So, refreshing it all again with more correct information. First, it appears that only 32bit version of qemu userspace is affected, and only when using 32bit version of guest. So far, either 64bit qemu userpace or 64bit windows7 guest is enough for the issue to not show up. Second, both win7 and winXP (32bit) are affected. Third, current qemu-kvm/master appears to be unaffected too.
The problem is that on first and all subsequent guest REBOOT (not first boot but really REBOOT) -- after the guest rebuilt its HAL I guess, due to some changes in "hardware" it noticed, -- the guest BSODs during boot with this code: STOP: 0x0000005C (0x000000000000010B, 0x0000000000000003, 0x000000000000000, 0x000000000000000) After painful bisection between 1.0 and current git, the result is this: First bad commit: commit 5b6fb069378e61c45c577bbec3d7ef60367f7e4c Author: Avi Kivity <a...@redhat.com> Date: Thu Mar 1 12:58:46 2012 +0200 pc-bios: update kvmvapic.bin Signed-off-by: Avi Kivity <a...@redhat.com> diff --git a/pc-bios/kvmvapic.bin b/pc-bios/kvmvapic.bin new file mode 100755 index 0000000..045f5c2 Binary files /dev/null and b/pc-bios/kvmvapic.bin differ Which, despite the name, actually INTRODUCES kvmvapic.bin, not merely updates it. So apparently this introduction of kvmvapic.bin resulted in autoloading implemented earlier to starte entering the game, which appears to be this one: commit e5ad936b0fd7dfd7fd7908be6f9f1ca88f63b96b Author: Jan Kiszka <jan.kis...@siemens.com> Date: Fri Feb 17 18:31:19 2012 +0100 kvmvapic: Introduce TPR access optimization for Windows guests And indeed, we're talking about windows guests here... Anything I can do further to debug/fix the issue? Thanks, /mjt