KVM: selftests: Add selftest for KVM statistics data binary interface

Add selftest to check KVM stats descriptors validity.
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Tested-by: Fuad Tabba <tabba@google.com> #arm64
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Message-Id: <20210618222709.1858088-7-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/.gitignore

@@ -47,3 +47,4 @@
 /memslot_perf_test
 /set_memory_region_test
 /steal_time
+/kvm_binary_stats_test

tools/testing/selftests/kvm/Makefile

@@ -80,6 +80,7 @@ TEST_GEN_PROGS_x86_64 += memslot_modification_stress_test
 TEST_GEN_PROGS_x86_64 += memslot_perf_test
 TEST_GEN_PROGS_x86_64 += set_memory_region_test
 TEST_GEN_PROGS_x86_64 += steal_time
+TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test
 
 TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
 TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list-sve
@@ -91,6 +92,7 @@ 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_binary_stats_test
 
 TEST_GEN_PROGS_s390x = s390x/memop
 TEST_GEN_PROGS_s390x += s390x/resets
@@ -100,6 +102,7 @@ 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_binary_stats_test
 
 TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M))
 LIBKVM += $(LIBKVM_$(UNAME_M))

tools/testing/selftests/kvm/include/kvm_util.h

@@ -393,4 +393,7 @@ 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_stats_fd(struct kvm_vm *vm);
+int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid);
+
 #endif /* SELFTEST_KVM_UTIL_H */

tools/testing/selftests/kvm/kvm_binary_stats_test.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kvm_binary_stats_test
+ *
+ * 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"
+
+static void stats_test(int stats_fd)
+{
+	ssize_t ret;
+	int i;
+	size_t size_desc;
+	size_t size_data = 0;
+	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;
+
+	/* Read kvm stats id string */
+	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");
+
+	/* Check id string, that should start with "kvm" */
+	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) {
+		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),
+			"Invalid offset fields in header");
+	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);
+	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,
+			"Read KVM stats descriptors");
+
+	/* Sanity check for fields in descriptors */
+	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)
+				<= KVM_STATS_TYPE_MAX, "Unknown KVM stats type");
+		TEST_ASSERT((pdesc->flags & KVM_STATS_UNIT_MASK)
+				<= KVM_STATS_UNIT_MAX, "Unknown KVM stats unit");
+		TEST_ASSERT((pdesc->flags & KVM_STATS_BASE_MASK)
+				<= KVM_STATS_BASE_MAX, "Unknown KVM stats base");
+		/* 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:
+			TEST_ASSERT(pdesc->exponent >= 0,
+					"Unsupported KVM stats unit");
+			break;
+		case KVM_STATS_UNIT_SECONDS:
+			TEST_ASSERT(pdesc->exponent <= 0,
+					"Unsupported KVM stats unit");
+			break;
+		}
+		/* Check name string */
+		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",
+				pdesc->name);
+		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,
+		"Data block is overlapped with Descriptor block");
+	/* Check validity of all stats data size */
+	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) {
+		pdesc = (void *)stats_desc + i * size_desc;
+		TEST_ASSERT(pdesc->offset < size_data,
+			"Invalid offset (%u) for stats: %s",
+			pdesc->offset, pdesc->name);
+	}
+
+	/* Allocate memory for stats data */
+	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);
+	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) {
+		pdesc = (void *)stats_desc + i * size_desc;
+		ret = pread(stats_fd, stats_data,
+				pdesc->size * sizeof(*stats_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);
+	}
+
+	free(stats_data);
+	free(stats_desc);
+	free(id);
+	free(header);
+}
+
+
+static void vm_stats_test(struct kvm_vm *vm)
+{
+	int stats_fd;
+
+	/* Get fd for VM stats */
+	stats_fd = vm_get_stats_fd(vm);
+	TEST_ASSERT(stats_fd >= 0, "Get VM stats fd");
+
+	stats_test(stats_fd);
+	close(stats_fd);
+	TEST_ASSERT(fcntl(stats_fd, F_GETFD) == -1, "Stats fd not freed");
+}
+
+static void vcpu_stats_test(struct kvm_vm *vm, int vcpu_id)
+{
+	int stats_fd;
+
+	/* Get fd for VCPU stats */
+	stats_fd = vcpu_get_stats_fd(vm, vcpu_id);
+	TEST_ASSERT(stats_fd >= 0, "Get VCPU stats fd");
+
+	stats_test(stats_fd);
+	close(stats_fd);
+	TEST_ASSERT(fcntl(stats_fd, F_GETFD) == -1, "Stats fd not freed");
+}
+
+#define DEFAULT_NUM_VM		4
+#define DEFAULT_NUM_VCPU	4
+
+/*
+ * 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, DEFAULT_NUM_VM VM and DEFAULT_NUM_VCPU VCPU for the VM would be
+ * created for testing.
+ */
+
+int main(int argc, char *argv[])
+{
+	int i, j;
+	struct kvm_vm **vms;
+	int max_vm = DEFAULT_NUM_VM;
+	int max_vcpu = DEFAULT_NUM_VCPU;
+
+	/* 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 = DEFAULT_NUM_VM;
+	}
+	if (argc > 2) {
+		max_vcpu = strtol(argv[2], NULL, 0);
+		if (max_vcpu <= 0)
+			max_vcpu = DEFAULT_NUM_VCPU;
+	}
+
+	/* Check the extension for binary stats */
+	if (kvm_check_cap(KVM_CAP_BINARY_STATS_FD) <= 0) {
+		print_skip("Binary form statistics interface is not supported");
+		exit(KSFT_SKIP);
+	}
+
+	/* Create VMs and VCPUs */
+	vms = malloc(sizeof(vms[0]) * max_vm);
+	TEST_ASSERT(vms, "Allocate memory for storing VM pointers");
+	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) {
+		vm_stats_test(vms[i]);
+		for (j = 0; j < max_vcpu; ++j)
+			vcpu_stats_test(vms[i], j);
+	}
+
+	for (i = 0; i < max_vm; ++i)
+		kvm_vm_free(vms[i]);
+	free(vms);
+	return 0;
+}

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -2326,3 +2326,15 @@ 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_stats_fd(struct kvm_vm *vm)
+{
+	return ioctl(vm->fd, KVM_GET_STATS_FD, NULL);
+}
+
+int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid)
+{
+	struct vcpu *vcpu = vcpu_find(vm, vcpuid);
+
+	return ioctl(vcpu->fd, KVM_GET_STATS_FD, NULL);
+}