From: Olaf Hering <olaf@aepfle.de>
To: xen-devel@lists.xen.org
Cc: Olaf Hering <olaf@aepfle.de>, Keir Fraser <keir@xen.org>,
Ian Campbell <ian.campbell@citrix.com>, Tim Deegan <tim@xen.org>,
Ian Jackson <ian.jackson@eu.citrix.com>,
Jan Beulich <jbeulich@suse.com>
Subject: [PATCH v9 4/6] vscsiif.h: add some notes about xenstore layout
Date: Tue, 23 Feb 2016 11:26:59 +0000 [thread overview]
Message-ID: <1456226821-24545-5-git-send-email-olaf@aepfle.de> (raw)
In-Reply-To: <1456226821-24545-1-git-send-email-olaf@aepfle.de>
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>
Cc: Tim Deegan <tim@xen.org>
---
xen/include/public/io/vscsiif.h | 69 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 69 insertions(+)
diff --git a/xen/include/public/io/vscsiif.h b/xen/include/public/io/vscsiif.h
index e8e38a9..0a4709f 100644
--- a/xen/include/public/io/vscsiif.h
+++ b/xen/include/public/io/vscsiif.h
@@ -104,6 +104,75 @@
* response structures.
*/
+/*
+ * Xenstore format in practice
+ * ===========================
+ *
+ * The backend driver uses a single_host:many_devices notation to manage domU
+ * devices. Everything is stored in /local/domain/<backend_domid>/backend/vscsi/.
+ * The xenstore layout looks like this (dom0 is assumed to be the backend_domid):
+ *
+ * <domid>/<vhost>/feature-host = "0"
+ * <domid>/<vhost>/frontend = "/local/domain/<domid>/device/vscsi/0"
+ * <domid>/<vhost>/frontend-id = "<domid>"
+ * <domid>/<vhost>/online = "1"
+ * <domid>/<vhost>/state = "4"
+ * <domid>/<vhost>/vscsi-devs/dev-0/p-dev = "8:0:2:1" or "naa.wwn:lun"
+ * <domid>/<vhost>/vscsi-devs/dev-0/state = "4"
+ * <domid>/<vhost>/vscsi-devs/dev-0/v-dev = "0:0:0:0"
+ * <domid>/<vhost>/vscsi-devs/dev-1/p-dev = "8:0:2:2"
+ * <domid>/<vhost>/vscsi-devs/dev-1/state = "4"
+ * <domid>/<vhost>/vscsi-devs/dev-1/v-dev = "0:0:1:0"
+ *
+ * The frontend driver maintains its state in
+ * /local/domain/<domid>/device/vscsi/.
+ *
+ * <vhost>/backend = "/local/domain/0/backend/vscsi/<domid>/<vhost>"
+ * <vhost>/backend-id = "0"
+ * <vhost>/event-channel = "20"
+ * <vhost>/ring-ref = "43"
+ * <vhost>/state = "4"
+ * <vhost>/vscsi-devs/dev-0/state = "4"
+ * <vhost>/vscsi-devs/dev-1/state = "4"
+ *
+ * In addition to the entries for backend and frontend these flags are stored
+ * for the toolstack:
+ *
+ * <domid>/<vhost>/vscsi-devs/dev-1/p-devname = "/dev/$device"
+ * <domid>/<vhost>/libxl_ctrl_index = "0"
+ *
+ *
+ * Backend/frontend protocol
+ * =========================
+ *
+ * To create a vhost along with a device:
+ * <domid>/<vhost>/feature-host = "0"
+ * <domid>/<vhost>/frontend = "/local/domain/<domid>/device/vscsi/0"
+ * <domid>/<vhost>/frontend-id = "<domid>"
+ * <domid>/<vhost>/online = "1"
+ * <domid>/<vhost>/state = "1"
+ * <domid>/<vhost>/vscsi-devs/dev-0/p-dev = "8:0:2:1"
+ * <domid>/<vhost>/vscsi-devs/dev-0/state = "1"
+ * <domid>/<vhost>/vscsi-devs/dev-0/v-dev = "0:0:0:0"
+ * Wait for <domid>/<vhost>/state + <domid>/<vhost>/vscsi-devs/dev-0/state become 4
+ *
+ * To add another device to a vhost:
+ * <domid>/<vhost>/state = "7"
+ * <domid>/<vhost>/vscsi-devs/dev-1/p-dev = "8:0:2:2"
+ * <domid>/<vhost>/vscsi-devs/dev-1/state = "1"
+ * <domid>/<vhost>/vscsi-devs/dev-1/v-dev = "0:0:1:0"
+ * Wait for <domid>/<vhost>/state + <domid>/<vhost>/vscsi-devs/dev-1/state become 4
+ *
+ * To remove a device from a vhost:
+ * <domid>/<vhost>/state = "7"
+ * <domid>/<vhost>/vscsi-devs/dev-1/state = "5"
+ * Wait for <domid>/<vhost>/state to become 4
+ * Wait for <domid>/<vhost>/vscsi-devs/dev-1/state become 6
+ * Remove <domid>/<vhost>/vscsi-devs/dev-1/{state,p-dev,v-dev,p-devname}
+ * Remove <domid>/<vhost>/vscsi-devs/dev-1/
+ *
+ */
+
/* Requests from the frontend to the backend */
/*
next prev parent reply other threads:[~2016-02-23 11:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-23 11:26 [PATCH v9 0/6] libxl: add support for pvscsi, iteration 9 Olaf Hering
2016-02-23 11:26 ` [PATCH v9 1/6] libxl: Export libxl__device_nextid for internal use Olaf Hering
2016-03-02 15:21 ` Wei Liu
2016-02-23 11:26 ` [PATCH v9 2/6] vscsiif.h: fix WWN notation for p-dev property Olaf Hering
2016-02-23 11:26 ` [PATCH v9 3/6] docs: add vscsi to xenstore-paths.markdown Olaf Hering
2016-02-23 11:26 ` Olaf Hering [this message]
2016-02-23 11:27 ` [PATCH v9 5/6] libxl: add support for vscsi Olaf Hering
2016-02-23 11:27 ` [PATCH v9 6/6] Scripts to create and delete xen-scsiback nodes in Linux target framework Olaf Hering
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