/*

 * xen/common/monitor.c

 *

 * Common monitor_op domctl handler.

 *

 * Copyright (c) 2015 Tamas K Lengyel (tamas@tklengyel.com)

 * Copyright (c) 2016, Bitdefender S.R.L.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public

 * License v2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * You should have received a copy of the GNU General Public

 * License along with this program; If not, see <http://www.gnu.org/licenses/>.

 */

#include <xen/event.h>

#include <xen/monitor.h>

#include <xen/sched.h>

#include <xen/vm_event.h>

#include <xsm/xsm.h>

#include <asm/altp2m.h>

#include <asm/monitor.h>

#include <asm/vm_event.h>

int monitor_domctl(struct domain *d, struct xen_domctl_monitor_op *mop)

{

    int rc;

    bool requested_status = false;

    if ( unlikely(current->domain == d) ) /* no domain_pause() */

        return -EPERM;

    rc = xsm_vm_event_control(XSM_PRIV, d, mop->op, mop->event);

    if ( unlikely(rc) )

        return rc;

    switch ( mop->op )

    {

    case XEN_DOMCTL_MONITOR_OP_ENABLE:

        requested_status = true;

        /* fallthrough */

    case XEN_DOMCTL_MONITOR_OP_DISABLE:

        /* sanity check: avoid left-shift undefined behavior */

        if ( unlikely(mop->event > 31) )

            return -EINVAL;

        /* Check if event type is available. */

        if ( unlikely(!(arch_monitor_get_capabilities(d) & (1U << mop->event))) )

            return -EOPNOTSUPP;

        break;

    case XEN_DOMCTL_MONITOR_OP_GET_CAPABILITIES:

        mop->event = arch_monitor_get_capabilities(d);

        return 0;

    default:

        /* The monitor op is probably handled on the arch-side. */

        return arch_monitor_domctl_op(d, mop);

    }

    switch ( mop->event )

    {

    case XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST:

    {

        bool old_status = d->monitor.guest_request_enabled;

        if ( unlikely(old_status == requested_status) )

            return -EEXIST;

        domain_pause(d);

        d->monitor.guest_request_sync = mop->u.guest_request.sync;

        d->monitor.guest_request_enabled = requested_status;

        arch_monitor_allow_userspace(d, mop->u.guest_request.allow_userspace);

        domain_unpause(d);

        break;

    }

    default:

        /* Give arch-side the chance to handle this event */

        return arch_monitor_domctl_event(d, mop);

    }

    return 0;

}

int monitor_traps(struct vcpu *v, bool sync, vm_event_request_t *req)

{

    int rc;

    struct domain *d = v->domain;

    rc = vm_event_claim_slot(d, d->vm_event_monitor);

    switch ( rc )

    {

    case 0:

        break;

    case -ENOSYS:

        /*

         * If there was no ring to handle the event, then

         * simply continue executing normally.

         */

        return 0;

    default:

        return rc;

    };

    req->vcpu_id = v->vcpu_id;

    if ( sync )

    {

        req->flags |= VM_EVENT_FLAG_VCPU_PAUSED;

        vm_event_vcpu_pause(v);

        rc = 1;

    }

    if ( altp2m_active(d) )

    {

        req->flags |= VM_EVENT_FLAG_ALTERNATE_P2M;

        req->altp2m_idx = altp2m_vcpu_idx(v);

    }

    vm_event_fill_regs(req);

    vm_event_put_request(d, d->vm_event_monitor, req);

    return rc;

}

void monitor_guest_request(void)

{

    struct vcpu *curr = current;

    struct domain *d = curr->domain;

    if ( d->monitor.guest_request_enabled )

    {

        vm_event_request_t req = {

            .reason = VM_EVENT_REASON_GUEST_REQUEST,

            .vcpu_id = curr->vcpu_id,

        };

        monitor_traps(curr, d->monitor.guest_request_sync, &req);

    }

}

/*

 * Local variables:

 * mode: C

 * c-file-style: "BSD"

 * c-basic-offset: 4

 * indent-tabs-mode: nil

 * End:

 */