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/*
* Copyright (c) 2021 EPAM Systems
* Copyright (c) 2022 Arm Limited (or its affiliates). All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/arch/arm64/hypercall.h>
#include <zephyr/xen/public/xen.h>
#include <zephyr/xen/public/event_channel.h>
#include <zephyr/xen/events.h>
#include <zephyr/sys/barrier.h>
#include <errno.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/irq.h>
LOG_MODULE_REGISTER(xen_events);
extern shared_info_t *HYPERVISOR_shared_info;
static evtchn_handle_t event_channels[EVTCHN_2L_NR_CHANNELS];
static bool events_missed[EVTCHN_2L_NR_CHANNELS];
static void empty_callback(void *data)
{
/* data is the event_channels entry, subtracting the base, it's the port */
unsigned int port = (((evtchn_handle_t *)data) - event_channels);
events_missed[port] = true;
}
int alloc_unbound_event_channel(domid_t remote_dom)
{
int rc;
struct evtchn_alloc_unbound alloc = {
.dom = DOMID_SELF,
.remote_dom = remote_dom,
};
rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &alloc);
if (rc == 0) {
rc = alloc.port;
}
return rc;
}
int bind_interdomain_event_channel(domid_t remote_dom, evtchn_port_t remote_port,
evtchn_cb_t cb, void *data)
{
int rc;
struct evtchn_bind_interdomain bind = {
.remote_dom = remote_dom,
.remote_port = remote_port,
};
rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain, &bind);
if (rc < 0) {
return rc;
}
rc = bind_event_channel(bind.local_port, cb, data);
if (rc < 0) {
return rc;
}
return bind.local_port;
}
int evtchn_status(evtchn_status_t *status)
{
return HYPERVISOR_event_channel_op(EVTCHNOP_status, status);
}
int evtchn_close(evtchn_port_t port)
{
struct evtchn_close close = {
.port = port,
};
return HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
}
int evtchn_set_priority(evtchn_port_t port, uint32_t priority)
{
struct evtchn_set_priority set = {
.port = port,
.priority = priority,
};
return HYPERVISOR_event_channel_op(EVTCHNOP_set_priority, &set);
}
void notify_evtchn(evtchn_port_t port)
{
struct evtchn_send send;
__ASSERT(port < EVTCHN_2L_NR_CHANNELS,
"%s: trying to send notify for invalid evtchn #%u\n",
__func__, port);
send.port = port;
HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
}
int bind_event_channel(evtchn_port_t port, evtchn_cb_t cb, void *data)
{
__ASSERT(port < EVTCHN_2L_NR_CHANNELS,
"%s: trying to bind invalid evtchn #%u\n",
__func__, port);
__ASSERT(cb != NULL, "%s: NULL callback for evtchn #%u\n",
__func__, port);
if (event_channels[port].cb != empty_callback)
LOG_WRN("%s: re-bind callback for evtchn #%u\n",
__func__, port);
event_channels[port].priv = data;
event_channels[port].cb = cb;
return 0;
}
int unbind_event_channel(evtchn_port_t port)
{
__ASSERT(port < EVTCHN_2L_NR_CHANNELS,
"%s: trying to unbind invalid evtchn #%u\n",
__func__, port);
event_channels[port].cb = empty_callback;
event_channels[port].priv = &event_channels[port];
events_missed[port] = false;
return 0;
}
int get_missed_events(evtchn_port_t port)
{
__ASSERT(port < EVTCHN_2L_NR_CHANNELS,
"%s: trying to get missed event from invalid port #%u\n",
__func__, port);
if (events_missed[port]) {
events_missed[port] = false;
return 1;
}
return 0;
}
int mask_event_channel(evtchn_port_t port)
{
shared_info_t *s = HYPERVISOR_shared_info;
__ASSERT(port < EVTCHN_2L_NR_CHANNELS,
"%s: trying to mask invalid evtchn #%u\n",
__func__, port);
sys_bitfield_set_bit((mem_addr_t) s->evtchn_mask, port);
return 0;
}
int unmask_event_channel(evtchn_port_t port)
{
shared_info_t *s = HYPERVISOR_shared_info;
__ASSERT(port < EVTCHN_2L_NR_CHANNELS,
"%s: trying to unmask invalid evtchn #%u\n",
__func__, port);
sys_bitfield_clear_bit((mem_addr_t) s->evtchn_mask, port);
return 0;
}
static void clear_event_channel(evtchn_port_t port)
{
shared_info_t *s = HYPERVISOR_shared_info;
sys_bitfield_clear_bit((mem_addr_t) s->evtchn_pending, port);
}
static inline xen_ulong_t get_pending_events(xen_ulong_t pos)
{
shared_info_t *s = HYPERVISOR_shared_info;
return (s->evtchn_pending[pos] & ~(s->evtchn_mask[pos]));
}
static void process_event(evtchn_port_t port)
{
evtchn_handle_t channel = event_channels[port];
clear_event_channel(port);
channel.cb(channel.priv);
}
static void events_isr(void *data)
{
ARG_UNUSED(data);
/* Needed for 2-level unwrapping */
xen_ulong_t pos_selector; /* bits are positions in pending array */
xen_ulong_t events_pending; /* bits - events in pos_selector element */
uint32_t pos_index, event_index; /* bit indexes */
evtchn_port_t port; /* absolute event index */
/* TODO: SMP? XEN_LEGACY_MAX_VCPUS == 1*/
vcpu_info_t *vcpu = &HYPERVISOR_shared_info->vcpu_info[0];
/*
* Need to set it to 0 /before/ checking for pending work, thus
* avoiding a set-and-check race (check struct vcpu_info_t)
*/
vcpu->evtchn_upcall_pending = 0;
barrier_dmem_fence_full();
/* Can not use system atomic_t/atomic_set() due to 32-bit casting */
pos_selector = __atomic_exchange_n(&vcpu->evtchn_pending_sel,
0, __ATOMIC_SEQ_CST);
while (pos_selector) {
/* Find first position, clear it in selector and process */
pos_index = __builtin_ffsl(pos_selector) - 1;
pos_selector &= ~(((xen_ulong_t) 1) << pos_index);
/* Find all active evtchn on selected position */
while ((events_pending = get_pending_events(pos_index)) != 0) {
event_index = __builtin_ffsl(events_pending) - 1;
events_pending &= (((xen_ulong_t) 1) << event_index);
port = (pos_index * 8 * sizeof(xen_ulong_t))
+ event_index;
process_event(port);
}
}
}
int xen_events_init(void)
{
int i;
if (!HYPERVISOR_shared_info) {
/* shared info was not mapped */
LOG_ERR("%s: shared_info - NULL, can't setup events\n", __func__);
return -EINVAL;
}
/* bind all ports with default callback */
for (i = 0; i < EVTCHN_2L_NR_CHANNELS; i++) {
event_channels[i].cb = empty_callback;
event_channels[i].priv = &event_channels[i];
events_missed[i] = false;
}
IRQ_CONNECT(DT_IRQ_BY_IDX(DT_INST(0, xen_xen), 0, irq),
DT_IRQ_BY_IDX(DT_INST(0, xen_xen), 0, priority), events_isr,
NULL, DT_IRQ_BY_IDX(DT_INST(0, xen_xen), 0, flags));
irq_enable(DT_IRQ_BY_IDX(DT_INST(0, xen_xen), 0, irq));
LOG_INF("%s: events inited\n", __func__);
return 0;
}