KVM: selftests: Define wrappers for common syscalls to assert success

Add kvm_<sycall> wrappers for munmap(), close(), fallocate(), and
ftruncate() to cut down on boilerplate code when a sycall is expected
to succeed, and to make it easier for developers to remember to assert
success.

Implement and use a macro framework similar to the kernel's SYSCALL_DEFINE
infrastructure to further cut down on boilerplate code, and to drastically
reduce the probability of typos as the kernel's syscall definitions can be
copy+paste almost verbatim.

Provide macros to build the raw <sycall>() wrappers as well, e.g. to
replace hand-coded wrappers (NUMA) or pure open-coded calls.

Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Shivank Garg <shivankg@amd.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Link: https://lore.kernel.org/r/20251016172853.52451-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 3 insertions, 6 deletions

diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
index 82a8d88b5338..1969f4ab9b28 100644
--- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
+++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
@@ -380,7 +380,7 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, uint32_t
 	struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
 	pthread_t threads[KVM_MAX_VCPUS];
 	struct kvm_vm *vm;
-	int memfd, i, r;
+	int memfd, i;
 
 	const struct vm_shape shape = {
 		.mode = VM_MODE_DEFAULT,
@@ -428,11 +428,8 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, uint32_t
 	 * should prevent the VM from being fully destroyed until the last
 	 * reference to the guest_memfd is also put.
 	 */
-	r = fallocate(memfd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, memfd_size);
-	TEST_ASSERT(!r, __KVM_SYSCALL_ERROR("fallocate()", r));
-
-	r = fallocate(memfd, FALLOC_FL_KEEP_SIZE, 0, memfd_size);
-	TEST_ASSERT(!r, __KVM_SYSCALL_ERROR("fallocate()", r));
+	kvm_fallocate(memfd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, memfd_size);
+	kvm_fallocate(memfd, FALLOC_FL_KEEP_SIZE, 0, memfd_size);
 
 	close(memfd);
 }