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    Subject[PATCH 5/9] KVM: selftests: Align memory region addresses to 1M on s390x
    Date
    On s390x, there is a constraint that memory regions have to be aligned
    to 1M (or running the VM will fail). Introduce a new "alignment" variable
    in the vm_userspace_mem_region_add() function which now can be used for
    both, huge page and s390x alignment requirements.

    Signed-off-by: Thomas Huth <thuth@redhat.com>
    ---
    tools/testing/selftests/kvm/lib/kvm_util.c | 21 ++++++++++++++++-----
    1 file changed, 16 insertions(+), 5 deletions(-)

    diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
    index 08edb8436c47..656df9d5cd4d 100644
    --- a/tools/testing/selftests/kvm/lib/kvm_util.c
    +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
    @@ -559,6 +559,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
    unsigned long pmem_size = 0;
    struct userspace_mem_region *region;
    size_t huge_page_size = KVM_UTIL_PGS_PER_HUGEPG * vm->page_size;
    + size_t alignment;

    TEST_ASSERT((guest_paddr % vm->page_size) == 0, "Guest physical "
    "address not on a page boundary.\n"
    @@ -608,9 +609,20 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
    TEST_ASSERT(region != NULL, "Insufficient Memory");
    region->mmap_size = npages * vm->page_size;

    - /* Enough memory to align up to a huge page. */
    +#ifdef __s390x__
    + /* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
    + alignment = 0x100000;
    +#else
    + alignment = 1;
    +#endif
    +
    if (src_type == VM_MEM_SRC_ANONYMOUS_THP)
    - region->mmap_size += huge_page_size;
    + alignment = huge_page_size;
    +
    + /* Add enough memory to align up if necessary */
    + if (alignment > 1)
    + region->mmap_size += alignment;
    +
    region->mmap_start = mmap(NULL, region->mmap_size,
    PROT_READ | PROT_WRITE,
    MAP_PRIVATE | MAP_ANONYMOUS
    @@ -620,9 +632,8 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
    "test_malloc failed, mmap_start: %p errno: %i",
    region->mmap_start, errno);

    - /* Align THP allocation up to start of a huge page. */
    - region->host_mem = align(region->mmap_start,
    - src_type == VM_MEM_SRC_ANONYMOUS_THP ? huge_page_size : 1);
    + /* Align host address */
    + region->host_mem = align(region->mmap_start, alignment);

    /* As needed perform madvise */
    if (src_type == VM_MEM_SRC_ANONYMOUS || src_type == VM_MEM_SRC_ANONYMOUS_THP) {
    --
    2.21.0
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