[PATCH v3 00/12] KVM: selftests: Add more syscall wrappers, fix hardware_disable_test
From: Sean Christopherson
Date: Fri Jul 31 2026 - 15:56:24 EST
Third time's a charm. Sorry for the spam.
Buried in the middle of this is a fix for the hardware_disable_test where
it can end up with a runtime of multiple minutes when running a preemptible
kernels on a large NUMA system. Turns out my analysis/guess in v1 was wrong;
the problem isn't direct CPU contention, it's that letting the workers do any
amount of "real" work on any CPUs leads to pthread_create() slowdowns from
the perspective of the caller.
The vast, vast majority of the changes are adding kvm_xxx() syscall wrappers
so that tests don't need to manually assert that a syscall succeeds (the
hardware disable test had some ugly equivalents).
v3:
- Key off _GNU_SOURCE, not __USE_GNU. [Sashiko]
- Clear consumed CPUs from the allowed set. [Sashiko]
- Assert that settings affinity attributes succeeds. [Sasiko]
v2:
- https://lore.kernel.org/all/20260731170619.2620845-1-seanjc%40google.com
- pause() the child after creating workers so as not to busy loop, and to
maintain equivalent functionality. [Sashiko]
- Don't bother pinning the parent of immediate child, and instead focus on
affining workers to their CPUs asap.
v1: https://lore.kernel.org/all/20260730191908.2084803-1-seanjc@xxxxxxxxxx
Sean Christopherson (12):
KVM: selftests: Add a KVM syscall wrapper for sched_setaffinity()
KVM: selftests: Set threads CPU affinity before doing work in hardware
disable test
KVM: selftests: Pre-set threads affinity in hardware disable test when
possible
KVM: selftests: Return the target CPU from pin_task_to_random_cpu()
KVM: selftests: Extract picking of random CPU from cpu_set_t to
separate API
KVM: selftests: Affine threads to random CPUs in hardware disable test
KVM: selftests: Drop unreachable, dead code from hardware disable test
KVM: selftests: Add KVM syscall wrapper for pthread_create()
KVM: selftests: Add KVM syscall wrappers for pthread_{cancel,join}()
KVM: selftests: Add helper APIs to cancel+join pthreads
KVM: selftests: Add KVM syscall wrappers for
pthread_{g,s}etaffinity_np()
KVM: selftests: Clean up global constants in hardware disable test
tools/testing/selftests/kvm/arch_timer.c | 18 +--
tools/testing/selftests/kvm/arm64/vgic_irq.c | 14 +--
.../selftests/kvm/arm64/vgic_lpi_stress.c | 8 +-
tools/testing/selftests/kvm/dirty_log_test.c | 4 +-
.../selftests/kvm/hardware_disable_test.c | 109 ++++++++----------
.../selftests/kvm/include/kvm_syscalls.h | 48 ++++++++
.../testing/selftests/kvm/include/kvm_util.h | 11 +-
tools/testing/selftests/kvm/irq_test.c | 4 +-
tools/testing/selftests/kvm/irqfd_test.c | 4 +-
.../selftests/kvm/kvm_page_table_test.c | 6 +-
tools/testing/selftests/kvm/lib/kvm_util.c | 10 +-
tools/testing/selftests/kvm/lib/memstress.c | 4 +-
.../selftests/kvm/lib/userfaultfd_util.c | 7 +-
.../testing/selftests/kvm/memslot_perf_test.c | 4 +-
tools/testing/selftests/kvm/mmu_stress_test.c | 4 +-
.../selftests/kvm/pre_fault_memory_test.c | 4 +-
tools/testing/selftests/kvm/rseq_test.c | 12 +-
tools/testing/selftests/kvm/s390/memop.c | 4 +-
.../selftests/kvm/set_memory_region_test.c | 6 +-
tools/testing/selftests/kvm/steal_time.c | 6 +-
tools/testing/selftests/kvm/x86/hyperv_ipi.c | 32 +----
.../selftests/kvm/x86/hyperv_tlb_flush.c | 30 +----
.../kvm/x86/private_mem_conversions_test.c | 4 +-
.../kvm/x86/private_mem_kvm_exits_test.c | 7 +-
.../selftests/kvm/x86/recalc_apic_map_test.c | 5 +-
.../selftests/kvm/x86/sev_migrate_tests.c | 4 +-
.../selftests/kvm/x86/sync_regs_test.c | 5 +-
.../selftests/kvm/x86/tsc_scaling_sync.c | 4 +-
.../selftests/kvm/x86/xapic_ipi_test.c | 31 +----
.../selftests/kvm/x86/xen_shinfo_test.c | 10 +-
30 files changed, 187 insertions(+), 232 deletions(-)
base-commit: 3c7d7f908d574277a845423ec32250a8d8df44c8
--
2.55.0.508.g3f0d502094-goog