[PATCH v2 0/4] trace_hyp_printk() for pKVM/nVHE hypervisor

[Vincent Donnefort <vdonnefort@google.com>]

Hi all,

This series adds a hypervisor event "hyp_printk" which enables
developers to log pretty much anything into the hypervisor tracing
buffer, just like the kernel function trace_printk().

This enables rich logging from the hypervisor, while leaving all the
string parsing burden to the kernel. This has been the main way of
debugging pKVM in Android.

Even though not strictly related to trace_hyp_printk, I have added the
following two patches:

  * KVM: arm64: Allow early calls to pKVM host_share/unshare_hyp

    This one mainly intends to support one of the new features I have
    posted here [1], which allows to enable tracing as early as
    possible. I have added it here to limit cross-posting.

  * KVM: arm64: Move kvm_define_hypevents.h to arch/arm64/kvm/

    This one is just a cleanup.

[1] https://lore.kernel.org/all/20260605163825.1762953-1-vdonnefort@google.com/

Changelog:

v2:
  - Collect Fuad's tags
  - Rebase on 7.2-rc2
  - Warn when trace_hyp_printk callsites are exhausted (Fuad)

v1 (https://lore.kernel.org/all/20260612142245.1015744-1-vdonnefort@google.com/)

Vincent Donnefort (4):
  KVM: arm64: Allow early calls to pKVM host_share/unshare_hyp
  KVM: arm64: Move kvm_define_hypevents.h to arch/arm64/kvm/
  tracing/remotes: Add REMOTE_EVENT_CUSTOM_PRINTK() helper
  KVM: arm64: Add hyp_printk event to nVHE/pKVM hyp

 arch/arm64/include/asm/kvm_asm.h              |  4 +-
 arch/arm64/include/asm/kvm_hypevents.h        | 14 ++++
 arch/arm64/include/asm/kvm_hyptrace.h         |  8 +++
 arch/arm64/kernel/image-vars.h                |  1 +
 arch/arm64/kernel/vmlinux.lds.S               |  4 ++
 .../define_hypevents.h}                       |  0
 .../kvm/hyp/include/nvhe/define_events.h      |  2 -
 arch/arm64/kvm/hyp/include/nvhe/trace.h       | 65 +++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/events.c              |  6 ++
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            |  2 +-
 arch/arm64/kvm/hyp_trace.c                    | 63 +++++++++++++++++-
 include/trace/define_remote_events.h          | 19 +++++-
 12 files changed, 179 insertions(+), 9 deletions(-)
 rename arch/arm64/{include/asm/kvm_define_hypevents.h => kvm/define_hypevents.h} (100%)


base-commit: 8cdeaa50eae8dad34885515f62559ee83e7e8dda
-- 
2.55.0.795.g602f6c329a-goog