[PATCH v4 06/10] VM communication channels for VM Power Management(Guest).

[Alan Carew <alan.carew-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

Allows for the opening of Virtio-Serial devices on a VM, where a DPDK
application can send packets to the host based monitor. The packet formatted is
specified in channel_commands.h
Each device appears as a serial device in path
/dev/virtio-ports/virtio.serial.port.<agent_type>.<lcore_num> where each lcore
in a DPDK application has exclusive to a device/channel.
Each channel is opened in non-blocking mode, after a successful open a test
packet is send to the host to ensure the host side is monitoring.

Signed-off-by: Alan Carew <alan.carew-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 lib/librte_power/guest_channel.c | 162 +++++++++++++++++++++++++++++++++++++++
 lib/librte_power/guest_channel.h |  89 +++++++++++++++++++++
 2 files changed, 251 insertions(+)
 create mode 100644 lib/librte_power/guest_channel.c
 create mode 100644 lib/librte_power/guest_channel.h

diff --git a/lib/librte_power/guest_channel.c b/lib/librte_power/guest_channel.c
new file mode 100644
index 0000000..2295665
--- /dev/null
+++ b/lib/librte_power/guest_channel.c
@@ -0,0 +1,162 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+
+
+#include <rte_log.h>
+#include <rte_config.h>
+
+#include "guest_channel.h"
+#include "channel_commands.h"
+
+#define RTE_LOGTYPE_GUEST_CHANNEL RTE_LOGTYPE_USER1
+
+static int global_fds[RTE_MAX_LCORE];
+
+int
+guest_channel_host_connect(const char *path, unsigned lcore_id)
+{
+	int flags, ret;
+	struct channel_packet pkt;
+	char fd_path[PATH_MAX];
+	int fd = -1;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 0...%d\n",
+				lcore_id, RTE_MAX_LCORE-1);
+		return -1;
+	}
+	/* check if path is already open */
+	if (global_fds[lcore_id] != 0) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is already open with fd %d\n",
+				lcore_id, global_fds[lcore_id]);
+		return -1;
+	}
+
+	snprintf(fd_path, PATH_MAX, "%s.%u", path, lcore_id);
+	RTE_LOG(INFO, GUEST_CHANNEL, "Opening channel '%s' for lcore %u\n",
+			fd_path, lcore_id);
+	fd = open(fd_path, O_RDWR);
+	if (fd < 0) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Unable to to connect to '%s' with error "
+				"%s\n", fd_path, strerror(errno));
+		return -1;
+	}
+
+	flags = fcntl(fd, F_GETFL, 0);
+	if (flags < 0) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Failed on fcntl get flags for file %s\n",
+				fd_path);
+		goto error;
+	}
+
+	flags |= O_NONBLOCK;
+	if (fcntl(fd, F_SETFL, flags) < 0) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Failed on setting non-blocking mode for "
+				"file %s", fd_path);
+		goto error;
+	}
+	/* QEMU needs a delay after connection */
+	sleep(1);
+
+	/* Send a test packet, this command is ignored by the host, but a successful
+	 * send indicates that the host endpoint is monitoring.
+	 */
+	pkt.command = CPU_POWER_CONNECT;
+	global_fds[lcore_id] = fd;
+	ret = guest_channel_send_msg(&pkt, lcore_id);
+	if (ret != 0) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Error on channel '%s' communications "
+				"test: %s\n", fd_path, strerror(ret));
+		goto error;
+	}
+	RTE_LOG(INFO, GUEST_CHANNEL, "Channel '%s' is now connected\n", fd_path);
+	return 0;
+error:
+	close(fd);
+	global_fds[lcore_id] = 0;
+	return -1;
+}
+
+int
+guest_channel_send_msg(struct channel_packet *pkt, unsigned lcore_id)
+{
+	int ret, buffer_len = sizeof(*pkt);
+	void *buffer = pkt;
+
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 0...%d\n",
+				lcore_id, RTE_MAX_LCORE-1);
+		return -1;
+	}
+
+	if (global_fds[lcore_id] == 0) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Channel is not connected\n");
+		return -1;
+	}
+	while (buffer_len > 0) {
+		ret = write(global_fds[lcore_id], buffer, buffer_len);
+		if (ret == buffer_len)
+			return 0;
+		if (ret == -1) {
+			if (errno == EINTR)
+				continue;
+			return errno;
+		}
+		buffer = (char *)buffer + ret;
+		buffer_len -= ret;
+	}
+	return 0;
+}
+
+void
+guest_channel_host_disconnect(unsigned lcore_id)
+{
+	if (lcore_id >= RTE_MAX_LCORE) {
+		RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 0...%d\n",
+				lcore_id, RTE_MAX_LCORE-1);
+		return;
+	}
+	if (global_fds[lcore_id] == 0)
+		return;
+	close(global_fds[lcore_id]);
+	global_fds[lcore_id] = 0;
+}
diff --git a/lib/librte_power/guest_channel.h b/lib/librte_power/guest_channel.h
new file mode 100644
index 0000000..9e18af5
--- /dev/null
+++ b/lib/librte_power/guest_channel.h
@@ -0,0 +1,89 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef _GUEST_CHANNEL_H
+#define _GUEST_CHANNEL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <channel_commands.h>
+
+/**
+ * Connect to the Virtio-Serial VM end-point located in path. It is
+ * thread safe for unique lcore_ids. This function must be only called once from
+ * each lcore.
+ *
+ * @param path
+ *  The path to the serial device on the filesystem
+ * @param lcore_id
+ *  lcore_id.
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on error.
+ */
+int guest_channel_host_connect(const char *path, unsigned lcore_id);
+
+/**
+ * Disconnect from an already connected Virtio-Serial Endpoint.
+ *
+ *
+ * @param lcore_id
+ *  lcore_id.
+ *
+ */
+void guest_channel_host_disconnect(unsigned lcore_id);
+
+/**
+ * Send a message contained in pkt over the Virtio-Serial to the host endpoint.
+ *
+ * @param pkt
+ *  Pointer to a populated struct guest_agent_pkt
+ *
+ * @param lcore_id
+ *  lcore_id.
+ *
+ * @return
+ *  - 0 on success.
+ *  - Negative on channel not connected.
+ *  - errno on write to channel error.
+ */
+int guest_channel_send_msg(struct channel_packet *pkt, unsigned lcore_id);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
-- 
1.9.3