This lets us run the demand paging test on top of a shmem-backed area. In follow-up commits, we'll 1) leverage this new capability to create an alias mapping, and then 2) use the alias mapping to exercise UFFD minor faults.
Signed-off-by: Axel Rasmussen axelrasmussen@google.com --- tools/testing/selftests/kvm/include/test_util.h | 1 + tools/testing/selftests/kvm/lib/kvm_util.c | 15 +++++++++++++++ tools/testing/selftests/kvm/lib/test_util.c | 5 +++++ 3 files changed, 21 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index fade3130eb01..7377f00469ef 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -84,6 +84,7 @@ enum vm_mem_backing_src_type { VM_MEM_SRC_ANONYMOUS_HUGETLB_1GB, VM_MEM_SRC_ANONYMOUS_HUGETLB_2GB, VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB, + VM_MEM_SRC_SHMEM, NUM_SRC_TYPES, };
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index bc405785ac8b..e4a8d0c43c5e 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -757,6 +757,21 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm, if (alignment > 1) region->mmap_size += alignment;
+ region->fd = -1; + if (src_type == VM_MEM_SRC_SHMEM) { + region->fd = memfd_create("kvm_selftest", MFD_CLOEXEC); + TEST_ASSERT(region->fd != -1, + "memfd_create failed, errno: %i", errno); + + ret = ftruncate(region->fd, region->mmap_size); + TEST_ASSERT(ret == 0, "ftruncate failed, errno: %i", errno); + + ret = fallocate(region->fd, + FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, + region->mmap_size); + TEST_ASSERT(ret == 0, "fallocate failed, errno: %i", errno); + } + region->mmap_start = mmap(NULL, region->mmap_size, PROT_READ | PROT_WRITE, vm_mem_backing_src_alias(src_type)->flag, diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index 06ddde068736..c7a265da5090 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -236,6 +236,10 @@ const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i) .name = "anonymous_hugetlb_16gb", .flag = anon_huge_flags | MAP_HUGE_16GB, }, + [VM_MEM_SRC_SHMEM] = { + .name = "shmem", + .flag = MAP_SHARED, + }, }; _Static_assert(ARRAY_SIZE(aliases) == NUM_SRC_TYPES, "Missing new backing src types?"); @@ -253,6 +257,7 @@ size_t get_backing_src_pagesz(uint32_t i)
switch (i) { case VM_MEM_SRC_ANONYMOUS: + case VM_MEM_SRC_SHMEM: return getpagesize(); case VM_MEM_SRC_ANONYMOUS_THP: return get_trans_hugepagesz();