From: Sean Christopherson <[email protected]> Check that a valid fd provided to mmap() must be accompanied by MAP_SHARED.
With an invalid fd (usually used for anonymous mappings), there are no constraints on mmap() flags. Add this check to make sure that when a guest_memfd is used as region->fd, the flag provided to mmap() will include MAP_SHARED. Signed-off-by: Sean Christopherson <[email protected]> [Rephrase assertion message.] Signed-off-by: Ackerley Tng <[email protected]> --- tools/testing/selftests/kvm/lib/kvm_util.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 61adfd7e623c..aec7b24418ab 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -1062,6 +1062,9 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, src_type == VM_MEM_SRC_SHARED_HUGETLB); } + TEST_ASSERT(region->fd == -1 || backing_src_is_shared(src_type), + "A valid fd provided to mmap() must be accompanied by MAP_SHARED."); + region->mmap_start = __kvm_mmap(region->mmap_size, PROT_READ | PROT_WRITE, vm_mem_backing_src_alias(src_type)->flag, region->fd, mmap_offset); -- 2.53.0.rc1.225.gd81095ad13-goog
