From 5d5206bd9c04f71209730d7a2af3e69ce5e2ed43 Mon Sep 17 00:00:00 2001 From: pbonzini Date: Mon, 9 Jun 2014 13:18:11 +0000 Subject: virtio-scsi: support well-known logical units The REPORT LUNS well-known logical unit is useful because it lets you retrieve information about all targets with a single command. It also provides an easy way to send a no-op request. Signed-off-by: Paolo Bonzini git-svn-id: https://tools.oasis-open.org/version-control/svn/virtio@381 0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652 --- content.tex | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/content.tex b/content.tex index aa8f748..19f1c32 100644 --- a/content.tex +++ b/content.tex @@ -4600,13 +4600,18 @@ struct virtio_scsi_req_cmd { #define VIRTIO_SCSI_S_ACA 3 \end{lstlisting} -\field{lun} addresses a target and logical unit in the -virtio-scsi device's SCSI domain. The only supported format for -\field{lun} is: first byte set to 1, second byte set to target, -third and fourth byte representing a single level LUN structure, -followed by four zero bytes. With this representation, a -virtio-scsi device can serve up to 256 targets and 16384 LUNs per -target. +\field{lun} addresses the REPORT LUNS well-known logical unit, or +a target and logical unit in the virtio-scsi device's SCSI domain. +When used to address the REPORT LUNS logical unit, \field{lun} is 0xC1, +0x01 and six zero bytes. The virtio-scsi device SHOULD implement the +REPORT LUNS well-known logical unit. + +When used to address a target and logical unit, the only supported format +for \field{lun} is: first byte set to 1, second byte set to target, +third and fourth byte representing a single level LUN structure, followed +by four zero bytes. With this representation, a virtio-scsi device can +serve up to 256 targets and 16384 LUNs per target. The device MAY also +support having a well-known logical units in the third and fourth byte. \field{id} is the command identifier (``tag''). -- cgit v1.2.3