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/******************************************************************************
* event.h
*
* A nice interface for passing asynchronous events to guest OSes.
*
* Copyright (c) 2002, K A Fraser
*/
#ifndef __XEN_EVENT_H__
#define __XEN_EVENT_H__
#include <xen/config.h>
#include <xen/sched.h>
#include <xen/smp.h>
#include <asm/bitops.h>
/*
* EVENT-CHANNEL NOTIFICATIONS
* NB. On x86, the atomic bit operations also act as memory barriers. There
* is therefore sufficiently strict ordering for this architecture -- others
* may require explicit memory barriers.
*/
static inline void evtchn_set_pending(struct vcpu *v, int port)
{
struct domain *d = v->domain;
shared_info_t *s = d->shared_info;
int running;
/* These three operations must happen in strict order. */
if ( !test_and_set_bit(port, &s->evtchn_pending[0]) &&
!test_bit (port, &s->evtchn_mask[0]) &&
!test_and_set_bit(port>>5, &v->vcpu_info->evtchn_pending_sel) )
{
/* The VCPU pending flag must be set /after/ update to evtchn-pend. */
set_bit(0, &v->vcpu_info->evtchn_upcall_pending);
/*
* NB1. 'vcpu_flags' and 'processor' must be checked /after/ update of
* pending flag. These values may fluctuate (after all, we hold no
* locks) but the key insight is that each change will cause
* evtchn_upcall_pending to be polled.
*
* NB2. We save VCPUF_running across the unblock to avoid a needless
* IPI for domains that we IPI'd to unblock.
*/
running = test_bit(_VCPUF_running, &v->vcpu_flags);
vcpu_unblock(v);
if ( running )
smp_send_event_check_cpu(v->processor);
}
}
/*
* send_guest_virq:
* @v: VCPU to which virtual IRQ should be sent
* @virq: Virtual IRQ number (VIRQ_*)
*/
static inline void send_guest_virq(struct vcpu *v, int virq)
{
int port = v->virq_to_evtchn[virq];
if ( likely(port != 0) )
evtchn_set_pending(v, port);
}
/*
* send_guest_pirq:
* @d: Domain to which physical IRQ should be sent
* @pirq: Physical IRQ number
*/
extern void send_guest_pirq(struct domain *d, int pirq);
#define event_pending(_d) \
((_d)->vcpu_info->evtchn_upcall_pending && \
!(_d)->vcpu_info->evtchn_upcall_mask)
#endif /* __XEN_EVENT_H__ */
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