[kvm-unit-tests PATCH v2 0/8] x86: fixes for running KUT as EFI on non-QEMU KVM hosts

[Giacomo Mazzola <gmazz@amazon.de>]

This series fixes several issues encountered when running KUT x86 tests
as EFI applications on a KVM-based hypervisor that lacks any ad-hoc
para-virtualized interface (e.g. fw_cfg), on arbitrary VM shapes
(variable CPU count and memory size).

Patches 1-4 fix crashes and faults:
  - Stack size mismatch between EFI and non-EFI paths
  - Memory allocator selecting regions above the 4 GiB identity map
  - #GP on systems without a PMU
  - ISR thunks using rel32 jumps that overflow beyond 2 GiB

Patches 5-6 fix SMP bringup:
  - Replace per-AP serial prints that cause watchdog timeouts on
    large systems
  - Add timeout-based AP detection when fw_cfg is unavailable

Patches 7-8 fix command line handling:
  - Correct the load_options_size byte-to-character conversion
  - Add KUT_ENV= parsing for passing environment variables via the
    command line

Regression-tested by running the full KUT suite under QEMU+KVM+OVMF,
in both ./configure and ./configure --enable-efi. Results are
identical with and without this series.

v1 -> v2:
 - 8/8: reworked per Drew's review. Moved the implementation from
   lib/efi.c to lib/argv.c so the feature is available to non-EFI
   builds as well, use a strncmp() prefix match instead of strstr(),
   shift argv down instead of swapping with the last element so
   argument order is preserved, and drop the redundant isspace()
   check and COMMAND_LINE_SIZE cap.  Retitled accordingly
   ("efi: parse KUT_ENV= from load options into environ" ->
   "lib: parse KUT_ENV= from command line into environ").
   This patch was already posted standalone as v2 and reviewed [2];
   it is included here unchanged so the series is complete.
 - 1/8 - 7/8: unchanged.
 - Picked up Andrew Jones' Reviewed-by on 7/8 and 8/8.
 - Rebased onto current master.

Patches 1-6 received no review in v1, so they are unchanged and still
need a look.  Resending the full series to make it reviewable as a
whole.

[1] v1: https://lore.kernel.org/kvm/20260609140901.95727-1-gmazz@amazon.de/
[2] v2 8/8 standalone: https://lore.kernel.org/kvm/20260625140452.24159-1-gmazz@amazon.de/

Giacomo Mazzola (8):
  x86: efi: use PER_CPU_SIZE for per-CPU stack allocation
  x86: fix EFI memory allocator to clamp regions to 4 GiB
  x86: skip PMU init when no PMU is advertised
  x86: fix ISR thunk to use absolute indirect jump
  x86: replace per-AP bringup prints with a single summary line
  x86: add timeout-based SMP bringup when fw_cfg is unavailable
  efi: fix load_options_size conversion to character count
  lib: parse KUT_ENV= from command line into environ

 lib/argv.c           | 35 +++++++++++++++++++++++++++++++++++
 lib/efi.c            |  2 +-
 lib/x86/apic.c       |  1 -
 lib/x86/isr.c        |  8 +++++---
 lib/x86/setup.c      | 24 ++++++++++++++++++++----
 lib/x86/smp.c        | 31 +++++++++++++++++++++++++++----
 x86/efi/efistart64.S |  2 +-
 7 files changed, 89 insertions(+), 14 deletions(-)


base-commit: 5a221342a025948fa7d84f0c404748f6ba57f3ad
-- 
2.47.3