David Matlack recently added a feature known as eager page splitting to x86 KVM. This feature improves vCPU performance during dirty logging because the splitting operation is moved out of the page fault path, avoiding EPT/NPT violations or allowing the vCPU threads to resolve the violation in the fast path. While this feature is a great performance improvement, it does not have adequate testing in KVM selftests. Add a test to provide coverage of eager page splitting. Patch 1 is a quick refactor to be able to re-use some code from dirty_log_perf_test. Patch 2 adds the actual test. V1->V2: Run test in multiple modes, as suggested by David and Ricardo Cleanups from shameful copy-pasta, as suggested by David Ben Gardon (2): selftests: KVM: Move dirty logging functions to memstress.(c|h) selftests: KVM: Add page splitting test tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/dirty_log_perf_test.c | 84 +----- .../selftests/kvm/include/kvm_util_base.h | 1 + .../testing/selftests/kvm/include/memstress.h | 8 + tools/testing/selftests/kvm/lib/kvm_util.c | 5 + tools/testing/selftests/kvm/lib/memstress.c | 72 +++++ .../kvm/x86_64/page_splitting_test.c | 278 ++++++++++++++++++ 7 files changed, 372 insertions(+), 77 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/page_splitting_test.c -- 2.39.1.405.gd4c25cc71f-goog
