// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2021, Google LLC.
 *
 * Tests for adjusting the KVM clock from userspace
 */
#include <asm/kvm_para.h>
#include <asm/pvclock.h>
#include <asm/pvclock-abi.h>
#include <stdint.h>
#include <string.h>
#include <sys/stat.h>
#include <time.h>

#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"

struct test_case {
        uint64_t kvmclock_base;
        int64_t realtime_offset;
};

static struct test_case test_cases[] = {
        { .kvmclock_base = 0 },
        { .kvmclock_base = 180 * NSEC_PER_SEC },
        { .kvmclock_base = 0, .realtime_offset = -180 * NSEC_PER_SEC },
        { .kvmclock_base = 0, .realtime_offset = 180 * NSEC_PER_SEC },
};

#define GUEST_SYNC_CLOCK(__stage, __val)                        \
                GUEST_SYNC_ARGS(__stage, __val, 0, 0, 0)

static void guest_main(vm_paddr_t pvti_pa, struct pvclock_vcpu_time_info *pvti)
{
        int i;

        wrmsr(MSR_KVM_SYSTEM_TIME_NEW, pvti_pa | KVM_MSR_ENABLED);
        for (i = 0; i < ARRAY_SIZE(test_cases); i++)
                GUEST_SYNC_CLOCK(i, __pvclock_read_cycles(pvti, rdtsc()));
}

#define EXPECTED_FLAGS (KVM_CLOCK_REALTIME | KVM_CLOCK_HOST_TSC)

static inline void assert_flags(struct kvm_clock_data *data)
{
        TEST_ASSERT((data->flags & EXPECTED_FLAGS) == EXPECTED_FLAGS,
                    "unexpected clock data flags: %x (want set: %x)",
                    data->flags, EXPECTED_FLAGS);
}

static void handle_sync(struct ucall *uc, struct kvm_clock_data *start,
                        struct kvm_clock_data *end)
{
        uint64_t obs, exp_lo, exp_hi;

        obs = uc->args[2];
        exp_lo = start->clock;
        exp_hi = end->clock;

        assert_flags(start);
        assert_flags(end);

        TEST_ASSERT(exp_lo <= obs && obs <= exp_hi,
                    "unexpected kvm-clock value: %"PRIu64" expected range: [%"PRIu64", %"PRIu64"]",
                    obs, exp_lo, exp_hi);

        pr_info("kvm-clock value: %"PRIu64" expected range [%"PRIu64", %"PRIu64"]\n",
                obs, exp_lo, exp_hi);
}

static void handle_abort(struct ucall *uc)
{
        REPORT_GUEST_ASSERT(*uc);
}

static void setup_clock(struct kvm_vm *vm, struct test_case *test_case)
{
        struct kvm_clock_data data;

        memset(&data, 0, sizeof(data));

        data.clock = test_case->kvmclock_base;
        if (test_case->realtime_offset) {
                struct timespec ts;
                int r;

                data.flags |= KVM_CLOCK_REALTIME;
                do {
                        r = clock_gettime(CLOCK_REALTIME, &ts);
                        if (!r)
                                break;
                } while (errno == EINTR);

                TEST_ASSERT(!r, "clock_gettime() failed: %d", r);

                data.realtime = ts.tv_sec * NSEC_PER_SEC;
                data.realtime += ts.tv_nsec;
                data.realtime += test_case->realtime_offset;
        }

        vm_ioctl(vm, KVM_SET_CLOCK, &data);
}

static void enter_guest(struct kvm_vcpu *vcpu)
{
        struct kvm_clock_data start, end;
        struct kvm_vm *vm = vcpu->vm;
        struct ucall uc;
        int i;

        for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
                setup_clock(vm, &test_cases[i]);

                vm_ioctl(vm, KVM_GET_CLOCK, &start);

                vcpu_run(vcpu);
                vm_ioctl(vm, KVM_GET_CLOCK, &end);

                TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);

                switch (get_ucall(vcpu, &uc)) {
                case UCALL_SYNC:
                        handle_sync(&uc, &start, &end);
                        break;
                case UCALL_ABORT:
                        handle_abort(&uc);
                        return;
                default:
                        TEST_ASSERT(0, "unhandled ucall: %ld", uc.cmd);
                }
        }
}

int main(void)
{
        struct kvm_vcpu *vcpu;
        vm_vaddr_t pvti_gva;
        vm_paddr_t pvti_gpa;
        struct kvm_vm *vm;
        int flags;

        flags = kvm_check_cap(KVM_CAP_ADJUST_CLOCK);
        TEST_REQUIRE(flags & KVM_CLOCK_REALTIME);

        TEST_REQUIRE(sys_clocksource_is_based_on_tsc());

        vm = vm_create_with_one_vcpu(&vcpu, guest_main);

        pvti_gva = vm_vaddr_alloc(vm, getpagesize(), 0x10000);
        pvti_gpa = addr_gva2gpa(vm, pvti_gva);
        vcpu_args_set(vcpu, 2, pvti_gpa, pvti_gva);

        enter_guest(vcpu);
        kvm_vm_free(vm);
}