[PATCH 1/1] QEMU: support USB cdrom devices

Jan-Marek Glogowski glogow at fbihome.de
Tue Sep 8 13:57:01 UTC 2020


Am 08.09.20 um 08:07 schrieb Gerd Hoffmann:
>>>> Also "info usb" just shows a single device. I just copied these lines
>>>> from a normal libvirt SCSI setup with two cdroms.
>>> That is normal, it actually is only one usb device after all ;)
>> I was referring to the posted usb-bot example, where "your" docs
>> (<qemu>/docs/usb-storage.txt) says it supports multiple LUNs, so I was
>> wondering, how these would be exposed on the USB bus.
> You can't see that on the USB bus.  usb-bot/usb-storage is a scsi host
> adapter, with some limitations (only one target, 15 luns max and luns
> can't be sparse).  You just have to set the LUN in the scsi commands to
> address the device you want.
>> All fine. I've spent my time on this. I just want to fix my LibreOffice
>> Windows Arm64 cross-build and need an install to debug my obviously
>> existing errors, but the current Windows installer ISOs even break
>> somewhere in the initial ramdisk setup in QEMU and the older versions
>> have timeouts, if current uup-based images are even correctly generated
>> on Linux, which I have no way to verify.
> FYI; You can simply copy all the files from the iso to a (virtual) usb
> stick and use that to boot the windows installer.

The problem is not using an USB stick or an USB CDROM. The old ISO from
1909 (18363.959) boots for me, but 2004 (19041.450) doesn't, generated
with the linux tools from uupdump.ml. For debugging I once modified the
BCD to get a menu with longer timeout and that shows up just fine.
Something breaks later, when the installer prepares the ramdisk ...
would be my guess. And I have no real knowledge how to proceed any
further with this.

And there are still all the OOBE timeouts / errors (like OOBEKEYBOARD),
which I get when the setup process runs at first start, after the
installer has finished. Very seldomly it works, most times it doesn't.
The only solution the Internet provides, is to try again, until it
doesn't happen; that is not practical with my x86_64 notebook hardware.
It's too slow and happens almost always for unknown reasons.

>From my POV the best seems to be to get some AArch64 HW, like a RasPi 4.
That seems to be able to run Windows Arm64 via KVM, from all I can tell
reading about it.

After getting a LibreOffice bug report for an Windows Arm64 build,
reading about Windows Arm64 in QEMU in years old blog posts, I just
thought I would fix the Windows cross build fallout and in the end do a
"quick" Windows install, check and fix my LibreOffice test program for
LO's UNO bridge and be done with it... then reality happened.

ATB and thanks for the comments,


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