mirror of https://github.com/acidanthera/audk.git
106 lines
3.0 KiB
C
106 lines
3.0 KiB
C
/******************************************************************************
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* event_channel.h
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*
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* Event channels between domains.
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*
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* SPDX-License-Identifier: MIT
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*
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* Copyright (c) 2003-2004, K A Fraser.
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*/
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#ifndef __XEN_PUBLIC_EVENT_CHANNEL_H__
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#define __XEN_PUBLIC_EVENT_CHANNEL_H__
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#include "xen.h"
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/*
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* `incontents 150 evtchn Event Channels
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*
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* Event channels are the basic primitive provided by Xen for event
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* notifications. An event is the Xen equivalent of a hardware
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* interrupt. They essentially store one bit of information, the event
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* of interest is signalled by transitioning this bit from 0 to 1.
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*
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* Notifications are received by a guest via an upcall from Xen,
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* indicating when an event arrives (setting the bit). Further
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* notifications are masked until the bit is cleared again (therefore,
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* guests must check the value of the bit after re-enabling event
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* delivery to ensure no missed notifications).
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*
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* Event notifications can be masked by setting a flag; this is
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* equivalent to disabling interrupts and can be used to ensure
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* atomicity of certain operations in the guest kernel.
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*
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* Event channels are represented by the evtchn_* fields in
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* struct shared_info and struct vcpu_info.
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*/
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/*
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* ` enum neg_errnoval
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* ` HYPERVISOR_event_channel_op(enum event_channel_op cmd, VOID *args)
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* `
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* @cmd == EVTCHNOP_* (event-channel operation).
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* @args == struct evtchn_* Operation-specific extra arguments (NULL if none).
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*/
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/* ` enum event_channel_op { // EVTCHNOP_* => struct evtchn_* */
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#define EVTCHNOP_close 3
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#define EVTCHNOP_send 4
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#define EVTCHNOP_alloc_unbound 6
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/* ` } */
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typedef UINT32 evtchn_port_t;
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DEFINE_XEN_GUEST_HANDLE (evtchn_port_t);
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/*
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* EVTCHNOP_alloc_unbound: Allocate a port in domain <dom> and mark as
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* accepting interdomain bindings from domain <remote_dom>. A fresh port
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* is allocated in <dom> and returned as <port>.
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* NOTES:
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* 1. If the caller is unprivileged then <dom> must be DOMID_SELF.
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* 2. <rdom> may be DOMID_SELF, allowing loopback connections.
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*/
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struct evtchn_alloc_unbound {
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/* IN parameters */
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domid_t dom, remote_dom;
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/* OUT parameters */
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evtchn_port_t port;
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};
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typedef struct evtchn_alloc_unbound evtchn_alloc_unbound_t;
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/*
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* EVTCHNOP_close: Close a local event channel <port>. If the channel is
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* interdomain then the remote end is placed in the unbound state
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* (EVTCHNSTAT_unbound), awaiting a new connection.
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*/
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struct evtchn_close {
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/* IN parameters. */
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evtchn_port_t port;
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};
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typedef struct evtchn_close evtchn_close_t;
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/*
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* EVTCHNOP_send: Send an event to the remote end of the channel whose local
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* endpoint is <port>.
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*/
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struct evtchn_send {
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/* IN parameters. */
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evtchn_port_t port;
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};
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typedef struct evtchn_send evtchn_send_t;
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#endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */
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/*
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* Local variables:
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* mode: C
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* c-file-style: "BSD"
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* c-basic-offset: 4
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* tab-width: 4
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* indent-tabs-mode: nil
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* End:
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*/
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