[Qemu-discuss] Emulating DOS with passthrough SCSI access?

[Dmitry Brant]

Hello,

I'd like to use QEMU to emulate an MS-DOS system that will run a very
specific proprietary software that needs to talk to a (real) SCSI tape
drive.

I see that QEMU can offer passthrough access to the host SCSI bus, and it
looks like it can also emulate a SCSI adapter that the guest OS can use
(dc390). The problem is that I'm not sure how to tie all of this together.
I've tried the following command line:

qemu-system-i386 -m 32 -drive file="dosdrive.img",format=raw \
-drive id=tapedrive,if=none,format=raw,readonly=off,file=/dev/sg3 \
-device virtio-scsi-pci,id=scsi0 \
-device scsi-generic,bus=scsi0.0,drive=tapedrive \
-device dc390

...where /dev/sg3 is my actual SCSI device. But this causes the guest DOS
to hang while loading the ASPI driver, and nothing else happens.
Is what I'm trying to do in fact possible? And if so, can someone suggest
the proper parameters?


Best,

-- 
Dmitry Brant
https://dmitrybrant.com