Proper DVD Emulation

[remlei]

As you may now, Vanilla WIndows ISOs does (windows 7 or later) does not work with gadget_cdrom, for some reason, once the windows iso boots up and goes to the GUI section, the cdrom suddenly goes poof out of existence, making the windows pe environment to install windows complaining for missing installation files. There's a workaround for it so OK I guess.

Fast forward today, people from pikvm finally able to handle DVD ISO and able to install windows from start to finish for using a Vanilla Windows ISO. Based on this issue they were able to achieve it.

I hope you can port the changes on pikvm to here.

[chrisirwin]

FWIW, the issue doesn't link to any commits.

The commits to pikvm's pikvm and kvmd projects are mostly just changing terms (CD-ROM -> CD/DVD) and adjusting warning messages:

• pikvm/pikvm@001dedd
• pikvm/kvmd@2acd613

The real magic seems to be a kernel patch applied to their 'packages' project (which makes sense, as this was a kernel limitation):

• pikvm/packages@3e56a4d

This may or may not apply cleanly to the kernel being used by gadget_cdrom. Additionally, I haven't researched the lineage of this patch. It may be written by pikvm themselves, as there doesn't seem to be any other attribution.

[mdevaev]

@chrisirwin Hello, I'm PiKVM dev. I saw the link to my Issue and decided to check that here :)

I wrote this patch myself based on few sources:

• Old early and incomplete proof-of-concept
• Rejected patchset from here
• This good patch (still incomplete and contains few bugs in handlers)
• Documentation for physical drive developers and also a bunch of MMC-2, MMC-3 and some other SCSI docs to add some magic values and missing operand handlers.

I tried to leave as many comments as possible to make it easier for people to follow me. I plan to bring this patch to the upstream, but we need to get rid of 0xff in SCSI parameter validation firstly and add some credits. I've been testing this implementation for a long time and it seems that it works in all important cases, I was even able to install windows on a mac mini using the official ISO.