Re: [PATCH v4 0/3] KVM: selftests: add powerpc support

[Anushree Mathur <anushree.mathur2@ibm.com>]

On 11/09/26 10:18 AM, Ritesh Harjani (IBM) wrote:
> PATCH v3 -> PATCH v4:
> ==================
> - Rebased on top of Sean's new page allocator patch series v2 [1]
>    This allowed to drop and patch-2 since it will now come from Sean's
>    v2.
> - Addressed review comments from Sean - squashed patches 6-10 in patch-1 of
>    this.
> - Dropped patch-5 to print vcpu_id when KVM_CREATE_VCPU ioctl fails.
> - Added additional patch-3 to this series to allow dirty_log_test to run on all
>    big-endian machines.
>
> [1]: https://lore.kernel.org/kvm/20260902164123.2546762-1-seanjc@google.com/
> [v3]: https://lore.kernel.org/linuxppc-dev/2d2c46be7f051c7f1c645afaec67f57067d37a81.1781093720.git.ritesh.list@gmail.com/
>
> Testing updates:
> ================
> I have done some fair amount of testing of the selftests both on real HW and
> using various combinations on qemu (powernv+LE (default), pseries+cap-nested-hv,
> pseries+cap-nested-papr, powernv+BE). There were few powerpc kvm kernel fixes
> which were identified as part of this work. I will send those patches separately
> as those anyway needs to go in separately.
>
> <pasted snippet of cover letter from previous versions>
> =======================================================
>
> Hi All,
>
> This series primarly adds KVM selftests support for powerpc (64-bit, BookS,
> radix MMU).
>
> This patch series is originally Nick's work. I have mainly only rebased it on
> the latest upstream tree. Since the rebase required few changes to all the four
> patches (Patch 1-4), I have dropped the earlier Acked-by from Michael Ellerman.
>
> Since the last series was posted three years ago [1], I am resetting the version
> to RFC. This rebase was done as part of a larger effort to improve the selftests
> infrastructure for Linux on PowerPC tree. Thanks to Harsh and Maddy for their
> help on this.
>
> Nicholas Piggin (1):
>    KVM: PPC: selftests: add support for powerpc
>
> Ritesh Harjani (IBM) (2):
>    KVM: PPC: selftests: powerpc enable kvm_create_max_vcpus test
>    KVM: selftests: Use LE bitops for dirty bitmaps on all big-endian
>      hosts
>
>   MAINTAINERS                                   |   2 +
>   tools/testing/selftests/kvm/Makefile          |   2 +-
>   tools/testing/selftests/kvm/Makefile.kvm      |  10 +
>   tools/testing/selftests/kvm/dirty_log_test.c  |  12 +-
>   .../testing/selftests/kvm/include/kvm_util.h  |   9 +
>   .../selftests/kvm/include/powerpc/hcall.h     |  17 +
>   .../kvm/include/powerpc/kvm_util_arch.h       |  22 +
>   .../selftests/kvm/include/powerpc/ppc_asm.h   |  32 ++
>   .../selftests/kvm/include/powerpc/processor.h |  39 ++
>   .../selftests/kvm/include/powerpc/ucall.h     |  21 +
>   .../selftests/kvm/kvm_create_max_vcpus.c      |   8 +-
>   tools/testing/selftests/kvm/lib/guest_modes.c |  20 +-
>   tools/testing/selftests/kvm/lib/kvm_util.c    |   8 +
>   .../selftests/kvm/lib/powerpc/handlers.S      |  93 ++++
>   .../testing/selftests/kvm/lib/powerpc/hcall.c |  45 ++
>   .../selftests/kvm/lib/powerpc/processor.c     | 512 ++++++++++++++++++
>   .../testing/selftests/kvm/lib/powerpc/ucall.c |  22 +
>   17 files changed, 862 insertions(+), 12 deletions(-)
>   create mode 100644 tools/testing/selftests/kvm/include/powerpc/hcall.h
>   create mode 100644 tools/testing/selftests/kvm/include/powerpc/kvm_util_arch.h
>   create mode 100644 tools/testing/selftests/kvm/include/powerpc/ppc_asm.h
>   create mode 100644 tools/testing/selftests/kvm/include/powerpc/processor.h
>   create mode 100644 tools/testing/selftests/kvm/include/powerpc/ucall.h
>   create mode 100644 tools/testing/selftests/kvm/lib/powerpc/handlers.S
>   create mode 100644 tools/testing/selftests/kvm/lib/powerpc/hcall.c
>   create mode 100644 tools/testing/selftests/kvm/lib/powerpc/processor.c
>   create mode 100644 tools/testing/selftests/kvm/lib/powerpc/ucall.c
>
> --
> 2.39.5
>
Hi Ritesh,
Thanks for working on this enablement. I have tested kvm selftests after 
applying this patch on top of Sean's patch as mentioned and even I 
applied this patch for the kvm_create_max_vcpus issue as rc=-56 
"https://lore.kernel.org/linuxppc-dev/cover.1789099725.git.ritesh.list@gmail.com/" 
But still few tests got failed. Providing a summary below:

System details where I tested this : PowerVM P11 (ppc64le) KVM enabled lpar!

Test Results:
=============

PASS: demand_paging_test
PASS: dirty_log_test (dirty-log mode, 4K + 64K pages, 32 iterations)
PASS: guest_print_test
PASS: kvm_binary_stats_test (4/4 subtests)
PASS: kvm_page_table_test (4K + 64K pages)
PASS: set_memory_region_test
PASS: memslot_modification_stress_test (4K + 64K pages)
PASS: memslot_perf_test
PASS: dirty_log_perf_test (4K + 64K pages)

SKIP: irqfd_test
   - kvm_arch_has_default_irqchip() not yet implemented for PowerPC

SKIP: vm_types_test
   - KVM_CAP_VM_TYPES not supported on PowerPC

Failures seen for the following tests

FAIL: kvm_create_max_vcpus
   - RFC patch-3 partially helps: KVM_CAP_MAX_VCPU_ID correctly
     capped from 16384 to 2048.
   - But vCPU creation still fails with rc=-44 below the 2048 limit.
   - dmesg: KVM: Create Guest vcpu hcall failed, rc=-44

for the above test in dmesg I saw the following error everytime I ran 
this test

dmesg -w
[ 2640.213798] KVM: Create Guest vcpu hcall failed, rc=-44
[ 2923.048989] KVM: Create Guest hcall failed, rc=-44
[ 3650.642771] KVM: Create Guest vcpu hcall failed, rc=-44

FAIL: hardware_disable_test
   - KVM_CREATE_VM fails with ENOMEM
   - dmesg: KVM: Create Guest vcpu hcall failed, rc=-44
   - Likely the same underlying hcall issue as kvm_create_max_vcpus.

FAIL: access_tracking_perf_test
   - Too many idle pages (245385 out of 262144)
   - errno=4 (Interrupted system call)
   - page_idle tracking may not be fully supported on PowerPC yet.


I believe these issues might be real kernel issue. If you plan to send 
fixed please feel free to add my Reported-by:

Reported-by: Anushree Mathur <anushree.mathur@linux.ibm.com>

Thank you,
Anushree Mathur