/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2023 Oxide Computer Company
 */

/*
 * Test that adjusting the guest TSC with VMM time data interface is visible
 * in guest.
 *
 * Note: requires `vmm_allow_state_writes` to be set
 */

#include <unistd.h>
#include <stdlib.h>
#include <libgen.h>
#include <errno.h>
#include <err.h>

#include <sys/vmm_data.h>
#include <sys/vmm_dev.h>
#include <vmmapi.h>

#include "in_guest.h"

int
main(int argc, char *argv[])
{
        const char *test_suite_name = basename(argv[0]);
        struct vmctx *ctx = NULL;
        struct vcpu *vcpu;
        int err;

        ctx = test_initialize(test_suite_name);

        if ((vcpu = vm_vcpu_open(ctx, 0)) == NULL) {
                test_fail_errno(errno, "Could not open vcpu0");
        }

        err = test_setup_vcpu(vcpu, MEM_LOC_PAYLOAD, MEM_LOC_STACK);
        if (err != 0) {
                test_fail_errno(err, "Could not initialize vcpu0");
        }

        const int vmfd = vm_get_device_fd(ctx);

        /* Read time data to get baseline guest time values */
        struct vdi_time_info_v1 time_info;
        struct vm_data_xfer xfer = {
                .vdx_class = VDC_VMM_TIME,
                .vdx_version = 1,
                .vdx_len = sizeof (struct vdi_time_info_v1),
                .vdx_data = &time_info,
        };
        if (ioctl(vmfd, VM_DATA_READ, &xfer) != 0) {
                errx(EXIT_FAILURE, "VMM_DATA_READ of time info failed");
        }

        /* Change the guest TSC to a much larger value */
        uint64_t expect_tsc = 500000000000;
        time_info.vt_guest_tsc = expect_tsc;
        if (ioctl(vmfd, VM_DATA_WRITE, &xfer) != 0) {
                int error;
                error = errno;
                if (error == EPERM) {
                        warn("VMM_DATA_WRITE got EPERM: is "
                            "vmm_allow_state_writes set?");
                }
                errx(EXIT_FAILURE, "VMM_DATA_WRITE of time info failed");
        }

        struct vm_entry ventry = { 0 };
        struct vm_exit vexit = { 0 };

        bool half_read = false;
        uint64_t tsc;

        do {
                const enum vm_exit_kind kind =
                    test_run_vcpu(vcpu, &ventry, &vexit);

                if (kind == VEK_REENTR) {
                        continue;
                } else if (kind != VEK_UNHANDLED) {
                        test_fail_vmexit(&vexit);
                }

                uint32_t val;
                if (vexit_match_inout(&vexit, false, IOP_TEST_VALUE, 4,
                    &val)) {
                        if (!half_read) {
                                /* low 32-bits of TSC first */
                                tsc = val;
                                half_read = true;
                                ventry_fulfill_inout(&vexit, &ventry, 0);
                        } else {
                                /* high 32-bits of TSC */
                                tsc |= ((uint64_t)val << 32);

                                /*
                                 * Check that the TSC reading is at least the
                                 * absurdly high value it was set to.
                                 */
                                if (tsc >= expect_tsc) {
                                        (void) printf("tsc=%ld\n", tsc);
                                        test_pass();
                                } else {
                                        test_fail_msg("TSC %lu < %lu\n", tsc,
                                            expect_tsc);
                                }
                        }
                } else {
                        test_fail_vmexit(&vexit);
                }
        } while (true);
}