Re: [PULL 4/5] hw/ufs: Support for UFS logical unit

[Paolo Bonzini]

On 9/15/23 00:19, Jeuk Kim wrote:
> First, ufs-lu has a feature called "unit descriptor". This feature shows 
> the status of the ufs-lu
>
> and only works with UFS-specific "query request" commands, not SCSI 
> commands.

This looks like something that can be implemented in the UFS subsystem.

> UFS also has something called a well-known lu. Unlike typical SCSI 
> devices, where each lu is independent,
> UFS can control other lu's through the well-known lu.

This can also be implemented in UfsBus.

> Finally, UFS-LU will have features that SCSI-HD does not have, such as 
> the zone block command.

These should be implemented in scsi-hd as well.

> In addition to this, I wanted some scsi commands to behave differently 
> from scsi-hd, for example,
> the Inquiry command should read "QEMU UFS" instead of "QEMU HARDDISK",
> and the mode_sense_page command should have a different result.

Some of these don't have much justification, and others (such as the 
control page) could be done in scsi-hd as well.

We should look into cleaning this up and making ufs-lu share a lot more 
code with scsi-hd; possibly even supporting -device scsi-hd with UFS 
devices.  I am not going to ask you for a revert, but if this is not 
done before 8.2 is out, I will ask you to disable it by default in 
hw/ufs/Kconfig.

In the future, please Cc the SCSI maintainers for UFS patches.

Paolo