Can't run qemu-kvm with recent kernels in PAE mode

Can't run qemu-kvm with recent kernels in PAE mode

[Dan Higgins]

Hi KVM Gurus. I need some help with this problem that has existed for 
the past several kernel update releases. It used to work fine, probably 
back around kernel 2.6.33, but now I can't run any of my usual VM's in 
KVM with a PAE-enabled kernel.

WITH PAE enabled, and WITHOUT KVM enabled (by adding the -no-kvm 
option), VM's boot up fine and run, however very slowly as expected.

Or, WITHOUT PAE enabled, VM's boot up and run with or without KVM enabled.

The symptom has changed since my last kernel update, 2.6.36. AFTER 
2.6.33 but BEFORE 2.6.36, it looked like right after POST the screen 
would just stay black with a blinking text cursor at top-left, with CPU 
at 100%.

Now, with 2.6.36, on Windows XP SP2 32-bit I can see it say "Booting 
from Hard Disk..." then immediately it reboots.
On the QEMU Linux Test image (linux-0.2.img), right after "Uncompressing 
Linux..." immediately it reboots.

My system is Arch Linux with all latest updates as of this writing. I 
compiled my PAE kernel myself, which is from a trustworthy Arch 
repository, based on the vanilla non-PAE kernel that Arch provides, with 
only the CONFIG_HIGHMEM64G compile option turned on.

I know just running a 64-bit system would be nice, but this particular 
system has 32-bit images that it needs to run.

Hopefully my hardware isn't too weird. It's fairly new anyway. Here's info:

$ cat /proc/cpuinfo
processor    : 0
vendor_id    : AuthenticAMD
cpu family    : 16
model        : 6
model name    : AMD Turion(tm) II Dual-Core Mobile M500
stepping    : 2
cpu MHz        : 2194.355
cache size    : 512 KB
physical id    : 0
siblings    : 2
core id        : 0
cpu cores    : 2
apicid        : 0
initial apicid    : 0
fdiv_bug    : no
hlt_bug        : no
f00f_bug    : no
coma_bug    : no
fpu        : yes
fpu_exception    : yes
cpuid level    : 5
wp        : yes
flags        : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca 
cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt 
pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc nonstop_tsc extd_apicid 
pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm 
sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt npt lbrv svm_lock 
nrip_save
bogomips    : 4390.57
clflush size    : 64
cache_alignment    : 64
address sizes    : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

processor    : 1
vendor_id    : AuthenticAMD
cpu family    : 16
model        : 6
model name    : AMD Turion(tm) II Dual-Core Mobile M500
stepping    : 2
cpu MHz        : 2194.355
cache size    : 512 KB
physical id    : 0
siblings    : 2
core id        : 1
cpu cores    : 2
apicid        : 1
initial apicid    : 1
fdiv_bug    : no
hlt_bug        : no
f00f_bug    : no
coma_bug    : no
fpu        : yes
fpu_exception    : yes
cpuid level    : 5
wp        : yes
flags        : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca 
cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt 
pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc nonstop_tsc extd_apicid 
pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm 
sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt npt lbrv svm_lock 
nrip_save
bogomips    : 4390.69
clflush size    : 64
cache_alignment    : 64
address sizes    : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

$ pacman -Qi qemu-kvm
Name           : qemu-kvm
Version        : 0.13.0-1
URL            : http://www.linux-kvm.org
Licenses       : GPL2  LGPL2.1
Groups         : None
Provides       : qemu
Depends On     : libjpeg  libpng  libsasl  curl  sdl  alsa-lib  esound  
gnutls>=2.4.1  bluez  vde2  util-linux-ng
Optional Deps  : None
Required By    : qemu-launcher
Conflicts With : qemu
Replaces       : kvm
Installed Size : 6484.00 K
Packager       : Tobias Powalowski <tpowa@archlinux.org>
Architecture   : i686
Build Date     : Sun 31 Oct 2010 03:36:52 AM CDT
Install Date   : Sun 28 Nov 2010 02:39:39 AM CST
Install Reason : Explicitly installed
Install Script : Yes
Description    : Latest KVM QEMU is a generic and open source processor 
emulator which achieves a good emulation speed by using dynamic translation.

$ uname -a
Linux danbook.danamis.com 2.6.36-pae #1 SMP PREEMPT Sun Nov 28 01:08:27 
CST 2010 i686 AMD Turion(tm) II Dual-Core Mobile M500 AuthenticAMD GNU/Linux

$ pacman -Qi kernel26-pae
Name           : kernel26-pae
Version        : 2.6.36.1-3
URL            : http://www.kernel.org
Licenses       : GPL2
Groups         : base
Provides       : None
Depends On     : coreutils  linux-firmware  module-init-tools  
mkinitcpio>=0.5.20
Optional Deps  : crda: to set the correct wireless channels of your country
Required By    : None
Conflicts With : None
Replaces       : kernel24  kernel24-scsi  kernel26-scsi  alsa-driver  
ieee80211  hostap-driver26  pwc  nforce  squashfs  unionfs  ivtv  
zd1211  kvm-modules  iwlwifi
                  rt2x00-cvs  gspcav1  atl2  wlan-ng26  rt2500  nouveau-drm
Installed Size : 89760.00 K
Packager       : Dan Higgins <dan@danamis.com>
Architecture   : i686
Build Date     : Sun 28 Nov 2010 01:16:14 AM CST
Install Date   : Sun 28 Nov 2010 01:21:04 AM CST
Install Reason : Explicitly installed
Install Script : Yes
Description    : The Linux Kernel and modules with PAE support (HIGHMEM64G)

Command line that does NOT work:
qemu -m 1G -hda '/home/dan/tmp/linux-0.2.img'

As I mentioned before, adding "-no-kvm" to the above will work.

Let me know what is the best next step on this. Thanks very much in 
advance for any guidance.

Regards,
Dan