Re: [PATCH v2 00/20] KVM: selftests: PPC pre-enabling

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

On 02/09/26 10:11 PM, Sean Christopherson wrote:
> This is a big pile of cleanups and refactoring to prepare for PPC support in
> KVM selftests.  PPC has paging modes that require multi-page page tables, and
> those page tables need to be naturally aligned.  The original proposal was to
> plumb in an @align param to the page allocators[*], but I didn't love the idea
> of adding another rarely used param to the allocators.
>
> v2:
>   - Collect tags. [Itaru, Bibo]
>   - Use 0x180000 as the min GPA for page table pages on LoongArch, instead of
>     changing every other arch to use 0x200000. [Sashiko, Bibo]
>   - Opportunistically move the vGIC LPI stress test's global "gpa_base" variable
>     into setup_memslot(). [Sashiko]
>
> v1: https://lore.kernel.org/all/20260826230511.972824-1-seanjc@google.com
>
> [*] https://lore.kernel.org/all/df86b5ccdbdafc3509d9538bd5e6796737bab2db.1781093720.git.ritesh.list@gmail.com
>
> Nicholas Piggin (1):
>    KVM: selftests: Use goto instead of do-while to retry finding unused
>      physical pages
>
> Sean Christopherson (19):
>    KVM: selftests: Use MEM_REGION_PT memslot instead of '0' for s390
>      regions/segments
>    KVM: selftests: Use the common minimum GPA for page tables on
>      LoongArch
>    KVM: selftests: Use vm_alloc_page_table() to allocate LoongArch page
>      tables
>    KVM: selftests: Rename "num" param to "nr_pages" for physical page
>      allocators
>    KVM: selftests: Extend page allocator to support naturally aligned
>      allocations
>    KVM: selftests: Make the single-page allocator APIs static inline
>    KVM: selftests: Use the innermost page allocator API in the memslot
>      perf test
>    KVM: selftests: Use the innermost page allocator API in s390's IRQ
>      routing test
>    KVM: selftests: Add a wrapper API to allocate multiple page table
>      pages
>    KVM: selftests: Initialize vm->memslots[] with invalid memslots during
>      creation
>    KVM: selftests: Add APIs to override memory region types with custom
>      memslots
>    KVM: selftests: Add TEST_EXTRA memory region type for "special"
>      memslots
>    KVM: selftests: Use TEST_EXTRA region in arm64's vGIC LPI stress test
>    KVM: selftests: Use TEST_EXTRA region in x86's smaller MAXPHYADDR test
>    KVM: selftests: Use TEST_EXTRA region in set memory region test
>    KVM: selftests: Take the memory region type, not memslot, in page
>      allocators
>    KVM: selftests: Use TEST_ASSERT(), not assert(), in
>      vm_get_mem_region()
>    KVM: selftests: Automatically pick min_gpa for allocations based on
>      region type
>    KVM: selftests: Add arch hook to force page tables to be naturally
>      aligned
>
>   .../selftests/kvm/arm64/page_fault_test.c     |  18 ++-
>   .../selftests/kvm/arm64/vgic_lpi_stress.c     |  21 ++-
>   .../testing/selftests/kvm/include/kvm_util.h  | 106 +++++++++++++--
>   tools/testing/selftests/kvm/include/x86/smm.h |   2 +-
>   .../selftests/kvm/lib/arm64/processor.c       |   4 +-
>   tools/testing/selftests/kvm/lib/kvm_util.c    | 127 +++++++++++-------
>   .../selftests/kvm/lib/loongarch/processor.c   |   5 +-
>   .../selftests/kvm/lib/riscv/processor.c       |   4 +-
>   .../selftests/kvm/lib/s390/processor.c        |   7 +-
>   .../testing/selftests/kvm/lib/x86/processor.c |  15 ++-
>   .../testing/selftests/kvm/memslot_perf_test.c |   3 +-
>   tools/testing/selftests/kvm/s390/cmma_test.c  |  19 +--
>   .../testing/selftests/kvm/s390/irq_routing.c  |   2 +-
>   .../selftests/kvm/set_memory_region_test.c    |   8 +-
>   .../x86/smaller_maxphyaddr_emulation_test.c   |   9 +-
>   15 files changed, 221 insertions(+), 129 deletions(-)
>
>
> base-commit: 76671054f9a1ff6abb976583cd8da37650acdc97

Hi Sean,

Thanks for working on this patch series. I tested this series (v2) as a 
base
for Ritesh's PowerPC KVM selftest series (v5) [1] on two real 
PowerPC(ppc64le)
PowerVM & PowerNV systems. Your patches applied cleanly and the core 
infrastructure
changes worked correctly on PowerPC — exactly the foundation Ritesh's 
series needed.


Ritesh's patch series : 
https://lore.kernel.org/linuxppc-dev/cover.1790101179.git.ritesh.list@gmail.com/

Full test suite summary (make run_tests):
-----------------------------------------
                                    LPAR    bare-metal
   demand_paging_test               PASS      PASS
   dirty_log_test                   PASS      PASS
   dirty_log_perf_test              PASS      PASS
   guest_print_test                 PASS      PASS
   hardware_disable_test            PASS      PASS
   kvm_binary_stats_test            PASS      PASS
   kvm_create_max_vcpus             PASS      PASS
   kvm_page_table_test              PASS      PASS
   set_memory_region_test           PASS      PASS
   memslot_modification_stress_test PASS      PASS
   memslot_perf_test                PASS      PASS
   access_tracking_perf_test        PASS      PASS
   irqfd_test                       SKIP      SKIP
   vm_types_test                    SKIP      SKIP
   --------------------------------------------------
   Total                         12 PASS   12 PASS
                                  2 SKIP    2 SKIP

My Detailed testing analysis for your patches on PowerPC (ppc64le):
-------------------------------------------------
Patches 1-5 [Page allocator and memslot refactoring]
   Core page allocator and memslot infrastructure exercised by all 14
   tests on both systems — no regressions observed.

Patches 6-10 [Extended page allocator APIs]
   Exercised via kvm_create_max_vcpus and memslot_perf_test on both
   systems — APIs work correctly on PowerPC.

Patches 11-13, 16 [Memslot initialization and TEST_EXTRA region]
   set_memory_region_test and memslot_modification_stress_test ran
   successfully on both systems — memslot init, TEST_EXTRA region, and
   its usage in set_memory_region_test all working correctly.

Patch 17 [Memory region type API]
   Exercised by set_memory_region_test — PASS on both systems.

Patch 18 [Use TEST_ASSERT() in kvm_util.c]
   Exercised by all tests — no assertion failures observed.

Patch 19 [Auto-pick min_gpa for PowerPC]
   This is the critical patch for PPC — guest physical test memory
   was correctly placed above 256M on both systems:
     LPAR:       guest physical test memory: [0xfffffbfff0000, 
0xfffffffff0000)
     bare-metal: guest physical test memory: [0xfffffbfff0000, 
0xfffffffff0000)

Patch 20 [Add arch hook to force page table setup]
   lib/powerpc/processor.c correctly hooks into this — guest page
   tables set up correctly on both systems.

Note: Patches 14 and 15 (arm64/x86-specific TEST_EXTRA usage) were
not exercised as those tests don't build on PowerPC — as expected.


Please feel free to add :

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

Thank you,
Anushree Mathur


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