graphic: 0.859 permissions: 0.842 boot: 0.817 device: 0.801 network: 0.799 architecture: 0.788 semantic: 0.762 ppc: 0.662 performance: 0.655 mistranslation: 0.644 register: 0.618 socket: 0.613 i386: 0.540 vnc: 0.516 debug: 0.487 peripherals: 0.465 kernel: 0.461 KVM: 0.461 PID: 0.450 files: 0.418 user-level: 0.394 virtual: 0.387 arm: 0.380 hypervisor: 0.373 risc-v: 0.372 VMM: 0.286 x86: 0.279 TCG: 0.277 assembly: 0.181 Unable to run OS/2 Warp4.52 Description of problem: Operating system crashes upon boot. Steps to reproduce: 1. Install OS/2 Warp4 2. Apply Fixpack15 3. Try to boot the system Additional information: This is a very old bug that seems to render a whole family of Operating Systems (OS/2 Warp4 and eComStation) unusable under Qemu. Warp4 works, in the sense that it does install and run, but just until it is updated to 4.52 (which is necessary to get a useable guest) I found traces of its existence as far as: https://bugs.launchpad.net/qemu/+bug/1743441 https://lists.gnu.org/archive/html/qemu-devel/2019-02/msg02337.html And i found the issue brieffly commented at https://www.os2world.com/forum/index.php?topic=2346.0 I quote: 'Regarding QEMU/KVM, OS/2 runs in QEMU mostly fine. