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![Anastasiia Lukianenko](/assets/img/avatar_default.png)
Implement Xen para-virtual frontend to backend communication and actually read/write disk data. This is based on mini-os implementation of the para-virtual block frontend driver. Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
200 lines
4.3 KiB
C
200 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* (C) 2003 - Rolf Neugebauer - Intel Research Cambridge
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* (C) 2005 - Grzegorz Milos - Intel Research Cambridge
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* (C) 2020 - EPAM Systems Inc.
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*
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* File: events.c [1]
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* Author: Rolf Neugebauer (neugebar@dcs.gla.ac.uk)
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* Changes: Grzegorz Milos (gm281@cam.ac.uk)
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*
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* Date: Jul 2003, changes Jun 2005
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*
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* Description: Deals with events received on event channels
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*
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* [1] - http://xenbits.xen.org/gitweb/?p=mini-os.git;a=summary
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*/
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#include <common.h>
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#include <log.h>
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#include <asm/io.h>
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#include <asm/xen/system.h>
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#include <xen/events.h>
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#include <xen/hvm.h>
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extern u32 console_evtchn;
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#define NR_EVS 1024
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/**
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* struct _ev_action - represents a event handler.
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*
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* Chaining or sharing is not allowed
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*/
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struct _ev_action {
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void (*handler)(evtchn_port_t port, struct pt_regs *regs, void *data);
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void *data;
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u32 count;
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};
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static struct _ev_action ev_actions[NR_EVS];
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void default_handler(evtchn_port_t port, struct pt_regs *regs, void *data);
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static unsigned long bound_ports[NR_EVS / (8 * sizeof(unsigned long))];
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void unbind_all_ports(void)
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{
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int i;
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int cpu = 0;
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struct shared_info *s = HYPERVISOR_shared_info;
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struct vcpu_info *vcpu_info = &s->vcpu_info[cpu];
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for (i = 0; i < NR_EVS; i++) {
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if (i == console_evtchn)
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continue;
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if (test_and_clear_bit(i, bound_ports)) {
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printf("port %d still bound!\n", i);
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unbind_evtchn(i);
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}
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}
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vcpu_info->evtchn_upcall_pending = 0;
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vcpu_info->evtchn_pending_sel = 0;
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}
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int do_event(evtchn_port_t port, struct pt_regs *regs)
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{
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struct _ev_action *action;
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clear_evtchn(port);
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if (port >= NR_EVS) {
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printk("WARN: do_event(): Port number too large: %d\n", port);
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return 1;
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}
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action = &ev_actions[port];
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action->count++;
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/* call the handler */
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action->handler(port, regs, action->data);
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return 1;
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}
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evtchn_port_t bind_evtchn(evtchn_port_t port,
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void (*handler)(evtchn_port_t, struct pt_regs *, void *),
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void *data)
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{
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if (ev_actions[port].handler != default_handler)
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printf("WARN: Handler for port %d already registered, replacing\n",
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port);
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ev_actions[port].data = data;
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wmb();
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ev_actions[port].handler = handler;
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synch_set_bit(port, bound_ports);
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return port;
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}
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/**
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* unbind_evtchn() - Unbind event channel for selected port
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*/
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void unbind_evtchn(evtchn_port_t port)
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{
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struct evtchn_close close;
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int rc;
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if (ev_actions[port].handler == default_handler)
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debug("Default handler for port %d when unbinding\n", port);
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mask_evtchn(port);
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clear_evtchn(port);
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ev_actions[port].handler = default_handler;
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wmb();
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ev_actions[port].data = NULL;
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synch_clear_bit(port, bound_ports);
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close.port = port;
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rc = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
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if (rc)
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printf("WARN: close_port %d failed rc=%d. ignored\n", port, rc);
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}
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void default_handler(evtchn_port_t port, struct pt_regs *regs, void *ignore)
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{
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debug("[Port %d] - event received\n", port);
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}
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/**
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* evtchn_alloc_unbound() - Create a port available to the pal for
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* exchanging notifications.
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*
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* Unfortunate confusion of terminology: the port is unbound as far
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* as Xen is concerned, but we automatically bind a handler to it.
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*
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* Return: The result of the hypervisor call.
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*/
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int evtchn_alloc_unbound(domid_t pal,
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void (*handler)(evtchn_port_t, struct pt_regs *, void *),
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void *data, evtchn_port_t *port)
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{
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int rc;
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struct evtchn_alloc_unbound op;
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op.dom = DOMID_SELF;
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op.remote_dom = pal;
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rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &op);
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if (rc) {
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printf("ERROR: alloc_unbound failed with rc=%d", rc);
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return rc;
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}
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if (!handler)
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handler = default_handler;
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*port = bind_evtchn(op.port, handler, data);
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return rc;
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}
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/**
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* eventchn_poll() - Event channel polling function
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*
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* Check and process any pending events
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*/
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void eventchn_poll(void)
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{
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do_hypervisor_callback(NULL);
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}
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/**
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* init_events() - Initialize event handler
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*
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* Initially all events are without a handler and disabled.
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*/
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void init_events(void)
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{
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int i;
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debug("%s\n", __func__);
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for (i = 0; i < NR_EVS; i++) {
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ev_actions[i].handler = default_handler;
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mask_evtchn(i);
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}
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}
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/**
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* fini_events() - Close all ports
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*
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* Mask and clear event channels. Close port using EVTCHNOP_close
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* hypercall.
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*/
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void fini_events(void)
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{
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debug("%s\n", __func__);
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/* Dealloc all events */
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unbind_all_ports();
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}
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