[PATCH 5/6] KVM: selftests: Add wrappers for mmap() and munmap() to assert success

Sean Christopherson
2025-09-26T16:31:30Z

Add and use wrappers for mmap() and munmap() that assert success to reduce
a significant amount of boilerplate code, to ensure all tests assert on
failure, and to provide consistent error messages on failure.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
.../testing/selftests/kvm/guest_memfd_test.c | 21 +++------
.../testing/selftests/kvm/include/kvm_util.h | 25 +++++++++++
tools/testing/selftests/kvm/lib/kvm_util.c | 44 +++++++------------
tools/testing/selftests/kvm/mmu_stress_test.c | 5 +--
.../selftests/kvm/s390/ucontrol_test.c | 16 +++----
.../selftests/kvm/set_memory_region_test.c | 17 ++++---
6 files changed, 64 insertions(+), 64 deletions(-)

diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index 5a50a28ce1fa..5dd40b77dc07 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -50,8 +50,7 @@ static void test_mmap_supported(int fd, size_t total_size)
mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
TEST_ASSERT(mem == MAP_FAILED, "Copy-on-write not allowed by guest_memfd.");

- mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- TEST_ASSERT(mem != MAP_FAILED, "mmap() for guest_memfd should succeed.");
+ mem = kvm_mmap(total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);

memset(mem, val, total_size);
for (i = 0; i < total_size; i++)
@@ -70,8 +69,7 @@ static void test_mmap_supported(int fd, size_t total_size)
for (i = 0; i < total_size; i++)
TEST_ASSERT_EQ(READ_ONCE(mem[i]), val);

- ret = munmap(mem, total_size);
- TEST_ASSERT(!ret, "munmap() should succeed.");
+ kvm_munmap(mem, total_size);
}

static sigjmp_buf jmpbuf;
@@ -89,10 +87,8 @@ static void test_fault_overflow(int fd, size_t total_size)
const char val = 0xaa;
char *mem;
size_t i;
- int ret;

- mem = mmap(NULL, map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- TEST_ASSERT(mem != MAP_FAILED, "mmap() for guest_memfd should succeed.");
+ mem = kvm_mmap(map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);

sigaction(SIGBUS, &sa_new, &sa_old);
if (sigsetjmp(jmpbuf, 1) == 0) {
@@ -104,8 +100,7 @@ static void test_fault_overflow(int fd, size_t total_size)
for (i = 0; i < total_size; i++)
TEST_ASSERT_EQ(READ_ONCE(mem[i]), val);

- ret = munmap(mem, map_size);
- TEST_ASSERT(!ret, "munmap() should succeed.");
+ kvm_munmap(mem, map_size);
}

static void test_mmap_not_supported(int fd, size_t total_size)
@@ -347,10 +342,9 @@ static void test_guest_memfd_guest(void)
GUEST_MEMFD_FLAG_DEFAULT_SHARED);
vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL, fd, 0);

- mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed");
+ mem = kvm_mmap(size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
memset(mem, 0xaa, size);
- munmap(mem, size);
+ kvm_munmap(mem, size);

virt_pg_map(vm, gpa, gpa);
vcpu_args_set(vcpu, 2, gpa, size);
@@ -358,8 +352,7 @@ static void test_guest_memfd_guest(void)

TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE);

- mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed");
+ mem = kvm_mmap(size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);
for (i = 0; i < size; i++)
TEST_ASSERT_EQ(mem[i], 0xff);

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 23a506d7eca3..1c68ff0fb3fb 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -278,6 +278,31 @@ static inline bool kvm_has_cap(long cap)
#define __KVM_SYSCALL_ERROR(_name, _ret) \
"%s failed, rc: %i errno: %i (%s)", (_name), (_ret), errno, strerror(errno)

+static inline void *__kvm_mmap(size_t size, int prot, int flags, int fd,
+ off_t offset)
+{
+ void *mem;
+
+ mem = mmap(NULL, size, prot, flags, fd, offset);
+ TEST_ASSERT(mem != MAP_FAILED, __KVM_SYSCALL_ERROR("mmap()",
+ (int)(unsigned long)MAP_FAILED));
+
+ return mem;
+}
+
+static inline void *kvm_mmap(size_t size, int prot, int flags, int fd)
+{
+ return __kvm_mmap(size, prot, flags, fd, 0);
+}
+
+static inline void kvm_munmap(void *mem, size_t size)
+{
+ int ret;
+
+ ret = munmap(mem, size);
+ TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+}
+
/*
* Use the "inner", double-underscore macro when reporting errors from within
* other macros so that the name of ioctl() and not its literal numeric value
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index c3f5142b0a54..da754b152c11 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -770,13 +770,11 @@ static void vm_vcpu_rm(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
int ret;

if (vcpu->dirty_gfns) {
- ret = munmap(vcpu->dirty_gfns, vm->dirty_ring_size);
- TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+ kvm_munmap(vcpu->dirty_gfns, vm->dirty_ring_size);
vcpu->dirty_gfns = NULL;
}

- ret = munmap(vcpu->run, vcpu_mmap_sz());
- TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+ kvm_munmap(vcpu->run, vcpu_mmap_sz());

ret = close(vcpu->fd);
TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("close()", ret));
@@ -810,20 +808,16 @@ void kvm_vm_release(struct kvm_vm *vmp)
static void __vm_mem_region_delete(struct kvm_vm *vm,
struct userspace_mem_region *region)
{
- int ret;
-
rb_erase(&region->gpa_node, &vm->regions.gpa_tree);
rb_erase(&region->hva_node, &vm->regions.hva_tree);
hash_del(&region->slot_node);

sparsebit_free(&region->unused_phy_pages);
sparsebit_free(&region->protected_phy_pages);
- ret = munmap(region->mmap_start, region->mmap_size);
- TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+ kvm_munmap(region->mmap_start, region->mmap_size);
if (region->fd >= 0) {
/* There's an extra map when using shared memory. */
- ret = munmap(region->mmap_alias, region->mmap_size);
- TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+ kvm_munmap(region->mmap_alias, region->mmap_size);
close(region->fd);
}
if (region->region.guest_memfd >= 0)
@@ -1080,12 +1074,9 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
region->fd = kvm_memfd_alloc(region->mmap_size,
src_type == VM_MEM_SRC_SHARED_HUGETLB);

- region->mmap_start = mmap(NULL, region->mmap_size,
- PROT_READ | PROT_WRITE,
- vm_mem_backing_src_alias(src_type)->flag,
- region->fd, 0);
- TEST_ASSERT(region->mmap_start != MAP_FAILED,
- __KVM_SYSCALL_ERROR("mmap()", (int)(unsigned long)MAP_FAILED));
+ region->mmap_start = kvm_mmap(region->mmap_size, PROT_READ | PROT_WRITE,
+ vm_mem_backing_src_alias(src_type)->flag,
+ region->fd);

TEST_ASSERT(!is_backing_src_hugetlb(src_type) ||
region->mmap_start == align_ptr_up(region->mmap_start, backing_src_pagesz),
@@ -1156,12 +1147,10 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,

/* If shared memory, create an alias. */
if (region->fd >= 0) {
- region->mmap_alias = mmap(NULL, region->mmap_size,
- PROT_READ | PROT_WRITE,
- vm_mem_backing_src_alias(src_type)->flag,
- region->fd, 0);
- TEST_ASSERT(region->mmap_alias != MAP_FAILED,
- __KVM_SYSCALL_ERROR("mmap()", (int)(unsigned long)MAP_FAILED));
+ region->mmap_alias = kvm_mmap(region->mmap_size,
+ PROT_READ | PROT_WRITE,
+ vm_mem_backing_src_alias(src_type)->flag,
+ region->fd);

/* Align host alias address */
region->host_alias = align_ptr_up(region->mmap_alias, alignment);
@@ -1371,10 +1360,8 @@ struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id)
TEST_ASSERT(vcpu_mmap_sz() >= sizeof(*vcpu->run), "vcpu mmap size "
"smaller than expected, vcpu_mmap_sz: %i expected_min: %zi",
vcpu_mmap_sz(), sizeof(*vcpu->run));
- vcpu->run = (struct kvm_run *) mmap(NULL, vcpu_mmap_sz(),
- PROT_READ | PROT_WRITE, MAP_SHARED, vcpu->fd, 0);
- TEST_ASSERT(vcpu->run != MAP_FAILED,
- __KVM_SYSCALL_ERROR("mmap()", (int)(unsigned long)MAP_FAILED));
+ vcpu->run = kvm_mmap(vcpu_mmap_sz(), PROT_READ | PROT_WRITE,
+ MAP_SHARED, vcpu->fd);

if (kvm_has_cap(KVM_CAP_BINARY_STATS_FD))
vcpu->stats.fd = vcpu_get_stats_fd(vcpu);
@@ -1821,9 +1808,8 @@ void *vcpu_map_dirty_ring(struct kvm_vcpu *vcpu)
page_size * KVM_DIRTY_LOG_PAGE_OFFSET);
TEST_ASSERT(addr == MAP_FAILED, "Dirty ring mapped exec");

- addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, vcpu->fd,
- page_size * KVM_DIRTY_LOG_PAGE_OFFSET);
- TEST_ASSERT(addr != MAP_FAILED, "Dirty ring map failed");
+ addr = __kvm_mmap(size, PROT_READ | PROT_WRITE, MAP_SHARED, vcpu->fd,
+ page_size * KVM_DIRTY_LOG_PAGE_OFFSET);

vcpu->dirty_gfns = addr;
vcpu->dirty_gfns_count = size / sizeof(struct kvm_dirty_gfn);
diff --git a/tools/testing/selftests/kvm/mmu_stress_test.c b/tools/testing/selftests/kvm/mmu_stress_test.c
index 6a437d2be9fa..37b7e6524533 100644
--- a/tools/testing/selftests/kvm/mmu_stress_test.c
+++ b/tools/testing/selftests/kvm/mmu_stress_test.c
@@ -339,8 +339,7 @@ int main(int argc, char *argv[])
TEST_ASSERT(max_gpa > (4 * slot_size), "MAXPHYADDR <4gb ");

fd = kvm_memfd_alloc(slot_size, hugepages);
- mem = mmap(NULL, slot_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
- TEST_ASSERT(mem != MAP_FAILED, "mmap() failed");
+ mem = kvm_mmap(slot_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd);

