vfio: selftests: Add allocation assert helpers

Add {malloc,calloc}_assert() helpers alongside the existing *_assert()
helpers.

Use them for VFIO selftest allocations that immediately assert a
non-NULL result.

Assisted-by: Codex:gpt-5.5-high
Signed-off-by: Alex Mastro <amastro@fb.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20260617-scratch-amastro-vfio-selftests-avoid-vlas-v4-1-b9f52f1e2c5a@fb.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

tools/testing/selftests/vfio/lib/include/libvfio/assert.h

@@ -3,6 +3,7 @@
 #define SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_ASSERT_H
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>
 
@@ -45,6 +46,23 @@
 	VFIO_LOG_AND_EXIT(_fmt, ##__VA_ARGS__);			\
 } while (0)
 
+#define malloc_assert(_size) ({					\
+	size_t __size = (_size);				\
+	void *__ptr = malloc(__size);				\
+	VFIO_ASSERT_NOT_NULL(__ptr, "malloc(%zu) failed",	\
+			     __size);				\
+	__ptr;							\
+})
+
+#define calloc_assert(_nmemb, _size) ({				\
+	size_t __nmemb = (_nmemb);				\
+	size_t __size = (_size);				\
+	void *__ptr = calloc(__nmemb, __size);			\
+	VFIO_ASSERT_NOT_NULL(__ptr, "calloc(%zu, %zu) failed",	\
+			     __nmemb, __size);			\
+	__ptr;							\
+})
+
 #define ioctl_assert(_fd, _op, _arg) do {						       \
 	void *__arg = (_arg);								       \
 	int __ret = ioctl((_fd), (_op), (__arg));					       \

tools/testing/selftests/vfio/lib/iommu.c

@@ -286,8 +286,7 @@ static struct vfio_iommu_type1_info *vfio_iommu_get_info(int container_fd)
 {
 	struct vfio_iommu_type1_info *info;
 
-	info = malloc(sizeof(*info));
-	VFIO_ASSERT_NOT_NULL(info);
+	info = malloc_assert(sizeof(*info));
 
 	*info = (struct vfio_iommu_type1_info) {
 		.argsz = sizeof(*info),
@@ -324,8 +323,7 @@ static struct iommu_iova_range *vfio_iommu_iova_ranges(struct iommu *iommu,
 	cap_range = container_of(hdr, struct vfio_iommu_type1_info_cap_iova_range, header);
 	VFIO_ASSERT_GT(cap_range->nr_iovas, 0);
 
-	ranges = calloc(cap_range->nr_iovas, sizeof(*ranges));
-	VFIO_ASSERT_NOT_NULL(ranges);
+	ranges = calloc_assert(cap_range->nr_iovas, sizeof(*ranges));
 
 	for (u32 i = 0; i < cap_range->nr_iovas; i++) {
 		ranges[i] = (struct iommu_iova_range){
@@ -357,8 +355,7 @@ static struct iommu_iova_range *iommufd_iova_ranges(struct iommu *iommu,
 	VFIO_ASSERT_EQ(errno, EMSGSIZE);
 	VFIO_ASSERT_GT(query.num_iovas, 0);
 
-	ranges = calloc(query.num_iovas, sizeof(*ranges));
-	VFIO_ASSERT_NOT_NULL(ranges);
+	ranges = calloc_assert(query.num_iovas, sizeof(*ranges));
 
 	query.allowed_iovas = (uintptr_t)ranges;
 
@@ -424,8 +421,7 @@ struct iommu *iommu_init(const char *iommu_mode)
 	struct iommu *iommu;
 	int version;
 
-	iommu = calloc(1, sizeof(*iommu));
-	VFIO_ASSERT_NOT_NULL(iommu);
+	iommu = calloc_assert(1, sizeof(*iommu));
 
 	INIT_LIST_HEAD(&iommu->dma_regions);
 

tools/testing/selftests/vfio/lib/iova_allocator.c

@@ -29,8 +29,7 @@ struct iova_allocator *iova_allocator_init(struct iommu *iommu)
 	ranges = iommu_iova_ranges(iommu, &nranges);
 	VFIO_ASSERT_NOT_NULL(ranges);
 
-	allocator = malloc(sizeof(*allocator));
-	VFIO_ASSERT_NOT_NULL(allocator);
+	allocator = malloc_assert(sizeof(*allocator));
 
 	*allocator = (struct iova_allocator){
 		.ranges = ranges,
@@ -90,4 +89,3 @@ iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size)
 		allocator->range_offset = 0;
 	}
 }
-

tools/testing/selftests/vfio/lib/sysfs.c

@@ -107,8 +107,7 @@ char *sysfs_sriov_vf_bdf_get(const char *pf_bdf, int i)
 	char *out_vf_bdf;
 
 	/* Fit "0000:00:00.0" */
-	out_vf_bdf = calloc(16, sizeof(char));
-	VFIO_ASSERT_NOT_NULL(out_vf_bdf);
+	out_vf_bdf = calloc_assert(16, sizeof(char));
 
 	snprintf_assert(path, PATH_MAX, "/sys/bus/pci/devices/%s/virtfn%d", pf_bdf, i);
 	readlink_base(path, "%s", out_vf_bdf);

tools/testing/selftests/vfio/lib/vfio_pci_device.c

@@ -343,8 +343,7 @@ const char *vfio_pci_get_cdev_path(const char *bdf)
 	char *cdev_path;
 	DIR *dir;
 
-	cdev_path = calloc(PATH_MAX, 1);
-	VFIO_ASSERT_NOT_NULL(cdev_path);
+	cdev_path = calloc_assert(PATH_MAX, 1);
 
 	snprintf_assert(dir_path, sizeof(dir_path), "/sys/bus/pci/devices/%s/vfio-dev/", bdf);
 
@@ -425,8 +424,7 @@ struct vfio_pci_device *vfio_pci_device_alloc(const char *bdf, struct iommu *iom
 {
 	struct vfio_pci_device *device;
 
-	device = calloc(1, sizeof(*device));
-	VFIO_ASSERT_NOT_NULL(device);
+	device = calloc_assert(1, sizeof(*device));
 
 	VFIO_ASSERT_NOT_NULL(iommu);
 	device->iommu = iommu;

tools/testing/selftests/vfio/vfio_pci_device_init_perf_test.c

@@ -45,8 +45,8 @@ FIXTURE_SETUP(vfio_pci_device_init_perf_test)
 	int i;
 
 	self->iommu = iommu_init(variant->iommu_mode);
-	self->threads = calloc(nr_devices, sizeof(self->threads[0]));
-	self->thread_args = calloc(nr_devices, sizeof(self->thread_args[0]));
+	self->threads = calloc_assert(nr_devices, sizeof(self->threads[0]));
+	self->thread_args = calloc_assert(nr_devices, sizeof(self->thread_args[0]));
 
 	pthread_barrier_init(&self->barrier, NULL, nr_devices);