Re: [Qemu-discuss] Setting vendor and product ids to emulated USB storage device

[Peter Maydell]

On Sun, 24 Sept 2023 at 23:05, Igor Ordecha <igor.ordecha@gmail.com> wrote:
> I'm trying to emulate a USB thumb drive from a .img file. My current 
> arguments for that look like this:
>
> -drive file=/path/to/file.img,if=none,id=drive-usb0,format=raw -device 
> nec-usb-xhci,id=xhci -device 
> usb-storage,bus=xhci.0,id=drive-usb0,drive=drive-usb0,removable=on,serial=0123456789abcdef
>
> It works but the device shows up as 46f4:0001 (vendor="QEMU", product="QEMU 
> USB HARDDRIVE") which my guest really doesn't like. Is there a way to change 
> the vendor id and product id? I looked everywhere, the manpage, forums, I 
> even asked ChatGPT in desperation(which surprisingly kinda worked. It told me 
> about the "serial" parameter which I also needed to spoof.), nothing.
>
> All I found was an email on this mailing list: 
> https://lists.nongnu.org/archive/html/qemu-discuss/2015-07/msg00072.html  (I 
> don't know how to properly link a thread, this is my first time using a 
> mailing list, sorry)
> It contains a hacky(as described by the author themself) patch to take vid 
> and pid but it's from 2015 and uses "-usbdevice disk" which is deprecated, I 
> believe.
>
> Is there a way to set vid and pid in current versions of QEMU or do I need to 
> adjust that patch to "-drive usb-storage" myself?

No, I don't think there is any way to set these -- they're
in a bit of fixed C code:
https://gitlab.com/qemu-project/qemu/-/blob/master/hw/usb/dev-storage.c?ref_type=heads#L165

(The right place to provide a command line override is
probably similar to serial=, as a bus property defined
in the list in hw/usb/bus.c which then affects the behaviour
of the code in hw/usb/desc.c. But I'm not very familiar with
the USB subsystem.)

What is this guest which doesn't like it? I would have
expected that since every random USB stick is going to
be from a different vendor that any guest that checks
for specific values here would not work on a lot of
real-world hardware...

thanks
-- PMM