/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * arch/arm/hvm.c
 *
 * Arch-specific hardware virtual machine abstractions.
 */

#include <xen/init.h>
#include <xen/lib.h>
#include <xen/errno.h>
#include <xen/guest_access.h>
#include <xen/hypercall.h>
#include <xen/sched.h>
#include <xen/monitor.h>

#include <xsm/xsm.h>

#include <public/xen.h>
#include <public/hvm/params.h>
#include <public/hvm/hvm_op.h>

static int hvm_allow_set_param(const struct domain *d, unsigned int param)
{
    switch ( param )
    {
        /*
         * The following parameters are intended for toolstack usage only.
         * They may not be set by the domain.
         *
         * The {STORE,CONSOLE}_EVTCHN values will need to become read/write to
         * the guest (not just the toolstack) if a new ABI hasn't appeared by
         * the time migration support is added.
         */
    case HVM_PARAM_CALLBACK_IRQ:
    case HVM_PARAM_STORE_PFN:
    case HVM_PARAM_STORE_EVTCHN:
    case HVM_PARAM_CONSOLE_PFN:
    case HVM_PARAM_CONSOLE_EVTCHN:
    case HVM_PARAM_MONITOR_RING_PFN:
        return d == current->domain ? -EPERM : 0;

        /* Writeable only by Xen, hole, deprecated, or out-of-range. */
    default:
        return -EINVAL;
    }
}

static int hvm_allow_get_param(const struct domain *d, unsigned int param)
{
    switch ( param )
    {
        /* The following parameters can be read by the guest and toolstack. */
    case HVM_PARAM_CALLBACK_IRQ:
    case HVM_PARAM_STORE_PFN:
    case HVM_PARAM_STORE_EVTCHN:
    case HVM_PARAM_CONSOLE_PFN:
    case HVM_PARAM_CONSOLE_EVTCHN:
        return 0;

        /*
         * The following parameters are intended for toolstack usage only.
         * They may not be read by the domain.
         */
    case HVM_PARAM_MONITOR_RING_PFN:
        return d == current->domain ? -EPERM : 0;

        /* Hole, deprecated, or out-of-range. */
    default:
        return -EINVAL;
    }
}

long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
{
    long rc = 0;

    switch ( op )
    {
    case HVMOP_set_param:
    case HVMOP_get_param:
    {
        struct xen_hvm_param a;
        struct domain *d;

        if ( copy_from_guest(&a, arg, 1) )
            return -EFAULT;

        d = rcu_lock_domain_by_any_id(a.domid);
        if ( d == NULL )
            return -ESRCH;

        rc = xsm_hvm_param(XSM_TARGET, d, op);
        if ( rc )
            goto param_fail;

        if ( op == HVMOP_set_param )
        {
            rc = hvm_allow_set_param(d, a.index);
            if ( rc )
                goto param_fail;

            d->arch.hvm.params[a.index] = a.value;
        }
        else
        {
            rc = hvm_allow_get_param(d, a.index);
            if ( rc )
                goto param_fail;

            a.value = d->arch.hvm.params[a.index];
            rc = copy_to_guest(arg, &a, 1) ? -EFAULT : 0;
        }

    param_fail:
        rcu_unlock_domain(d);
        break;
    }

    case HVMOP_guest_request_vm_event:
        if ( guest_handle_is_null(arg) )
            monitor_guest_request();
        else
            rc = -EINVAL;
        break;

    default:
    {
        gdprintk(XENLOG_DEBUG, "HVMOP op=%lu: not implemented\n", op);
        rc = -ENOSYS;
        break;
    }
    }

    return rc;
}

/*
 * Local variables:
 * mode: C
 * c-file-style: "BSD"
 * c-basic-offset: 4
 * tab-width: 4
 * indent-tabs-mode: nil
 * End:
 */
