[v3,4/4] KVM: selftests: Add selftest for KVM statistics data binary interface

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 34414e83b3f1..a398ddbb84ae 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -42,3 +42,4 @@ 
 /memslot_modification_stress_test
 /set_memory_region_test
 /steal_time
+/kvm_bin_form_stats
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 6b0a9e70083e..567cfef02b76 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -76,6 +76,7 @@  TEST_GEN_PROGS_x86_64 += kvm_page_table_test
 TEST_GEN_PROGS_x86_64 += memslot_modification_stress_test
 TEST_GEN_PROGS_x86_64 += set_memory_region_test
 TEST_GEN_PROGS_x86_64 += steal_time
+TEST_GEN_PROGS_x86_64 += kvm_bin_form_stats
 
 TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
 TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list-sve
@@ -86,6 +87,7 @@  TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus
 TEST_GEN_PROGS_aarch64 += kvm_page_table_test
 TEST_GEN_PROGS_aarch64 += set_memory_region_test
 TEST_GEN_PROGS_aarch64 += steal_time
+TEST_GEN_PROGS_aarch64 += kvm_bin_form_stats
 
 TEST_GEN_PROGS_s390x = s390x/memop
 TEST_GEN_PROGS_s390x += s390x/resets
@@ -95,6 +97,7 @@  TEST_GEN_PROGS_s390x += dirty_log_test
 TEST_GEN_PROGS_s390x += kvm_create_max_vcpus
 TEST_GEN_PROGS_s390x += kvm_page_table_test
 TEST_GEN_PROGS_s390x += set_memory_region_test
+TEST_GEN_PROGS_s390x += kvm_bin_form_stats
 
 TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M))
 LIBKVM += $(LIBKVM_$(UNAME_M))
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 0e6cc25642a6..770b54b5a15c 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -378,4 +378,7 @@  uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);
 #define GUEST_ASSERT_4(_condition, arg1, arg2, arg3, arg4) \
 	__GUEST_ASSERT((_condition), 4, (arg1), (arg2), (arg3), (arg4))
 
+int vm_get_statsfd(struct kvm_vm *vm);
+int vcpu_get_statsfd(struct kvm_vm *vm, uint32_t vcpuid);
+
 #endif /* SELFTEST_KVM_UTIL_H */
diff --git a/tools/testing/selftests/kvm/kvm_bin_form_stats.c b/tools/testing/selftests/kvm/kvm_bin_form_stats.c
new file mode 100644
index 000000000000..44dd6341dcaf
--- /dev/null
+++ b/tools/testing/selftests/kvm/kvm_bin_form_stats.c
@@ -0,0 +1,370 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kvm_bin_form_stats
+ *
+ * Copyright (C) 2021, Google LLC.
+ *
+ * Test the fd-based interface for KVM statistics.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "asm/kvm.h"
+#include "linux/kvm.h"
+
+int vm_stats_test(struct kvm_vm *vm)
+{
+	ssize_t ret;
+	int i, stats_fd, err = -1;
+	size_t size_desc, size_data = 0;
+	struct kvm_stats_header header;
+	struct kvm_stats_desc *stats_desc, *pdesc;
+	struct kvm_vm_stats_data *stats_data;
+
+	/* Get fd for VM stats */
+	stats_fd = vm_get_statsfd(vm);
+	if (stats_fd < 0) {
+		perror("Get VM stats fd");
+		return err;
+	}
+	/* Read kvm vm stats header */
+	ret = read(stats_fd, &header, sizeof(header));
+	if (ret != sizeof(header)) {
+		perror("Read VM stats header");
+		goto out_close_fd;
+	}
+	size_desc = sizeof(*stats_desc) + header.name_size;
+	/* Check id string in header, that should start with "kvm" */
+	if (strncmp(header.id, "kvm", 3) ||
+			strlen(header.id) >= KVM_STATS_ID_MAXLEN) {
+		printf("Invalid KVM VM stats type!\n");
+		goto out_close_fd;
+	}
