This series comes as a follow-up of discussions held in
[PATCH v6 00/11] Mitigation of "failed to load
cpu:cpreg_vmstate_array_len" migration failures
(https://lore.kernel.org/all/20260126165445.3033335-1-eric.auger@redhat.com/)

It only covers the improvement of the traces. Actual mitigations
are handled in a follow-up series:
Mitigation of "failed to load cpu:cpreg_vmstate_array_len" (v8)

When the number of CPU registers received in an incoming migration
stream is bigger than the number of CPU registers seen by the
destination we currently get the following error:

"failed to load cpu:cpreg_vmstate_array_len"

This series removes this cryptic message and explicitly outputs
which spurious registers cause the failures.

---

Available at:
https://github.com/eauger/qemu/tree/cpreg_vmstate_array_len_traces_v3_mitig_v2

v2 -> v3:
- clear the vmstate array pointers on post_save()
- improve the print_register_name comment
- Collecting remaining R-b's

v1 -> v2:
- Tool all comments from Peter on v1. See individual history logs
- Also added last patch which was previously included in the follow-up
  mitigation series ([PATCH v7 0/7] Mitigation of "failed to load
  cpu:cpreg_vmstate_array_len" migration failures) but actually belongs
  to those functional changes.


Eric Auger (7):
  vmstate: Introduce VMSTATE_VARRAY_INT32_ALLOC
  target/arm/machine: Use VMSTATE_VARRAY_INT32_ALLOC for cpreg arrays
  target/arm/kvm: Export kvm_print_register_name()
  target/arm/kvm: Tweak print_register_name() for arm64 system register
  target/arm/machine: Trace cpreg names which do not match on migration
  target/arm/machine: Trace all register mismatches
  target/arm/machine: Fix detection of unknown incoming cpregs

 include/migration/vmstate.h |  10 ++++
 target/arm/kvm_arm.h        |   9 +++
 target/arm/helper.c         |   5 --
 target/arm/kvm-stub.c       |   5 ++
 target/arm/kvm.c            |   9 +--
 target/arm/machine.c        | 115 ++++++++++++++++++++++++++++++------
 target/arm/whpx/whpx-all.c  |   7 ---
 target/arm/trace-events     |   3 +
 8 files changed, 127 insertions(+), 36 deletions(-)

-- 
2.53.0

On Wed, 4 Mar 2026 at 10:16, Eric Auger <eric.auger@redhat.com> wrote:
>
> This series comes as a follow-up of discussions held in
> [PATCH v6 00/11] Mitigation of "failed to load
> cpu:cpreg_vmstate_array_len" migration failures
> (https://lore.kernel.org/all/20260126165445.3033335-1-eric.auger@redhat.com/)
>
> It only covers the improvement of the traces. Actual mitigations
> are handled in a follow-up series:
> Mitigation of "failed to load cpu:cpreg_vmstate_array_len" (v8)
>
> When the number of CPU registers received in an incoming migration
> stream is bigger than the number of CPU registers seen by the
> destination we currently get the following error:
>
> "failed to load cpu:cpreg_vmstate_array_len"
>
> This series removes this cryptic message and explicitly outputs
> which spurious registers cause the failures.
>
> ---



Applied to target-arm.next, thanks.

-- PMM