/*
 * 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
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <libgen.h>
#include <sys/stat.h>
#include <errno.h>
#include <err.h>
#include <assert.h>
#include <sys/sysmacros.h>
#include <stdbool.h>

#include <sys/vmm.h>
#include <sys/vmm_dev.h>
#include <sys/vmm_data.h>
#include <vmmapi.h>
#include <sys/x86_archext.h>
#include <sys/controlregs.h>

#include "common.h"

static void
do_data_write(int vmfd, struct vm_data_xfer *vdx)
{
        if (ioctl(vmfd, VM_DATA_WRITE, vdx) != 0) {
                err(EXIT_FAILURE, "valid vmm_data_write failed");
        }
        if (vdx->vdx_result_len != vdx->vdx_len) {
                errx(EXIT_FAILURE, "unexpected vdx_result_len %u != %u",
                    vdx->vdx_len, vdx->vdx_result_len);
        }
}

static void
do_data_read(int vmfd, struct vm_data_xfer *vdx)
{
        if (ioctl(vmfd, VM_DATA_READ, vdx) != 0) {
                err(EXIT_FAILURE, "valid vmm_data_read failed");
        }
        if (vdx->vdx_result_len != vdx->vdx_len) {
                errx(EXIT_FAILURE, "unexpected vdx_result_len %u != %u",
                    vdx->vdx_len, vdx->vdx_result_len);
        }
}

static uint32_t
query_data_size(int vmfd, struct vm_data_xfer *vdx)
{
        vdx->vdx_len = 0;
        vdx->vdx_data = NULL;
        vdx->vdx_flags = 0;

        if (ioctl(vmfd, VM_DATA_READ, vdx) == 0) {
                errx(EXIT_FAILURE,
                    "expected VM_DATA_READ to fail for size query");
        }
        if (errno != ENOSPC) {
                err(EXIT_FAILURE,
                    "expected ENOSPC error for VM_DATA_READ size query");
        }
        return (vdx->vdx_result_len);
}

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

        ctx = create_test_vm(suite_name);
        if (ctx == NULL) {
                errx(EXIT_FAILURE, "could not open test VM");
        }

        if ((vcpu = vm_vcpu_open(ctx, 0)) == NULL) {
                err(EXIT_FAILURE, "could not open vcpu0");
        }

        if (vm_activate_cpu(vcpu) != 0) {
                err(EXIT_FAILURE, "could not activate vcpu0");
        }

        const int vmfd = vm_get_device_fd(ctx);

        /* Pause the instance before attempting to manipulate vcpu data */
        if (ioctl(vmfd, VM_PAUSE, 0) != 0) {
                err(EXIT_FAILURE, "VM_PAUSE failed");
        }

        struct vm_data_xfer vdx = {
                .vdx_class = VDC_MSR,
                .vdx_version = 1,
                .vdx_vcpuid = 0,
        };

        const uint32_t msr_sz = query_data_size(vmfd, &vdx);
        const uint32_t msr_count = msr_sz / sizeof (struct vdi_field_entry_v1);

        struct vdi_field_entry_v1 *entries =
            calloc(msr_count, sizeof (struct vdi_field_entry_v1));
        if (entries == NULL) {
                err(EXIT_FAILURE, "could not allocate space for MSR data");
        }

        /* Attempt to read all the (default) entries */
        vdx.vdx_data = entries;
        vdx.vdx_len = msr_sz;
        do_data_read(vmfd, &vdx);

        /* Spot check a few MSRs which we expect to be present */
        struct expected_msr {
                const char *name;
                uint32_t msr;
                bool present;
        } spot_check[] = {
                { .msr = MSR_AMD_EFER, .name = "EFER" },
                { .msr = REG_TSC, .name = "TSC" },
                { .msr = MSR_AMD_CSTAR, .name = "CSTAR" },
                { .msr = MSR_AMD_KGSBASE, .name = "KGSBASE" },
        };
        for (uint_t i = 0; i < msr_count; i++) {
                for (uint_t j = 0; j < ARRAY_SIZE(spot_check); j++) {
                        if (spot_check[j].msr == entries[i].vfe_ident) {
                                spot_check[j].present = true;
                        }
                }
        }
        for (uint_t j = 0; j < ARRAY_SIZE(spot_check); j++) {
                if (!spot_check[j].present) {
                        errx(EXIT_FAILURE,
                            "did not find %s(%x) MSR in VM_DATA_READ results",
                            spot_check[j].name, spot_check[j].msr);
                }
        }

        /* Attempt to write those same values back to the instance */
        do_data_write(vmfd, &vdx);
        free(entries);
        entries = NULL;

        /* Do a targeted read of a few values */
        struct vdi_field_entry_v1 small_list[] = {
                { .vfe_ident = REG_TSC },
                { .vfe_ident = MSR_INTC_SEP_EIP },
                { .vfe_ident = REG_PAT },
        };
        vdx.vdx_data = small_list;
        vdx.vdx_len = sizeof (small_list);
        vdx.vdx_flags = VDX_FLAG_READ_COPYIN;
        do_data_read(vmfd, &vdx);

        /*
         * Test access to DEBUGCTL and LBR-related MSRs on AMD.
         *
         * Because support for these varies between CPUs, they are (currently)
         * not included in the default set of MSRs emitted by a blanket read of
         * MSRs via the vmm-data interface.
         */
        if (cpu_vendor_amd()) {
                struct vdi_field_entry_v1 dbg_entries[] = {
                        { .vfe_ident = MSR_DEBUGCTL },
                        { .vfe_ident = MSR_LBR_FROM },
                        { .vfe_ident = MSR_LBR_TO },
                        { .vfe_ident = MSR_LEX_FROM },
                        { .vfe_ident = MSR_LEX_TO },
                };

                vdx.vdx_data = &dbg_entries;
                vdx.vdx_len = sizeof (dbg_entries);
                vdx.vdx_flags = VDX_FLAG_READ_COPYIN;

                do_data_read(vmfd, &vdx);

                vdx.vdx_flags = 0;
                do_data_write(vmfd, &vdx);
        }


        vm_destroy(ctx);
        (void) printf("%s\tPASS\n", suite_name);
        return (EXIT_SUCCESS);
}