/*
 * 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 "common.h"

static void
should_eq_u64(const char *field_name, uint64_t a, uint64_t b)
{
        if (a != b) {
                errx(EXIT_FAILURE, "unexpected %s %" PRIu64 " != %" PRIu64,
                    field_name, a, b);
        }
}

static void
check_inval_field(int vmfd, uint32_t ident, uint64_t val)
{
        struct vdi_field_entry_v1 field = {
                .vfe_ident = ident,
                .vfe_value = val,
        };
        struct vm_data_xfer vdx = {
                .vdx_class = VDC_VMM_ARCH,
                .vdx_version = 1,
                .vdx_len = sizeof (field),
                .vdx_data = &field,
        };

        if (ioctl(vmfd, VM_DATA_WRITE, &vdx) == 0) {
                err(EXIT_FAILURE, "vmm_data_write should have failed");
        }
        int err = errno;
        if (err != EINVAL) {
                errx(EXIT_FAILURE, "expected EINVAL errno, got %d", err);
        }
}

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);
        }
}

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 vdi_field_entry_v1 fields[4] = {
                { .vfe_ident = VAI_PEND_NMI },
                { .vfe_ident = VAI_PEND_EXTINT },
                { .vfe_ident = VAI_PEND_EXCP },
                { .vfe_ident = VAI_PEND_INTINFO },
        };

        struct vm_data_xfer vdx = {
                .vdx_class = VDC_VMM_ARCH,
                .vdx_version = 1,
                .vdx_flags = VDX_FLAG_READ_COPYIN,
                .vdx_len = sizeof (fields),
                .vdx_data = &fields,
        };

        /* Fetch arch state first */
        do_data_read(vmfd, &vdx);

        /* All of these should be zeroed on a fresh vcpu */
        should_eq_u64("VAI_PEND_NMI", fields[0].vfe_value, 0);
        should_eq_u64("VAI_PEND_EXTINT", fields[1].vfe_value, 0);
        should_eq_u64("VAI_PEND_EXCP", fields[2].vfe_value, 0);
        should_eq_u64("VAI_PEND_INTINFO", fields[3].vfe_value, 0);

        /* Light up those fields */
        fields[0].vfe_value = 1;
        fields[1].vfe_value = 1;
        fields[2].vfe_value = VM_INTINFO_VALID | VM_INTINFO_HWEXCP | IDT_GP;
        fields[3].vfe_value = VM_INTINFO_VALID | VM_INTINFO_SWINTR | 0x80;
        do_data_write(vmfd, &vdx);

        /*
         * Flip the order (just for funsies) and re-query to check that we still
         * get the expected state.
         */
        fields[0].vfe_ident = VAI_PEND_INTINFO;
        fields[1].vfe_ident = VAI_PEND_EXCP;
        fields[2].vfe_ident = VAI_PEND_EXTINT;
        fields[3].vfe_ident = VAI_PEND_NMI;
        do_data_read(vmfd, &vdx);

        should_eq_u64("VAI_PEND_INTINFO", fields[0].vfe_value,
            VM_INTINFO_VALID | VM_INTINFO_SWINTR | 0x80);
        should_eq_u64("VAI_PEND_EXCP", fields[1].vfe_value,
            VM_INTINFO_VALID | VM_INTINFO_HWEXCP | IDT_GP);
        should_eq_u64("VAI_PEND_EXTINT", fields[2].vfe_value, 1);
        should_eq_u64("VAI_PEND_NMI", fields[3].vfe_value, 1);


        /* NMI-typed exception with the wrong vector */
        check_inval_field(vmfd, VAI_PEND_INTINFO,
            VM_INTINFO_VALID | VM_INTINFO_NMI | 0xd);

        /* Hardware exception with a bad vector (>= 32) */
        check_inval_field(vmfd, VAI_PEND_INTINFO,
            VM_INTINFO_VALID | VM_INTINFO_HWEXCP | 0x40);

        /* Non-HW event injected into HW exception field */
        check_inval_field(vmfd, VAI_PEND_EXCP,
            VM_INTINFO_VALID | VM_INTINFO_SWINTR | 0xd);

        /* Zero out the values again */
        fields[0].vfe_value = 0;
        fields[1].vfe_value = 0;
        fields[2].vfe_value = 0;
        fields[3].vfe_value = 0;
        do_data_write(vmfd, &vdx);

        /* And confirm that it took */
        do_data_read(vmfd, &vdx);
        should_eq_u64("VAI_PEND_INTINFO", fields[0].vfe_value, 0);
        should_eq_u64("VAI_PEND_EXCP", fields[1].vfe_value, 0);
        should_eq_u64("VAI_PEND_EXTINT", fields[2].vfe_value, 0);
        should_eq_u64("VAI_PEND_NMI", fields[3].vfe_value, 0);

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