// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2021, Google LLC.
 *
 * Tests for adjusting the system counter from userspace
 */
#include <asm/kvm_para.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"

#ifdef __x86_64__

struct test_case {
        uint64_t tsc_offset;
};

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

static void check_preconditions(struct kvm_vcpu *vcpu)
{
        __TEST_REQUIRE(!__vcpu_has_device_attr(vcpu, KVM_VCPU_TSC_CTRL,
                                               KVM_VCPU_TSC_OFFSET),
                       "KVM_VCPU_TSC_OFFSET not supported; skipping test");
}

static void setup_system_counter(struct kvm_vcpu *vcpu, struct test_case *test)
{
        vcpu_device_attr_set(vcpu, KVM_VCPU_TSC_CTRL, KVM_VCPU_TSC_OFFSET,
                             &test->tsc_offset);
}

static uint64_t guest_read_system_counter(struct test_case *test)
{
        return rdtsc();
}

static uint64_t host_read_guest_system_counter(struct test_case *test)
{
        return rdtsc() + test->tsc_offset;
}

#else /* __x86_64__ */

#error test not implemented for this architecture!

#endif

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

static void guest_main(void)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
                struct test_case *test = &test_cases[i];

                GUEST_SYNC_CLOCK(i, guest_read_system_counter(test));
        }
}

static void handle_sync(struct ucall *uc, uint64_t start, uint64_t end)
{
        uint64_t obs = uc->args[2];

        TEST_ASSERT(start <= obs && obs <= end,
                    "unexpected system counter value: %"PRIu64" expected range: [%"PRIu64", %"PRIu64"]",
                    obs, start, end);

        pr_info("system counter value: %"PRIu64" expected range [%"PRIu64", %"PRIu64"]\n",
                obs, start, end);
}

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

static void enter_guest(struct kvm_vcpu *vcpu)
{
        uint64_t start, end;
        struct ucall uc;
        int i;

        for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
                struct test_case *test = &test_cases[i];

                setup_system_counter(vcpu, test);
                start = host_read_guest_system_counter(test);
                vcpu_run(vcpu);
                end = host_read_guest_system_counter(test);

                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",
                                    get_ucall(vcpu, &uc));
                }
        }
}

int main(void)
{
        struct kvm_vcpu *vcpu;
        struct kvm_vm *vm;

        vm = vm_create_with_one_vcpu(&vcpu, guest_main);
        check_preconditions(vcpu);

        enter_guest(vcpu);
        kvm_vm_free(vm);
}