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, 8 insertions, 23 deletions

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 1a93d6361671..203e33697492 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -704,8 +704,6 @@ userspace_mem_region_find(struct kvm_vm *vm, uint64_t start, uint64_t end)
 
 static void kvm_stats_release(struct kvm_binary_stats *stats)
 {
-	int ret;
-
 	if (stats->fd < 0)
 		return;
 
@@ -714,8 +712,7 @@ static void kvm_stats_release(struct kvm_binary_stats *stats)
 		stats->desc = NULL;
 	}
 
-	ret = close(stats->fd);
-	TEST_ASSERT(!ret,  __KVM_SYSCALL_ERROR("close()", ret));
+	kvm_close(stats->fd);
 	stats->fd = -1;
 }
 
@@ -738,8 +735,6 @@ __weak void vcpu_arch_free(struct kvm_vcpu *vcpu)
  */
 static void vm_vcpu_rm(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
 {
-	int ret;
-
 	if (vcpu->dirty_gfns) {
 		kvm_munmap(vcpu->dirty_gfns, vm->dirty_ring_size);
 		vcpu->dirty_gfns = NULL;
@@ -747,9 +742,7 @@ static void vm_vcpu_rm(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
 
 	kvm_munmap(vcpu->run, vcpu_mmap_sz());
 
-	ret = close(vcpu->fd);
-	TEST_ASSERT(!ret,  __KVM_SYSCALL_ERROR("close()", ret));
-
+	kvm_close(vcpu->fd);
 	kvm_stats_release(&vcpu->stats);
 
 	list_del(&vcpu->list);
@@ -761,16 +754,12 @@ static void vm_vcpu_rm(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
 void kvm_vm_release(struct kvm_vm *vmp)
 {
 	struct kvm_vcpu *vcpu, *tmp;
-	int ret;
 
 	list_for_each_entry_safe(vcpu, tmp, &vmp->vcpus, list)
 		vm_vcpu_rm(vmp, vcpu);
 
-	ret = close(vmp->fd);
-	TEST_ASSERT(!ret,  __KVM_SYSCALL_ERROR("close()", ret));
-
-	ret = close(vmp->kvm_fd);
-	TEST_ASSERT(!ret,  __KVM_SYSCALL_ERROR("close()", ret));
+	kvm_close(vmp->fd);
+	kvm_close(vmp->kvm_fd);
 
 	/* Free cached stats metadata and close FD */
 	kvm_stats_release(&vmp->stats);
@@ -828,7 +817,7 @@ void kvm_vm_free(struct kvm_vm *vmp)
 int kvm_memfd_alloc(size_t size, bool hugepages)
 {
 	int memfd_flags = MFD_CLOEXEC;
-	int fd, r;
+	int fd;
 
 	if (hugepages)
 		memfd_flags |= MFD_HUGETLB;
@@ -836,11 +825,8 @@ int kvm_memfd_alloc(size_t size, bool hugepages)
 	fd = memfd_create("kvm_selftest", memfd_flags);
 	TEST_ASSERT(fd != -1, __KVM_SYSCALL_ERROR("memfd_create()", fd));
 
-	r = ftruncate(fd, size);
-	TEST_ASSERT(!r, __KVM_SYSCALL_ERROR("ftruncate()", r));
-
-	r = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, size);
-	TEST_ASSERT(!r, __KVM_SYSCALL_ERROR("fallocate()", r));
+	kvm_ftruncate(fd, size);
+	kvm_fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, 0, size);
 
 	return fd;
 }
@@ -1084,8 +1070,7 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
 			 * needing to track if the fd is owned by the framework
 			 * or by the caller.
 			 */
-			guest_memfd = dup(guest_memfd);
-			TEST_ASSERT(guest_memfd >= 0, __KVM_SYSCALL_ERROR("dup()", guest_memfd));
+			guest_memfd = kvm_dup(guest_memfd);
 		}
 
 		region->region.guest_memfd = guest_memfd;