[PATCH v2 1/4] selftests: KVM: Dump VM stats in binary stats test

[Mingwei Zhang <mizhang@google.com>]

From: Ben Gardon <bgardon@google.com>

Add kvm_util library functions to read KVM stats through the binary
stats interface and then dump them to stdout when running the binary
stats test. Subsequent commits will extend the kvm_util code and use it
to make assertions in a test for NX hugepages.

CC: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
---
 .../selftests/kvm/include/kvm_util_base.h     |   1 +
 .../selftests/kvm/kvm_binary_stats_test.c     |   3 +
 tools/testing/selftests/kvm/lib/kvm_util.c    | 143 ++++++++++++++++++
 3 files changed, 147 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 4ed6aa049a91..160b9ad8474a 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -392,6 +392,7 @@ void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid);
 
 int vm_get_stats_fd(struct kvm_vm *vm);
 int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid);
+void dump_vm_stats(struct kvm_vm *vm);
 
 uint32_t guest_get_vcpuid(void);
 
diff --git a/tools/testing/selftests/kvm/kvm_binary_stats_test.c b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
index 17f65d514915..afc4701ce8dd 100644
--- a/tools/testing/selftests/kvm/kvm_binary_stats_test.c
+++ b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
@@ -174,6 +174,9 @@ static void vm_stats_test(struct kvm_vm *vm)
 	stats_test(stats_fd);
 	close(stats_fd);
 	TEST_ASSERT(fcntl(stats_fd, F_GETFD) == -1, "Stats fd not freed");
+
+	/* Dump VM stats */
+	dump_vm_stats(vm);
 }
 
 static void vcpu_stats_test(struct kvm_vm *vm, int vcpu_id)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index d8cf851ab119..d9c660913403 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -2517,3 +2517,146 @@ int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid)
 
 	return ioctl(vcpu->fd, KVM_GET_STATS_FD, NULL);
 }
+
+/* Caller is responsible for freeing the returned kvm_stats_header. */
+static struct kvm_stats_header *read_vm_stats_header(int stats_fd)
+{
+	struct kvm_stats_header *header;
+	ssize_t ret;
+
+	/* 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");
+
+	return header;
+}
+
+static void dump_header(int stats_fd, struct kvm_stats_header *header)
+{
+	ssize_t ret;
+	char *id;
+
+	printf("flags: %u\n", header->flags);
+	printf("name size: %u\n", header->name_size);
+	printf("num_desc: %u\n", header->num_desc);
+	printf("id_offset: %u\n", header->id_offset);
+	printf("desc_offset: %u\n", header->desc_offset);
+	printf("data_offset: %u\n", header->data_offset);
+
+	/* Read kvm stats id string */
+	id = malloc(header->name_size);
+	TEST_ASSERT(id, "Allocate memory for id string");
+	ret = pread(stats_fd, id, header->name_size, header->id_offset);
+	TEST_ASSERT(ret == header->name_size, "Read id string");
+
+	printf("id: %s\n", id);
+
+	free(id);
+}
+
+static ssize_t stats_desc_size(struct kvm_stats_header *header)
+{
+	return sizeof(struct kvm_stats_desc) + header->name_size;
+}
+
+/* Caller is responsible for freeing the returned kvm_stats_desc. */
+static struct kvm_stats_desc *read_vm_stats_desc(int stats_fd,
+						 struct kvm_stats_header *header)
+{
+	struct kvm_stats_desc *stats_desc;
+	size_t size_desc;
+	ssize_t ret;
+
+	size_desc = header->num_desc * stats_desc_size(header);
+
+	/* Allocate memory for stats descriptors */
+	stats_desc = malloc(size_desc);
+	TEST_ASSERT(stats_desc, "Allocate memory for stats descriptors");
+
+	/* Read kvm stats descriptors */
+	ret = pread(stats_fd, stats_desc, size_desc, header->desc_offset);
+	TEST_ASSERT(ret == size_desc, "Read KVM stats descriptors");
+
+	return stats_desc;
+}
+
+/* Caller is responsible for freeing the memory *data. */
+static int read_stat_data(int stats_fd, struct kvm_stats_header *header,
+			  struct kvm_stats_desc *desc, uint64_t **data)
+{
+	u64 *stats_data;
+	ssize_t ret;
+
+	stats_data = malloc(desc->size * sizeof(*stats_data));
+
+	ret = pread(stats_fd, stats_data, desc->size * sizeof(*stats_data),
+		    header->data_offset + desc->offset);
+
+	/* ret is in bytes. */
+	ret = ret / sizeof(*stats_data);
+
+	TEST_ASSERT(ret == desc->size,
+		    "Read data of KVM stats: %s", desc->name);
+
+	*data = stats_data;
+
+	return ret;
+}
+
+static void dump_stat(int stats_fd, struct kvm_stats_header *header,
+		      struct kvm_stats_desc *desc)
+{
+	u64 *stats_data;
+	ssize_t ret;
+	int i;
+
+	printf("\tflags: %u\n", desc->flags);
+	printf("\texponent: %u\n", desc->exponent);
+	printf("\tsize: %u\n", desc->size);
+	printf("\toffset: %u\n", desc->offset);
+	printf("\tbucket_size: %u\n", desc->bucket_size);
+	printf("\tname: %s\n", (char *)&desc->name);
+
+	ret = read_stat_data(stats_fd, header, desc, &stats_data);
+
+	printf("\tdata: %lu", *stats_data);
+	for (i = 1; i < ret; i++)
+		printf(", %lu", *(stats_data + i));
+	printf("\n\n");
+
+	free(stats_data);
+}
+
+void dump_vm_stats(struct kvm_vm *vm)
+{
+	struct kvm_stats_desc *stats_desc;
+	struct kvm_stats_header *header;
+	struct kvm_stats_desc *desc;
+	size_t size_desc;
+	int stats_fd;
+	int i;
+
+	stats_fd = vm_get_stats_fd(vm);
+
+	header = read_vm_stats_header(stats_fd);
+	dump_header(stats_fd, header);
+
+	stats_desc = read_vm_stats_desc(stats_fd, header);
+
+	size_desc = stats_desc_size(header);
+
+	/* Read kvm stats data one by one */
+	for (i = 0; i < header->num_desc; ++i) {
+		desc = (void *)stats_desc + (i * size_desc);
+		dump_stat(stats_fd, header, desc);
+	}
+
+	free(stats_desc);
+	free(header);
+
+	close(stats_fd);
+}
+
-- 
2.35.1.1021.g381101b075-goog