Re: [PATCH v2 06/10] KVM: selftests: refactor vm_mem_backing_src_type flags

On Wed, May 19, 2021 at 1:04 PM Axel Rasmussen axelrasmussen@google.com wrote:

Each struct vm_mem_backing_src_alias has a flags field, which denotes the flags used to mmap() an area of that type. Previously, this field never included MAP_PRIVATE | MAP_ANONYMOUS, because vm_userspace_mem_region_add assumed that *all* types would always use those flags, and so it hardcoded them.

In a follow-up commit, we'll add a new type: shmem. Areas of this type must not have MAP_PRIVATE | MAP_ANONYMOUS, and instead they must have MAP_SHARED.

So, refactor things. Make it so that the flags field of struct vm_mem_backing_src_alias really is a complete set of flags, and don't add in any extras in vm_userspace_mem_region_add. This will let us easily tack on shmem.

Signed-off-by: Axel Rasmussen axelrasmussen@google.com

tools/testing/selftests/kvm/lib/kvm_util.c | 5 ++- tools/testing/selftests/kvm/lib/test_util.c | 35 +++++++++++---------- 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 0d6ddee429b9..bc405785ac8b 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -759,9 +759,8 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,

    region->mmap_start = mmap(NULL, region->mmap_size,
                              PROT_READ | PROT_WRITE,

•                             MAP_PRIVATE | MAP_ANONYMOUS
  

•                             | vm_mem_backing_src_alias(src_type)->flag,
  

•                             -1, 0);
  

•                             vm_mem_backing_src_alias(src_type)->flag,
  

•                             region->fd, 0);
  

I don't see the region->fd change mentioned in the patch description or elsewhere in this patch. Is something setting region->fd to -1 or should this be part of another patch in the series?

    TEST_ASSERT(region->mmap_start != MAP_FAILED,
                "test_malloc failed, mmap_start: %p errno: %i",
                region->mmap_start, errno);

diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c index 63d2bc7d757b..06ddde068736 100644 --- a/tools/testing/selftests/kvm/lib/test_util.c +++ b/tools/testing/selftests/kvm/lib/test_util.c @@ -168,70 +168,73 @@ size_t get_def_hugetlb_pagesz(void)

const struct vm_mem_backing_src_alias *vm_mem_backing_src_alias(uint32_t i) {

•   static const int anon_flags = MAP_PRIVATE | MAP_ANONYMOUS;
  

•   static const int anon_huge_flags = anon_flags | MAP_HUGETLB;
  

•   static const struct vm_mem_backing_src_alias aliases[] = {
            [VM_MEM_SRC_ANONYMOUS] = {
                    .name = "anonymous",
  

•                   .flag = 0,
  

•                   .flag = anon_flags,
            },
            [VM_MEM_SRC_ANONYMOUS_THP] = {
                    .name = "anonymous_thp",
  

•                   .flag = 0,
  

•                   .flag = anon_flags,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB] = {
                    .name = "anonymous_hugetlb",
  

•                   .flag = MAP_HUGETLB,
  

•                   .flag = anon_huge_flags,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_16KB] = {
                    .name = "anonymous_hugetlb_16kb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_16KB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_16KB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_64KB] = {
                    .name = "anonymous_hugetlb_64kb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_64KB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_64KB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_512KB] = {
                    .name = "anonymous_hugetlb_512kb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_512KB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_512KB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_1MB] = {
                    .name = "anonymous_hugetlb_1mb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_1MB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_1MB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_2MB] = {
                    .name = "anonymous_hugetlb_2mb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_2MB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_2MB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_8MB] = {
                    .name = "anonymous_hugetlb_8mb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_8MB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_8MB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_16MB] = {
                    .name = "anonymous_hugetlb_16mb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_16MB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_16MB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_32MB] = {
                    .name = "anonymous_hugetlb_32mb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_32MB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_32MB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_256MB] = {
                    .name = "anonymous_hugetlb_256mb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_256MB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_256MB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_512MB] = {
                    .name = "anonymous_hugetlb_512mb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_512MB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_512MB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_1GB] = {
                    .name = "anonymous_hugetlb_1gb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_1GB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_1GB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_2GB] = {
                    .name = "anonymous_hugetlb_2gb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_2GB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_2GB,
            },
            [VM_MEM_SRC_ANONYMOUS_HUGETLB_16GB] = {
                    .name = "anonymous_hugetlb_16gb",
  

•                   .flag = MAP_HUGETLB | MAP_HUGE_16GB,
  

•                   .flag = anon_huge_flags | MAP_HUGE_16GB,
            },
    };
    _Static_assert(ARRAY_SIZE(aliases) == NUM_SRC_TYPES,
  

-- 2.31.1.751.gd2f1c929bd-goog