KVM: selftests: Remove dynamic memory allocation for stats header

There's no need to allocate dynamic memory for the stats header since
its size is known at compile time.
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-2-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/kvm_binary_stats_test.c

@@ -26,56 +26,53 @@ static void stats_test(int stats_fd)
 	int i;
 	size_t size_desc;
 	size_t size_data = 0;
-	struct kvm_stats_header *header;
+	struct kvm_stats_header header;
 	char *id;
 	struct kvm_stats_desc *stats_desc;
 	u64 *stats_data;
 	struct kvm_stats_desc *pdesc;
 
 	/* Read kvm stats header */
-	header = malloc(sizeof(*header));
-	TEST_ASSERT(header, "Allocate memory for stats header");
-
-	ret = read(stats_fd, header, sizeof(*header));
-	TEST_ASSERT(ret == sizeof(*header), "Read stats header");
-	size_desc = sizeof(*stats_desc) + header->name_size;
+	ret = read(stats_fd, &header, sizeof(header));
+	TEST_ASSERT(ret == sizeof(header), "Read stats header");
+	size_desc = sizeof(*stats_desc) + header.name_size;
 
 	/* Read kvm stats id string */
-	id = malloc(header->name_size);
+	id = malloc(header.name_size);
 	TEST_ASSERT(id, "Allocate memory for id string");
-	ret = read(stats_fd, id, header->name_size);
-	TEST_ASSERT(ret == header->name_size, "Read id string");
+	ret = read(stats_fd, id, header.name_size);
+	TEST_ASSERT(ret == header.name_size, "Read id string");
 
 	/* Check id string, that should start with "kvm" */
-	TEST_ASSERT(!strncmp(id, "kvm", 3) && strlen(id) < header->name_size,
+	TEST_ASSERT(!strncmp(id, "kvm", 3) && strlen(id) < header.name_size,
 				"Invalid KVM stats type, id: %s", id);
 
 	/* Sanity check for other fields in header */
-	if (header->num_desc == 0) {
+	if (header.num_desc == 0) {
 		printf("No KVM stats defined!");
 		return;
 	}
 	/* Check overlap */
-	TEST_ASSERT(header->desc_offset > 0 && header->data_offset > 0
-			&& header->desc_offset >= sizeof(*header)
-			&& header->data_offset >= sizeof(*header),
+	TEST_ASSERT(header.desc_offset > 0 && header.data_offset > 0
+			&& header.desc_offset >= sizeof(header)
+			&& header.data_offset >= sizeof(header),
 			"Invalid offset fields in header");
-	TEST_ASSERT(header->desc_offset > header->data_offset ||
-			(header->desc_offset + size_desc * header->num_desc <=
-							header->data_offset),
+	TEST_ASSERT(header.desc_offset > header.data_offset ||
+			(header.desc_offset + size_desc * header.num_desc <=
+							header.data_offset),
 			"Descriptor block is overlapped with data block");
 
 	/* Allocate memory for stats descriptors */
-	stats_desc = calloc(header->num_desc, size_desc);
+	stats_desc = calloc(header.num_desc, size_desc);
 	TEST_ASSERT(stats_desc, "Allocate memory for stats descriptors");
 	/* Read kvm stats descriptors */
 	ret = pread(stats_fd, stats_desc,
-			size_desc * header->num_desc, header->desc_offset);
-	TEST_ASSERT(ret == size_desc * header->num_desc,
+			size_desc * header.num_desc, header.desc_offset);
+	TEST_ASSERT(ret == size_desc * header.num_desc,
 			"Read KVM stats descriptors");
 
 	/* Sanity check for fields in descriptors */
-	for (i = 0; i < header->num_desc; ++i) {
+	for (i = 0; i < header.num_desc; ++i) {
 		pdesc = (void *)stats_desc + i * size_desc;
 		/* Check type,unit,base boundaries */
 		TEST_ASSERT((pdesc->flags & KVM_STATS_TYPE_MASK)
@@ -104,7 +101,7 @@ static void stats_test(int stats_fd)
 			break;
 		}
 		/* Check name string */
-		TEST_ASSERT(strlen(pdesc->name) < header->name_size,
+		TEST_ASSERT(strlen(pdesc->name) < header.name_size,
 				"KVM stats name(%s) too long", pdesc->name);
 		/* Check size field, which should not be zero */
 		TEST_ASSERT(pdesc->size, "KVM descriptor(%s) with size of 0",
@@ -124,14 +121,14 @@ static void stats_test(int stats_fd)
 		size_data += pdesc->size * sizeof(*stats_data);
 	}
 	/* Check overlap */
-	TEST_ASSERT(header->data_offset >= header->desc_offset
-		|| header->data_offset + size_data <= header->desc_offset,
+	TEST_ASSERT(header.data_offset >= header.desc_offset
+		|| header.data_offset + size_data <= header.desc_offset,
 		"Data block is overlapped with Descriptor block");
 	/* Check validity of all stats data size */
-	TEST_ASSERT(size_data >= header->num_desc * sizeof(*stats_data),
+	TEST_ASSERT(size_data >= header.num_desc * sizeof(*stats_data),
 			"Data size is not correct");
 	/* Check stats offset */
-	for (i = 0; i < header->num_desc; ++i) {
+	for (i = 0; i < header.num_desc; ++i) {
 		pdesc = (void *)stats_desc + i * size_desc;
 		TEST_ASSERT(pdesc->offset < size_data,
 			"Invalid offset (%u) for stats: %s",
@@ -142,15 +139,15 @@ static void stats_test(int stats_fd)
 	stats_data = malloc(size_data);
 	TEST_ASSERT(stats_data, "Allocate memory for stats data");
 	/* Read kvm stats data as a bulk */
-	ret = pread(stats_fd, stats_data, size_data, header->data_offset);
+	ret = pread(stats_fd, stats_data, size_data, header.data_offset);
 	TEST_ASSERT(ret == size_data, "Read KVM stats data");
 	/* Read kvm stats data one by one */
 	size_data = 0;
-	for (i = 0; i < header->num_desc; ++i) {
+	for (i = 0; i < header.num_desc; ++i) {
 		pdesc = (void *)stats_desc + i * size_desc;
 		ret = pread(stats_fd, stats_data,
 				pdesc->size * sizeof(*stats_data),
-				header->data_offset + size_data);
+				header.data_offset + size_data);
 		TEST_ASSERT(ret == pdesc->size * sizeof(*stats_data),
 				"Read data of KVM stats: %s", pdesc->name);
 		size_data += pdesc->size * sizeof(*stats_data);
@@ -159,7 +156,6 @@ static void stats_test(int stats_fd)
 	free(stats_data);
 	free(stats_desc);
 	free(id);
-	free(header);
 }