Re: [PATCH v3 0/9] perf/x86: Don't write PEBS_ENABLED on KVM transitions

From: Peter Zijlstra

Date: Thu Sep 17 2026 - 06:26:20 EST


On Thu, Sep 10, 2026 at 10:56:44AM -0700, Sean Christopherson wrote:
> On Thu, Aug 06, 2026, Sean Christopherson wrote:
> > On Fri, May 08, 2026, Sean Christopherson wrote:
> > > Sean Christopherson (9):
> > > perf/x86/intel: Ensure guest PEBS path doesn't set unwanted
> > > PERF_GLOBAL_CTRL bits
> > > perf/x86/intel: Don't write PEBS_ENABLED on host<=>guest xfers if CPU
> > > has isolation
> > > perf/x86/intel: Don't context switch DS_AREA (and PEBS config) if PEBS
> > > is unused
> > > perf/x86/intel: Make @data a mandatory param for
> > > intel_guest_get_msrs()
> > > perf/x86/intel: Invert names of intel_ctrl_{guest,host}_mask
> > > perf/x86: KVM: Have perf define a dedicated struct for getting guest
> > > PEBS data
> > > perf/x86/intel: KVM: Handle cross-mapped PEBS PMCs entirely within KVM
> > > KVM: VMX: Drop a redundant pmu->global_ctrl check when processing
> > > pebs_enable
> > > KVM: VMX: Only tell perf to enable PEBS counters for fully enabled
> > > PMCs
> > >
> > > arch/x86/events/core.c | 5 +-
> > > arch/x86/events/intel/core.c | 92 +++++++++++++++++++------------
> > > arch/x86/events/intel/lbr.c | 2 +-
> > > arch/x86/events/perf_event.h | 7 ++-
> > > arch/x86/include/asm/kvm_host.h | 9 ---
> > > arch/x86/include/asm/perf_event.h | 11 +++-
> > > arch/x86/kvm/vmx/pmu_intel.c | 28 +++++++---
> > > arch/x86/kvm/vmx/vmx.c | 10 ++--
> > > arch/x86/kvm/vmx/vmx.h | 15 ++++-
> > > 9 files changed, 114 insertions(+), 65 deletions(-)
> >
> > Ping. This still applies on Linus' tree and against tip/master.
>
> Ping again. This fixes a real issue and IMO provides much-needed improvements
> for the KVM<=>perf APIs.

Right, finally got around to staring at them. How did you want them
merged?

AFAICT 2-4 have Fixes tags and should go in perf/urgent, while the rest
goes in perf/core?

/me tries and finds patch 5 doesn't apply.