Commit c9befd59 authored by Axel Rasmussen's avatar Axel Rasmussen Committed by Paolo Bonzini
Browse files

KVM: selftests: add shmem backing source type 



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: default avatarAxel Rasmussen <axelrasmussen@google.com>
Message-Id: <20210519200339.829146-8-axelrasmussen@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b3784bc2

tools/testing/selftests/kvm/include/test_util.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

};

tools/testing/selftests/kvm/lib/kvm_util.c

+16 −1
Original line number Diff line number Diff line
@@ -847,10 +847,25 @@ 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,

				  -1, 0);

				  region->fd, 0);

	TEST_ASSERT(region->mmap_start != MAP_FAILED,

		    "test_malloc failed, mmap_start: %p errno: %i",

		    region->mmap_start, errno);

tools/testing/selftests/kvm/lib/test_util.c

+5 −0
Original line number Diff line number Diff line
@@ -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();