1 files changed, 174 insertions, 0 deletions
diff --git a/tools/include/xenevtchn.h b/tools/include/xenevtchn.h
new file mode 100644
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+++ b/tools/include/xenevtchn.h
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+/*
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Split off from:
+ * xenctrl.h
+ *
+ * A library for low-level access to the Xen control interfaces.
+ *
+ * Copyright (c) 2003-2004, K A Fraser.
+ */
+
+#ifndef XENEVTCHN_H
+#define XENEVTCHN_H
+
+#include <stdint.h>
+
+#include <xen/event_channel.h>
+
+/* A port identifier is guaranteed to fit in 31 bits. */
+typedef int xenevtchn_port_or_error_t;
+
+typedef struct xenevtchn_handle xenevtchn_handle;
+
+/* Callers who don't care don't need to #include <xentoollog.h> */
+struct xentoollog_logger;
+
+/*
+ * EVENT CHANNEL FUNCTIONS
+ *
+ * None of these do any logging.
+ */
+
+/*
+ * Return a handle to the event channel driver, or NULL on failure, in
+ * which case errno will be set appropriately.
+ *
+ * Note: After fork(2) a child process must not use any opened evtchn
+ * handle inherited from their parent, nor access any grant mapped
+ * areas associated with that handle.
+ *
+ * The child must open a new handle if they want to interact with
+ * evtchn.
+ *
+ * Calling exec(2) in a child will safely (and reliably) reclaim any
+ * allocated resources via a xenevtchn_handle in the parent.
+ *
+ * A child which does not call exec(2) may safely call
+ * xenevtchn_close() on a xenevtchn_handle inherited from their
+ * parent. This will attempt to reclaim any resources associated with
+ * that handle. Note that in some implementations this reclamation may
+ * not be completely effective, in this case any affected resources
+ * remain allocated.
+ *
+ * Calling xenevtchn_close() is the only safe operation on a
+ * xenevtchn_handle which has been inherited.
+ */
+/* Currently no flags are defined */
+xenevtchn_handle *xenevtchn_open(struct xentoollog_logger *logger,
+                                 unsigned open_flags);
+
+/*
+ * Close a handle previously allocated with xenevtchn_open().
+ */
+int xenevtchn_close(xenevtchn_handle *xce);
+
+/*
+ * Return an fd that can be select()ed on.
+ *
+ * Note that due to bugs, setting this fd to non blocking may not
+ * work: you would hope that it would result in xenevtchn_pending
+ * failing with EWOULDBLOCK if there are no events signaled, but in
+ * fact it may block.  (Bug is present in at least Linux 3.12, and
+ * perhaps on other platforms or later version.)
+ *
+ * To be safe, you must use poll() or select() before each call to
+ * xenevtchn_pending.  If you have multiple threads (or processes)
+ * sharing a single xce handle this will not work, and there is no
+ * straightforward workaround.  Please design your program some other
+ * way.
+ */
+int xenevtchn_fd(xenevtchn_handle *xce);
+
+/*
+ * Notify the given event channel. Returns -1 on failure, in which case
+ * errno will be set appropriately.
+ */
+int xenevtchn_notify(xenevtchn_handle *xce, evtchn_port_t port);
+
+/*
+ * Returns a new event port awaiting interdomain connection from the given
+ * domain ID, or -1 on failure, in which case errno will be set appropriately.
+ */
+xenevtchn_port_or_error_t
+xenevtchn_bind_unbound_port(xenevtchn_handle *xce, uint32_t domid);
+
+/*
+ * Returns a new event port bound to the remote port for the given domain ID,
+ * or -1 on failure, in which case errno will be set appropriately.
+ */
+xenevtchn_port_or_error_t
+xenevtchn_bind_interdomain(xenevtchn_handle *xce, uint32_t domid,
+                           evtchn_port_t remote_port);
+
+/*
+ * Bind an event channel to the given VIRQ. Returns the event channel bound to
+ * the VIRQ, or -1 on failure, in which case errno will be set appropriately.
+ */
+xenevtchn_port_or_error_t
+xenevtchn_bind_virq(xenevtchn_handle *xce, unsigned int virq);
+
+/*
+ * Unbind the given event channel. Returns -1 on failure, in which case errno
+ * will be set appropriately.
+ */
+int xenevtchn_unbind(xenevtchn_handle *xce, evtchn_port_t port);
+
+/*
+ * Return the next event channel to become pending, or -1 on failure, in which
+ * case errno will be set appropriately.
+ *
+ * At the hypervisor level the event channel will have been masked,
+ * and then cleared, by the underlying machinery (evtchn kernel
+ * driver, or equivalent).  So if the event channel is signaled again
+ * after it is returned here, it will be queued up, and delivered
+ * again after you unmask it.  (See the documentation in the Xen
+ * public header event_channel.h.)
+ *
+ * On receiving the notification from xenevtchn_pending, you should
+ * normally: check (by other means) what work needs doing; do the
+ * necessary work (if any); unmask the event channel with
+ * xenevtchn_unmask (if you want to receive any further
+ * notifications).
+ */
+xenevtchn_port_or_error_t
+xenevtchn_pending(xenevtchn_handle *xce);
+
+/*
+ * Unmask the given event channel. Returns -1 on failure, in which case errno
+ * will be set appropriately.
+ */
+int xenevtchn_unmask(xenevtchn_handle *xce, evtchn_port_t port);
+
+/**
+ * This function restricts the use of this handle to the specified
+ * domain.
+ *
+ * @parm xce handle to the open evtchn interface
+ * @parm domid the domain id
+ * @return 0 on success, -1 on failure with errno set appropriately.
+ */
+int xenevtchn_restrict(xenevtchn_handle *xce, domid_t domid);
+
+#endif
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */