[vbox-dev] How to really disable HWACC & Raw modes?

[Tom Birch]

I'm trying to get VBox running with as little dependency on the kernel
as possible, so no hardware acceleration, no raw mode, etc. everything
just running in QEMU. I'm running VBoxSDL because it supports explicit
arguments, and it seems to work. Running

VirtualBox.app/Contents/MacOS/VBoxSDL  --startvm Ubuntu --nohwvirtex
--norawr3 --norawr0

will load my Ubuntu VM fairly slowly (definitely slower than if I
don't specify --nohwvirtex), it gets up to Gnome, and the only calls
into R0 while it is running are VMMR0_DO_GVMM_SCHED_HALT and
VMMR0_DO_GVMM_SCHED_WAKE_UP (as shown by instrumenting
vmmR0EntryExWorker)

The problem is that VMMR0_DO_CALL_HYPERVISOR is called exactly once,
right after VMMR0_DO_VMMR0_INIT. This goes through all the switcher
code code that I'm trying to avoid. I don't understand why it's doing
this, and it seems to only happen once and have everything else
actually done up in userland by QEMU, any ideas?

cheers,
Tom