Commit 0d0b6086 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

perf/x86/intel: Expose existence of callback support to KVM 



Add a "has_callstack" field to the x86_pmu_lbr structure used to pass
information to KVM, and set it accordingly in x86_perf_get_lbr().  KVM
will use has_callstack to avoid trying to create perf LBR events with
PERF_SAMPLE_BRANCH_CALL_STACK on CPUs that don't support callstacks.

Reviewed-by: default avatarMingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20240307011344.835640-3-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 447112d7

arch/x86/events/intel/lbr.c

+1 −0
Original line number Diff line number Diff line
@@ -1693,6 +1693,7 @@ void x86_perf_get_lbr(struct x86_pmu_lbr *lbr) 
	lbr->from = x86_pmu.lbr_from;

	lbr->to = x86_pmu.lbr_to;

	lbr->info = x86_pmu.lbr_info;

	lbr->has_callstack = x86_pmu_has_lbr_callstack();

}

EXPORT_SYMBOL_GPL(x86_perf_get_lbr);

arch/x86/include/asm/perf_event.h

+1 −0
Original line number Diff line number Diff line
@@ -555,6 +555,7 @@ struct x86_pmu_lbr { 
	unsigned int	from;

	unsigned int	to;

	unsigned int	info;

	bool		has_callstack;

};



extern void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap);