// SPDX-License-Identifier: GPL-2.0-only
/*
 * kvm_binary_stats_test
 *
 * Copyright (C) 2021, Google LLC.
 *
 * Test the fd-based interface for KVM statistics.
 */
#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"
#include "kselftest.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;
        u32 type, unit, base;

        /* Read kvm stats header */
        read_stats_header(stats_fd, &header);

        size_desc = get_stats_descriptor_size(&header);

        /* 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, sizeof(header));
        TEST_ASSERT(ret == header.name_size,
                    "Expected header size '%u', read '%lu' bytes",
                    header.name_size, ret);

        /* 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) {
                ksft_print_msg("No KVM stats defined!\n");
                return;
        }
        /*
         * The descriptor and data offsets must be valid, they must not overlap
         * the header, and the descriptor and data blocks must not overlap each
         * other.  Note, the data block is rechecked after its size is known.
         */
        TEST_ASSERT(header.desc_offset && header.desc_offset >= sizeof(header) &&
                    header.data_offset && 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");

        /* Read kvm stats descriptors */
        stats_desc = read_stats_descriptors(stats_fd, &header);

        /* Sanity check for fields in descriptors */
        for (i = 0; i < header.num_desc; ++i) {
                pdesc = get_stats_descriptor(stats_desc, i, &header);
                type = pdesc->flags & KVM_STATS_TYPE_MASK;
                unit = pdesc->flags & KVM_STATS_UNIT_MASK;
                base = pdesc->flags & KVM_STATS_BASE_MASK;

                /* Check name string */
                TEST_ASSERT(strlen(pdesc->name) < header.name_size,
                            "KVM stats name (index: %d) too long", i);

                /* Check type,unit,base boundaries */
                TEST_ASSERT(type <= KVM_STATS_TYPE_MAX,
                            "Unknown KVM stats (%s) type: %u", pdesc->name, type);
                TEST_ASSERT(unit <= KVM_STATS_UNIT_MAX,
                            "Unknown KVM stats (%s) unit: %u", pdesc->name, unit);
                TEST_ASSERT(base <= KVM_STATS_BASE_MAX,
                            "Unknown KVM stats (%s) base: %u", pdesc->name, 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
                 * Exponent for unit boolean should be 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 (%s) exponent: %i",
                                    pdesc->name, pdesc->exponent);
                        break;
                case KVM_STATS_UNIT_SECONDS:
                        TEST_ASSERT(pdesc->exponent <= 0,
                                    "Unsupported KVM stats (%s) exponent: %i",
                                    pdesc->name, pdesc->exponent);
                        break;
                case KVM_STATS_UNIT_BOOLEAN:
                        TEST_ASSERT(pdesc->exponent == 0,
                                    "Unsupported KVM stats (%s) exponent: %d",
                                    pdesc->name, pdesc->exponent);
                        break;
                }

                /* Check size field, which should not be zero */
                TEST_ASSERT(pdesc->size,
                            "KVM descriptor(%s) with size of 0", pdesc->name);
                /* Check bucket_size field */
                switch (pdesc->flags & KVM_STATS_TYPE_MASK) {
                case KVM_STATS_TYPE_LINEAR_HIST:
                        TEST_ASSERT(pdesc->bucket_size,
                                    "Bucket size of Linear Histogram stats (%s) is zero",
                                    pdesc->name);
                        break;
                default:
                        TEST_ASSERT(!pdesc->bucket_size,
                                    "Bucket size of stats (%s) is not zero",
                                    pdesc->name);
                }
                size_data = max(size_data, pdesc->offset + pdesc->size * sizeof(*stats_data));
        }

        /*
         * Now that the size of the data block is known, verify the data block
         * doesn't overlap the descriptor block.
         */
        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");

        /* 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 */
        for (i = 0; i < header.num_desc; ++i) {
                pdesc = get_stats_descriptor(stats_desc, i, &header);
                read_stat_data(stats_fd, &header, pdesc, stats_data,
                               pdesc->size);
        }

        free(stats_data);
        free(stats_desc);
        free(id);

        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 vm_stats_fds, *vcpu_stats_fds;
        int i, j;
        struct kvm_vcpu **vcpus;
        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;
        }

        ksft_print_header();

        /* Check the extension for binary stats */
        TEST_REQUIRE(kvm_has_cap(KVM_CAP_BINARY_STATS_FD));

        ksft_set_plan(max_vm);

        /* Create VMs and VCPUs */
        vms = malloc(sizeof(vms[0]) * max_vm);
        TEST_ASSERT(vms, "Allocate memory for storing VM pointers");

        vcpus = malloc(sizeof(struct kvm_vcpu *) * max_vm * max_vcpu);
        TEST_ASSERT(vcpus, "Allocate memory for storing vCPU pointers");

        /*
         * Not per-VM as the array is populated, used, and invalidated within a
         * single for-loop iteration.
         */
        vcpu_stats_fds = calloc(max_vm, sizeof(*vcpu_stats_fds));
        TEST_ASSERT(vcpu_stats_fds, "Allocate memory for VM stats fds");

        for (i = 0; i < max_vm; ++i) {
                vms[i] = vm_create_barebones();
                for (j = 0; j < max_vcpu; ++j)
                        vcpus[i * max_vcpu + j] = __vm_vcpu_add(vms[i], j);
        }

        /*
         * Check stats read for every VM and vCPU, with a variety of flavors.
         * Note, stats_test() closes the passed in stats fd.
         */
        for (i = 0; i < max_vm; ++i) {
                /*
                 * Verify that creating multiple userspace references to a
                 * single stats file works and doesn't cause explosions.
                 */
                vm_stats_fds = vm_get_stats_fd(vms[i]);
                stats_test(kvm_dup(vm_stats_fds));

                /* Verify userspace can instantiate multiple stats files. */
                stats_test(vm_get_stats_fd(vms[i]));

                for (j = 0; j < max_vcpu; ++j) {
                        vcpu_stats_fds[j] = vcpu_get_stats_fd(vcpus[i * max_vcpu + j]);
                        stats_test(kvm_dup(vcpu_stats_fds[j]));
                        stats_test(vcpu_get_stats_fd(vcpus[i * max_vcpu + j]));
                }

                /*
                 * Close the VM fd and redo the stats tests.  KVM should gift a
                 * reference (to the VM) to each stats fd, i.e. stats should
                 * still be accessible even after userspace has put its last
                 * _direct_ reference to the VM.
                 */
                kvm_vm_free(vms[i]);

                stats_test(vm_stats_fds);
                for (j = 0; j < max_vcpu; ++j)
                        stats_test(vcpu_stats_fds[j]);

                ksft_test_result_pass("vm%i\n", i);
        }

        free(vms);
        free(vcpus);
        free(vcpu_stats_fds);

        ksft_finished();        /* Print results and exit() accordingly */
}