TEST_ASSERT(!madvise(mem, slot_size, MADV_NOHUGEPAGE), "madvise() failed");

@@ -413,7 +412,7 @@ int main(int argc, char *argv[])
for (slot = (slot - 1) & ~1ull; slot >= first_slot; slot -= 2)
vm_set_user_memory_region(vm, slot, 0, 0, 0, NULL);

- munmap(mem, slot_size / 2);
+ kvm_munmap(mem, slot_size / 2);

/* Sanity check that the vCPUs actually ran. */
for (i = 0; i < nr_vcpus; i++)
diff --git a/tools/testing/selftests/kvm/s390/ucontrol_test.c b/tools/testing/selftests/kvm/s390/ucontrol_test.c
index d265b34c54be..50bc1c38225a 100644
--- a/tools/testing/selftests/kvm/s390/ucontrol_test.c
+++ b/tools/testing/selftests/kvm/s390/ucontrol_test.c
@@ -142,19 +142,17 @@ FIXTURE_SETUP(uc_kvm)
self->kvm_run_size = ioctl(self->kvm_fd, KVM_GET_VCPU_MMAP_SIZE, NULL);
ASSERT_GE(self->kvm_run_size, sizeof(struct kvm_run))
TH_LOG(KVM_IOCTL_ERROR(KVM_GET_VCPU_MMAP_SIZE, self->kvm_run_size));
- self->run = (struct kvm_run *)mmap(NULL, self->kvm_run_size,
- PROT_READ | PROT_WRITE, MAP_SHARED, self->vcpu_fd, 0);
- ASSERT_NE(self->run, MAP_FAILED);
+ self->run = kvm_mmap(self->kvm_run_size, PROT_READ | PROT_WRITE,
+ MAP_SHARED, self->vcpu_fd);
/**
* For virtual cpus that have been created with S390 user controlled
* virtual machines, the resulting vcpu fd can be memory mapped at page
* offset KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of
* the virtual cpu's hardware control block.
*/
- self->sie_block = (struct kvm_s390_sie_block *)mmap(NULL, PAGE_SIZE,
- PROT_READ | PROT_WRITE, MAP_SHARED,
- self->vcpu_fd, KVM_S390_SIE_PAGE_OFFSET << PAGE_SHIFT);
- ASSERT_NE(self->sie_block, MAP_FAILED);
+ self->sie_block = __kvm_mmap(PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_SHARED, self->vcpu_fd,
+ KVM_S390_SIE_PAGE_OFFSET << PAGE_SHIFT);

TH_LOG("VM created %p %p", self->run, self->sie_block);

@@ -186,8 +184,8 @@ FIXTURE_SETUP(uc_kvm)

FIXTURE_TEARDOWN(uc_kvm)
{
- munmap(self->sie_block, PAGE_SIZE);
- munmap(self->run, self->kvm_run_size);
+ kvm_munmap(self->sie_block, PAGE_SIZE);
+ kvm_munmap(self->run, self->kvm_run_size);
close(self->vcpu_fd);
close(self->vm_fd);
close(self->kvm_fd);
diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
index ce3ac0fd6dfb..7fe427ff9b38 100644
--- a/tools/testing/selftests/kvm/set_memory_region_test.c
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -433,10 +433,10 @@ static void test_add_max_memory_regions(void)
pr_info("Adding slots 0..%i, each memory region with %dK size\n",
(max_mem_slots - 1), MEM_REGION_SIZE >> 10);

- mem = mmap(NULL, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment,
- PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
- TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
+
+ mem = kvm_mmap((size_t)max_mem_slots * MEM_REGION_SIZE + alignment,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1);
mem_aligned = (void *)(((size_t) mem + alignment - 1) & ~(alignment - 1));

for (slot = 0; slot < max_mem_slots; slot++)
@@ -446,9 +446,8 @@ static void test_add_max_memory_regions(void)
mem_aligned + (uint64_t)slot * MEM_REGION_SIZE);

/* Check it cannot be added memory slots beyond the limit */
- mem_extra = mmap(NULL, MEM_REGION_SIZE, PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
- TEST_ASSERT(mem_extra != MAP_FAILED, "Failed to mmap() host");
+ mem_extra = kvm_mmap(MEM_REGION_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1);

ret = __vm_set_user_memory_region(vm, max_mem_slots, 0,
(uint64_t)max_mem_slots * MEM_REGION_SIZE,
@@ -456,8 +455,8 @@ static void test_add_max_memory_regions(void)
TEST_ASSERT(ret == -1 && errno == EINVAL,
"Adding one more memory slot should fail with EINVAL");

- munmap(mem, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment);
- munmap(mem_extra, MEM_REGION_SIZE);
+ kvm_munmap(mem, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment);
+ kvm_munmap(mem_extra, MEM_REGION_SIZE);
kvm_vm_free(vm);
}

--
2.51.0.536.g15c5d4f767-goog