[PATCH v5 0/5] perf/x86: Some minor changes to support guest Arch LBR

[Like Xu]

Hi Peter,

Please help review these minor perf/x86 changes in this patch set,
and we need some of them to support Guest Architectural LBR in KVM.

This version keeps reserve_lbr_buffers() as is because the LBR xsave
buffer is a per-CPU buffer, not a per-event buffer. We only need to
allocate the buffer once when initializing the first event. 

If you are interested in the KVM emulation, please check
https://lore.kernel.org/kvm/20210314155225.206661-1-like.xu@xxxxxxxxxxxxxxx/

Please check more details in each commit and feel free to comment.

Previous:
https://lore.kernel.org/lkml/20210322060635.821531-1-like.xu@xxxxxxxxxxxxxxx/

v4->v5 Changelog:
- Add "Tested-by: Kan Liang"
- Make the commit message simpler
- Make check_msr() to ignore msr==0 
- Use kmem_cache_alloc_node() [Namhyung]

Like Xu (5):
  perf/x86/intel: Fix the comment about guest LBR support on KVM
  perf/x86/lbr: Simplify the exposure check for the LBR_INFO registers
  perf/x86: Skip checking MSR for MSR 0x000
  perf/x86/lbr: Move cpuc->lbr_xsave allocation out of sleeping region
  perf/x86: Move ARCH_LBR_CTL_MASK definition to include/asm/msr-index.h

 arch/x86/events/core.c           |  8 +++++---
 arch/x86/events/intel/bts.c      |  2 +-
 arch/x86/events/intel/core.c     |  7 +++----
 arch/x86/events/intel/lbr.c      | 29 ++++++++++++++++++-----------
 arch/x86/events/perf_event.h     |  8 +++++++-
 arch/x86/include/asm/msr-index.h |  1 +
 6 files changed, 35 insertions(+), 20 deletions(-)

-- 
2.29.2