Block Device: Legacy SCSI 'cmd' Framing Requirements

Regarding  Version 1.1 draft 01

 

When using Block-device, legacy scsi commands, while 
VIRTIO_F_ANY_LAYOUT is negotiated, it is not clear if ‘cmd’ field must reside in a single, separate device-readable buffer.

In Section 5.2.6.3 it is written, in general (without reference to
VIRTIO_F_ANY_LAYOUT) that 
‘cmd’ field must reside in a single buffer.

Section 5.2.6.4, 2nd bullet describes framing requirements for SCSI commands, but does not refer to ‘cmd’ field.

 

I suggest adding description of ‘cmd’ field  framing requirement in this bullet, as well.

 

 

 

Excerpts:

 

Section 5.2.6.3 (Legacy Interface: Device Operation):

“The cmd field is only present for scsi packet command requests, and indicates the command to perform.

This field MUST reside in a single, separate device-readable buffer;”

 

Section 5.2.6.4 (Legacy Interface: Framing Requirements):

“For SCSI commands there are additional constraints. errors, data_len, sense_len and residual MUST

reside in a single, separate device-writable descriptor, sense MUST reside in a single separate devicewritable

descriptor of size 96 bytes, and errors, data_len, sense_len and residual MUST reside a single

separate device-writable descriptor.”

 

 

Thanks

Gil Savir

 

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