Commit 61bcd360 authored by David Matlack's avatar David Matlack Committed by Paolo Bonzini
Browse files

KVM: x86/mmu: Fix use of enums in trace_fast_page_fault 



Enum values have to be exported to userspace since the formatting is not
done in the kernel. Without doing this perf maps RET_PF_FIXED and
RET_PF_SPURIOUS to 0, which results in incorrect output:

  $ perf record -a -e kvmmmu:fast_page_fault --filter "ret==3" -- ./access_tracking_perf_test
  $ perf script | head -1
   [...] new 610006048d25877 spurious 0 fixed 0  <------ should be 1

Fix this by exporting the enum values to userspace with TRACE_DEFINE_ENUM.

Fixes: c4371c2a ("KVM: x86/mmu: Return unique RET_PF_* values if the fault was fixed")
Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
Message-Id: <20210713220957.3493520-3-dmatlack@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 76cd325e

arch/x86/kvm/mmu/mmu_internal.h

+3 −0
Original line number Diff line number Diff line
@@ -140,6 +140,9 @@ void kvm_flush_remote_tlbs_with_address(struct kvm *kvm, 
 * RET_PF_INVALID: the spte is invalid, let the real page fault path update it.

 * RET_PF_FIXED: The faulting entry has been fixed.

 * RET_PF_SPURIOUS: The faulting entry was already fixed, e.g. by another vCPU.

 *

 * Any names added to this enum should be exported to userspace for use in

 * tracepoints via TRACE_DEFINE_ENUM() in mmutrace.h

 */

enum {

	RET_PF_RETRY = 0,

arch/x86/kvm/mmu/mmutrace.h

+6 −0
Original line number Diff line number Diff line
@@ -54,6 +54,12 @@ 
	{ PFERR_RSVD_MASK, "RSVD" },	\

	{ PFERR_FETCH_MASK, "F" }



TRACE_DEFINE_ENUM(RET_PF_RETRY);

TRACE_DEFINE_ENUM(RET_PF_EMULATE);

TRACE_DEFINE_ENUM(RET_PF_INVALID);

TRACE_DEFINE_ENUM(RET_PF_FIXED);

TRACE_DEFINE_ENUM(RET_PF_SPURIOUS);



/*

 * A pagetable walk has started

 */