Re: [Question] About GET LBA STATUS(16) support in qemu scsi emulation layer

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Sun, Mar 01, 2020 at 01:01:29PM +0000, Lin Ma wrote:
> Hi all,
> 
> I'm not familiar with scsi, I'm curious why there is no GET LBA STATUS(16) support in qemu scsi emulation layer.
> 
> So far, There is only one subcommand of SERVICE ACTION was implemented: The READ CAPACITY(16)
> e.g.
> static int32_t scsi_disk_emulate_command(SCSIRequest *req, uint8_t *buf)
>     [......]
>     case SERVICE_ACTION_IN_16:
>         /* Service Action In subcommands. */
>         if ((req->cmd.buf[1] & 31) == SAI_READ_CAPACITY_16) {
>             [......]
>         }
>         trace_scsi_disk_emulate_command_SAI_unsupported();
>         goto illegal_request;
>     [......]
> 
> 
> It seems that this situation has been for a long time. Is the GET LBA STATUS (16 or 32) unnessesary for qemu scsi emulation or did I misunderstand something?

GET LBA STATUS is optional according to the SBC specification so QEMU's
SCSI target is conformant.

I guess the question is which applications need this command?

It's probably a case of no one needing this command enough to implement
it yet.

Stefan

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