[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 4/5] vscsiif.h: add some notes about xenstore layout
Signed-off-by: Olaf Hering <olaf@xxxxxxxxx> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx> Cc: Ian Campbell <ian.campbell@xxxxxxxxxx> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> Cc: Jan Beulich <jbeulich@xxxxxxxx> Cc: Keir Fraser <keir@xxxxxxx> Cc: Tim Deegan <tim@xxxxxxx> --- xen/include/public/io/vscsiif.h | 68 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/xen/include/public/io/vscsiif.h b/xen/include/public/io/vscsiif.h index e8e38a9..2c5f04a 100644 --- a/xen/include/public/io/vscsiif.h +++ b/xen/include/public/io/vscsiif.h @@ -104,6 +104,74 @@ * 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" + * + * + * 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 */ /* _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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