[Qemu-devel] successes and failures with QEMU so far

[Kyle Hayes]

The current (at least as of Friday) CVS version of QEMU builds OK for 
me (apart from user error).  I am testing whole system emulation at 
this point.  I am running QEMU on an up to date Gentoo system with a 
HT address@hidden, and 512MB of DDR400 RAM.  Because of the hyperthreading 
processor, this looks like a SMP system.

I only build the x86 targets and only use the soft MMU as I am running 
unchanged x86 OSes.

Various Linux distributions seem to be working quite well.  Every so 
often, something will hang, but I haven't seen that problem for a few 
days.  The performance varies.  Some X Window operations seem to take 
a long time and other things are fast.  Is that generally a function 
of the translated code size?  For instance, running KDE in Mepis in 
QEMU shows some odd delays with opening the "K" menu.  Even though 
most things are fast, the K menu takes a few seconds to show up when 
I click on the icon for it.  Opening Open Office is horribly slow.  
It is at least 20x slower than opening it natively on my P4.  It 
takes several minutes to show a final window.  Again, is this a 
translated code cache size effect?

However, I'd like to be able to run Windows 98 or Windows ME (XP would 
be fine, but that might be harder) in a QEMU instance.  

I made a blank 2GB disk image in a file.  I placed a WinME 
installation CD in the CDROM drive and started QEMU:

qemu -hda win.img -cdrom /dev/cdrom -m 256

I have the TUN device working and it gets set up correctly on the host 
system.

Windows will auto-start, but then goes into a text-mode with a command 
prompt.  Perhaps it is not finding any video card?  Linux/X seems to 
work.

At the prompt, I can run SETUP.EXE directly.  This results in the 
installer attempting to do a SCANDISK of the drive image.  Needless 
to say, that failed since the image is blank.  

So, I grabbed FreeDOS and used it to partition and format the blank 
disk image as FAT32.  I installed FreeDOS onto the disk image and 
booted it within QEMU to make sure it was all OK.  That worked fine.  
However, I found that I had to turn off XMS in FreeDOS.  If I left it 
on, it would fail on boot. I can't even remember whether that was 
extended memory or exanded memory.  My DOS days are far in the 
past :-)

After this, SETUP tries to run SCANDISK again and that stops with the 
complaint that something is wrong with a very, very high cluster 
number.  The number is so high that it is clear that it is not in the 
disk image at all.  I think something went wrong before that error 
shows.  The first part of SCANDISK checking works.

This is very repeatable for me.  I can give more details if needed.

Win98 doesn't even get to a command prompt.  It just dies with a 
complaint about a fault in the bios code.

I have not yet tried copying the WinME installation files to the disk 
image and running it directly from there.  

I would very much like to get Windows working so that I didn't need to 
use either VMWare or Win4Lin.  Both require somewhat invasive kernel 
patches and seem to degrade system stability.  QEMU will run without 
any kernel patches and thus can be used with stock kernels.  This is 
a very important feature for me.  I don't need raw speed, but I do 
need Windows for some things.

Has any one had any luck?  I'm going to try installing Windows on a 
small disk and then copy the image directly to a disk file and see if 
I can boot into that.  I can probably make a system with an NE2K card 
in it to simulate the QEMU environment somewhat.

"Why Windows?", you ask....

I am currently working with a group as a consultant installing systems 
for non-profit organizations.  These organizations have little money 
for things like VMWare and are often required to use certain Windows 
applications for city or state (local or regional) taxes and other 
reporting such as for mental health clinics.  QEMU (if Windows would 
work) would let them move most of their operations to Linux and keep 
only the few applications they need for legal reasons.  Saving these 
organizations money means that fewer mentally ill people have to 
wander the street (to give an example based on our current client).

If there are ways I can help by recreating these problems and 
recording any details let me know.  I am a programmer, but I don't 
know x86 instruction details well at all.

Best,
Kyle