+	/* Sanity check for other fields in header */
+	if (header.count == 0) {
+		err = 0;
+		goto out_close_fd;
+	}
+	/* Check overlap */
+	if (header.desc_offset == 0 || header.data_offset == 0 ||
+			header.desc_offset < sizeof(header) ||
+			header.data_offset < sizeof(header)) {
+		printf("Invalid offset fields in header!\n");
+		goto out_close_fd;
+	}
+	if (header.desc_offset < header.data_offset &&
+			(header.desc_offset + size_desc * header.count >
+			header.data_offset)) {
+		printf("Descriptor block is overlapped with data block!\n");
+		goto out_close_fd;
+	}
+
+	/* Allocate memory for stats descriptors */
+	stats_desc = calloc(header.count, size_desc);
+	if (!stats_desc) {
+		perror("Allocate memory for VM stats descriptors");
+		goto out_close_fd;
+	}
+	/* Read kvm vm stats descriptors */
+	ret = pread(stats_fd, stats_desc,
+			size_desc * header.count, header.desc_offset);
+	if (ret != size_desc * header.count) {
+		perror("Read KVM VM stats descriptors");
+		goto out_free_desc;
+	}
+	/* Sanity check for fields in descriptors */
+	for (i = 0; i < header.count; ++i) {
+		pdesc = (void *)stats_desc + i * size_desc;
+		/* Check type,unit,scale boundaries */
+		if ((pdesc->flags & KVM_STATS_TYPE_MASK) > KVM_STATS_TYPE_MAX) {
+			printf("Unknown KVM stats type!\n");
+			goto out_free_desc;
+		}
+		if ((pdesc->flags & KVM_STATS_UNIT_MASK) > KVM_STATS_UNIT_MAX) {
+			printf("Unknown KVM stats unit!\n");
+			goto out_free_desc;
+		}
+		if ((pdesc->flags & KVM_STATS_SCALE_MASK) >
+				KVM_STATS_SCALE_MAX) {
+			printf("Unknown KVM stats scale!\n");
+			goto out_free_desc;
+		}
+		/* Check exponent for stats unit
+		 * Exponent for counter should be greater than or equal to 0
+		 * Exponent for unit bytes should be greater than or equal to 0
+		 * Exponent for unit seconds should be less than or equal to 0
+		 * Exponent for unit clock cycles should be greater than or
+		 * equal to 0
+		 */
+		switch (pdesc->flags & KVM_STATS_UNIT_MASK) {
+		case KVM_STATS_UNIT_NONE:
+		case KVM_STATS_UNIT_BYTES:
+		case KVM_STATS_UNIT_CYCLES:
+			if (pdesc->exponent < 0) {
+				printf("Unsupported KVM stats unit!\n");
+				goto out_free_desc;
+			}
+			break;
+		case KVM_STATS_UNIT_SECONDS:
+			if (pdesc->exponent > 0) {
+				printf("Unsupported KVM stats unit!\n");
+				goto out_free_desc;
+			}
+			break;
+		}
+		/* Check name string */
+		if (strlen(pdesc->name) >= header.name_size) {
+			printf("KVM stats name(%s) too long!\n", pdesc->name);
+			goto out_free_desc;
+		}
+		/* Check size field, which should not be zero */
+		if (pdesc->size == 0) {
+			printf("KVM descriptor(%s) with size of 0!\n",
+					pdesc->name);
+			goto out_free_desc;
+		}
+		size_data = pdesc->size * sizeof(stats_data->value[0]);
+	}
+	/* Check overlap */
+	if (header.data_offset < header.desc_offset &&
+		header.data_offset + size_data > header.desc_offset) {
+		printf("Data block is overlapped with Descriptor block!\n");
+		goto out_free_desc;
+	}
+
+	/* Allocate memory for stats data */
+	stats_data = malloc(size_data);
+	if (!stats_data) {
+		perror("Allocate memory for VM stats data");
+		goto out_free_desc;
+	}
+	/* Read kvm vm stats data */
+	ret = pread(stats_fd, stats_data, size_data, header.data_offset);
+	if (ret != size_data) {
+		perror("Read KVM VM stats data");
