This patch is a workaround to not show pvpanic in UI to avoid the problem in Windows.
It's not a workaround, it is a proper bugfix.
What versions of Windows did you test it on? Did it hide the New Hardware wizard properly (I think it appears only on XP/2003)?
Windows XP. I didn't see hardware wizard, maybe it is because I tested the same VM before and XP remembered the device and wasn't boring to prompt again.
Tested in a freshly installed Windows XP, the device is hidden but the hardware wizard is shown.
Then unfortunately this patch alone is useless. :(
What would work is treat this as a 2000/XP bug and use _OSI to probe for Vista/2008 or later ("Windows 2006" and "Windows 2006.1", says drivers/acpi/acpica/utosi.c). Perhaps on top of this one.
Paolo