_event.h | 2 ++
> >>> arch/x86/kernel/cpu/perf_event_intel.c | 3 +++
> >>> 4 files changed, 27 insertions(+), 0 deletions(-)
> >>>
> >>> diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
> >>> index f61c62f..7d7e57f 100644
> >>> --- a/arch/x86/include/asm/perf_event.h
> >>> +++ b/arch/x86/include/asm/perf_event.h
> >>> @@ -201,7 +201,18 @@ struct perf_guest_switch_msr {
> >>> u64 host, guest;
> >>> };
> >>>
> >>> +struct x86_pmu_capability {
> >>> + int version;
> >>> + int num_counters_gp;
> >>> + int num_counters_fixed;
> >>> + int bit_width_gp;
> >>> + int bit_width_fixed;
> >>> + unsigned int events_mask;
> >>> + int events_mask_len;
> >>> +};
> >>> +
> >>> extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
> >>> +extern void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap);
> >>> #else
> >>> static inline perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
> >>> {
> >>
> >> What about version of perf_get_x86_pmu_capability for CONFIG_PERF_EVENTS
> >> not enabled in host kernel? Next patch for KVM assumes the function is
> >> defined.
> >>
> > As far as I understand it is not possible to build x86 without
> > CONFIG_PERF_EVENTS right now. Actually kvm pmu code depends on
> > CONFIG_PERF_EVENTS been enabled. I can easily provide the stub if
> > needed though.
>
> Right. Originally it could be enabled/disabled. Right now it cannot be,
> but I believe Frederic is working on making it configurable again.
>
> David
Yep. Will Deacon is working on making the breakpoints able to process
pure arch informations (ie: without beeing forced to use the perf attr
as a midlayer to define them).
Once we have that I can seperate the breakpoints implementation from perf
and make it opt-able.
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