+		goto out_free_data;
+	}
+
+	err = 0;
+out_free_data:
+	free(stats_data);
+out_free_desc:
+	free(stats_desc);
+out_close_fd:
+	close(stats_fd);
+	return err;
+}
+
+int vcpu_stats_test(struct kvm_vm *vm, int vcpu_id)
+{
+	ssize_t ret;
+	int i, stats_fd, err = -1;
+	size_t size_desc, size_data = 0;
+	struct kvm_stats_header header;
+	struct kvm_stats_desc *stats_desc, *pdesc;
+	struct kvm_vcpu_stats_data *stats_data;
+
+	/* Get fd for VCPU stats */
+	stats_fd = vcpu_get_statsfd(vm, vcpu_id);
+	if (stats_fd < 0) {
+		perror("Get VCPU stats fd");
+		return err;
+	}
+	/* Read kvm vcpu stats header */
+	ret = read(stats_fd, &header, sizeof(header));
+	if (ret != sizeof(header)) {
+		perror("Read VCPU stats header");
+		goto out_close_fd;
+	}
+	size_desc = sizeof(*stats_desc) + header.name_size;
+	/* Check id string in header, that should start with "kvm" */
+	if (strncmp(header.id, "kvm", 3) ||
+			strlen(header.id) >= KVM_STATS_ID_MAXLEN) {
+		printf("Invalid KVM VCPU stats type!\n");
+		goto out_close_fd;
+	}
+	/* Sanity check for other fields in header */
+	if (header.count == 0) {
+		err = 0;
+		goto out_close_fd;
+	}
+	/* Check overlap */
+	if (header.desc_offset == 0 || header.data_offset == 0 ||
+			header.desc_offset < sizeof(header) ||
+			header.data_offset < sizeof(header)) {
+		printf("Invalid offset fields in header!\n");
+		goto out_close_fd;
+	}
+	if (header.desc_offset < header.data_offset &&
+			(header.desc_offset + size_desc * header.count >
+			header.data_offset)) {
+		printf("Descriptor block is overlapped with data block!\n");
+		goto out_close_fd;
+	}
+
+	/* Allocate memory for stats descriptors */
+	stats_desc = calloc(header.count, size_desc);
+	if (!stats_desc) {
+		perror("Allocate memory for VCPU stats descriptors");
+		goto out_close_fd;
+	}
+	/* Read kvm vcpu stats descriptors */
+	ret = pread(stats_fd, stats_desc,
+			size_desc * header.count, header.desc_offset);
+	if (ret != size_desc * header.count) {
+		perror("Read KVM VCPU stats descriptors");
+		goto out_free_desc;
+	}
+	/* Sanity check for fields in descriptors */
+	for (i = 0; i < header.count; ++i) {
+		pdesc = (void *)stats_desc + i * size_desc;
+		/* Check boundaries */
+		if ((pdesc->flags & KVM_STATS_TYPE_MASK) > KVM_STATS_TYPE_MAX) {
+			printf("Unknown KVM stats type!\n");
+			goto out_free_desc;
+		}
+		if ((pdesc->flags & KVM_STATS_UNIT_MASK) > KVM_STATS_UNIT_MAX) {
+			printf("Unknown KVM stats unit!\n");
+			goto out_free_desc;
+		}
+		if ((pdesc->flags & KVM_STATS_SCALE_MASK) >
+				KVM_STATS_SCALE_MAX) {
+			printf("Unknown KVM stats scale!\n");
+			goto out_free_desc;
+		}
+		/* Check exponent for stats unit
+		 * Exponent for counter should be greater than or equal to 0
+		 * Exponent for unit bytes should be greater than or equal to 0
+		 * Exponent for unit seconds should be less than or equal to 0
+		 * Exponent for unit clock cycles should be greater than or
+		 * equal to 0
+		 */
+		switch (pdesc->flags & KVM_STATS_UNIT_MASK) {
+		case KVM_STATS_UNIT_NONE:
+		case KVM_STATS_UNIT_BYTES:
+		case KVM_STATS_UNIT_CYCLES:
+			if (pdesc->exponent < 0) {
+				printf("Unsupported KVM stats unit!\n");
+				goto out_free_desc;
+			}
+			break;
+		case KVM_STATS_UNIT_SECONDS:
+			if (pdesc->exponent > 0) {
+				printf("Unsupported KVM stats unit!\n");
