blob: 9d6f4076ad4476c4597f5b4651061331860f20fe [file] [log] [blame]
/*
* QEMU Xen emulation: Event channel support
*
* Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Authors: David Woodhouse <dwmw2@infradead.org>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#include "qemu/module.h"
#include "qemu/main-loop.h"
#include "qapi/error.h"
#include "qom/object.h"
#include "exec/target_page.h"
#include "exec/address-spaces.h"
#include "migration/vmstate.h"
#include "hw/sysbus.h"
#include "hw/xen/xen.h"
#include "xen_evtchn.h"
#include "sysemu/kvm.h"
#include "sysemu/kvm_xen.h"
#include <linux/kvm.h>
#include "hw/xen/interface/memory.h"
#include "hw/xen/interface/hvm/params.h"
#define TYPE_XEN_EVTCHN "xen-evtchn"
OBJECT_DECLARE_SIMPLE_TYPE(XenEvtchnState, XEN_EVTCHN)
struct XenEvtchnState {
/*< private >*/
SysBusDevice busdev;
/*< public >*/
uint64_t callback_param;
bool evtchn_in_kernel;
QemuMutex port_lock;
};
struct XenEvtchnState *xen_evtchn_singleton;
/* Top bits of callback_param are the type (HVM_PARAM_CALLBACK_TYPE_xxx) */
#define CALLBACK_VIA_TYPE_SHIFT 56
static int xen_evtchn_post_load(void *opaque, int version_id)
{
XenEvtchnState *s = opaque;
if (s->callback_param) {
xen_evtchn_set_callback_param(s->callback_param);
}
return 0;
}
static bool xen_evtchn_is_needed(void *opaque)
{
return xen_mode == XEN_EMULATE;
}
static const VMStateDescription xen_evtchn_vmstate = {
.name = "xen_evtchn",
.version_id = 1,
.minimum_version_id = 1,
.needed = xen_evtchn_is_needed,
.post_load = xen_evtchn_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT64(callback_param, XenEvtchnState),
VMSTATE_END_OF_LIST()
}
};
static void xen_evtchn_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->vmsd = &xen_evtchn_vmstate;
}
static const TypeInfo xen_evtchn_info = {
.name = TYPE_XEN_EVTCHN,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(XenEvtchnState),
.class_init = xen_evtchn_class_init,
};
void xen_evtchn_create(void)
{
XenEvtchnState *s = XEN_EVTCHN(sysbus_create_simple(TYPE_XEN_EVTCHN,
-1, NULL));
xen_evtchn_singleton = s;
qemu_mutex_init(&s->port_lock);
}
static void xen_evtchn_register_types(void)
{
type_register_static(&xen_evtchn_info);
}
type_init(xen_evtchn_register_types)
int xen_evtchn_set_callback_param(uint64_t param)
{
XenEvtchnState *s = xen_evtchn_singleton;
struct kvm_xen_hvm_attr xa = {
.type = KVM_XEN_ATTR_TYPE_UPCALL_VECTOR,
.u.vector = 0,
};
bool in_kernel = false;
int ret;
if (!s) {
return -ENOTSUP;
}
qemu_mutex_lock(&s->port_lock);
switch (param >> CALLBACK_VIA_TYPE_SHIFT) {
case HVM_PARAM_CALLBACK_TYPE_VECTOR: {
xa.u.vector = (uint8_t)param,
ret = kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &xa);
if (!ret && kvm_xen_has_cap(EVTCHN_SEND)) {
in_kernel = true;
}
break;
}
default:
/* Xen doesn't return error even if you set something bogus */
ret = 0;
break;
}
if (!ret) {
/* If vector delivery was turned *off* then tell the kernel */
if ((s->callback_param >> CALLBACK_VIA_TYPE_SHIFT) ==
HVM_PARAM_CALLBACK_TYPE_VECTOR && !xa.u.vector) {
kvm_vm_ioctl(kvm_state, KVM_XEN_HVM_SET_ATTR, &xa);
}
s->callback_param = param;
s->evtchn_in_kernel = in_kernel;
}
qemu_mutex_unlock(&s->port_lock);
return ret;
}