This series adds a new aarch64 selftest for testing stage 2 fault handling for various combinations of guest accesses (e.g., write, S1PTW), backing sources (e.g., anon), and types of faults (e.g., read on hugetlbfs with a hole, write on a readonly memslot). Each test tries a different combination and then checks that the access results in the right behavior (e.g., uffd faults with the right address and write/read flag). Some interesting combinations are: - loading an instruction leads to a stage 1 page-table-walk that misses on stage 2 because the backing memslot for the page table it not in host memory (a hole was punched right there) and the fault is handled using userfaultfd. The expected behavior is that this leads to a userfaultfd fault marked as a write. See commit c4ad98e4b72c ("KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch") for why that's a write. - a cas (compare-and-swap) on a readonly memslot leads to a failed vcpu run. - write-faulting on a memslot that's marked for userfaultfd handling and dirty logging should result in a uffd fault and having the respective bit set in the dirty log. The first 6 commits of this series add library support. The first one adds a new userfaultfd library (out of demand_paging_test.c). The next 3 add some library functions to get the GPA of a PTE, and to get the fd of a backing source. Commit 6 fixes a leaked fd when using shared backing stores. The last 5 commits add the new selftest, one type of test at a time. It first adds core tests, then uffd, then dirty logging, then readonly memslots tests, and finally combinations of the previous ones (like uffd and dirty logging at the same time). Ricardo Koller (11): KVM: selftests: Add a userfaultfd library KVM: selftests: Add vm_mem_region_get_src_fd library function KVM: selftests: aarch64: Add vm_get_pte_gpa library function KVM: selftests: Add vm_alloc_page_table_in_memslot library function KVM: selftests: aarch64: Export _virt_pg_map with a pt_memslot arg KVM: selftests: Add missing close and munmap in __vm_mem_region_delete KVM: selftests: aarch64: Add aarch64/page_fault_test KVM: selftests: aarch64: Add userfaultfd tests into page_fault_test KVM: selftests: aarch64: Add dirty logging tests into page_fault_test KVM: selftests: aarch64: Add readonly memslot tests into page_fault_test KVM: selftests: aarch64: Add mix of tests into page_fault_test tools/testing/selftests/kvm/Makefile | 3 +- .../selftests/kvm/aarch64/page_fault_test.c | 1461 +++++++++++++++++ .../selftests/kvm/demand_paging_test.c | 227 +-- .../selftests/kvm/include/aarch64/processor.h | 5 + .../selftests/kvm/include/kvm_util_base.h | 2 + .../selftests/kvm/include/userfaultfd_util.h | 46 + .../selftests/kvm/lib/aarch64/processor.c | 36 +- tools/testing/selftests/kvm/lib/kvm_util.c | 37 +- .../selftests/kvm/lib/userfaultfd_util.c | 196 +++ 9 files changed, 1805 insertions(+), 208 deletions(-) create mode 100644 tools/testing/selftests/kvm/aarch64/page_fault_test.c create mode 100644 tools/testing/selftests/kvm/include/userfaultfd_util.h create mode 100644 tools/testing/selftests/kvm/lib/userfaultfd_util.c -- 2.35.1.723.g4982287a31-goog