+				goto out_free_desc;
+			}
+			break;
+		}
+		/* Check name string */
+		if (strlen(pdesc->name) >= header.name_size) {
+			printf("KVM stats name(%s) too long!\n", pdesc->name);
+			goto out_free_desc;
+		}
+		/* Check size field, which should not be zero */
+		if (pdesc->size == 0) {
+			printf("KVM descriptor(%s) with size of 0!\n",
+					pdesc->name);
+			goto out_free_desc;
+		}
+		size_data = pdesc->size * sizeof(stats_data->value[0]);
+	}
+	/* Check overlap */
+	if (header.data_offset < header.desc_offset &&
+		header.data_offset + size_data > header.desc_offset) {
+		printf("Data block is overlapped with Descriptor block!\n");
+		goto out_free_desc;
+	}
+
+	/* Allocate memory for stats data */
+	stats_data = malloc(size_data);
+	if (!stats_data) {
+		perror("Allocate memory for VCPU stats data");
+		goto out_free_desc;
+	}
+	/* Read kvm vcpu stats data */
+	ret = pread(stats_fd, stats_data, size_data, header.data_offset);
+	if (ret != size_data) {
+		perror("Read KVM VCPU stats data");
+		goto out_free_data;
+	}
+
+	err = 0;
+out_free_data:
+	free(stats_data);
+out_free_desc:
+	free(stats_desc);
+out_close_fd:
+	close(stats_fd);
+	return err;
+}
+
+/*
+ * Usage: kvm_bin_form_stats [#vm] [#vcpu]
+ * The first parameter #vm set the number of VMs being created.
+ * The second parameter #vcpu set the number of VCPUs being created.
+ * By default, 1 VM and 1 VCPU for the VM would be created for testing.
+ */
+
+int main(int argc, char *argv[])
+{
+	int max_vm = 1, max_vcpu = 1, ret, i, j, err = -1;
+	struct kvm_vm **vms;
+
+	/* Get the number of VMs and VCPUs that would be created for testing. */
+	if (argc > 1) {
+		max_vm = strtol(argv[1], NULL, 0);
+		if (max_vm <= 0)
+			max_vm = 1;
+	}
+	if (argc > 2 ) {
+		max_vcpu = strtol(argv[2], NULL, 0);
+		if (max_vcpu <= 0)
+			max_vcpu = 1;
+	}
+
+	/* Check the extension for binary stats */
+	ret = kvm_check_cap(KVM_CAP_STATS_BINARY_FD);
+	if (ret < 0) {
+		printf("Binary form statistics interface is not supported!\n");
+		return err;
+	}
+
+	/* Create VMs and VCPUs */
+	vms = malloc(sizeof(vms[0]) * max_vm);
+	if (!vms) {
+		perror("Allocate memory for storing VM pointers");
+		return err;
+	}
+	for (i = 0; i < max_vm; ++i) {
+		vms[i] = vm_create(VM_MODE_DEFAULT,
+				DEFAULT_GUEST_PHY_PAGES, O_RDWR);
+		for (j = 0; j < max_vcpu; ++j) {
+			vm_vcpu_add(vms[i], j);
+		}
+	}
+
+	/* Check stats read for every VM and VCPU */
+	for (i = 0; i < max_vm; ++i) {
+		if (vm_stats_test(vms[i]))
+			goto out_free_vm;
+		for (j = 0; j < max_vcpu; ++j) {
+			if (vcpu_stats_test(vms[i], j))
+				goto out_free_vm;
+		}
+	}
+
+	err = 0;
+out_free_vm:
+	for (i = 0; i < max_vm; ++i)
+		kvm_vm_free(vms[i]);
+	free(vms);
+	return err;
+}
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 35247dba362e..bc2ad96b7a86 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -2015,3 +2015,14 @@  unsigned int vm_calc_num_guest_pages(enum vm_guest_mode mode, size_t size)
 	n = DIV_ROUND_UP(size, vm_guest_mode_params[mode].page_size);
 	return vm_adjust_num_guest_pages(mode, n);
 }
+
+int vm_get_statsfd(struct kvm_vm *vm)
+{
+	return ioctl(vm->fd, KVM_STATS_GETFD, NULL);
+}
+
+int vcpu_get_statsfd(struct kvm_vm *vm, uint32_t vcpuid)
+{
+	struct vcpu *vcpu = vcpu_find(vm, vcpuid);
+	return ioctl(vcpu->fd, KVM_STATS_GETFD, NULL);
+}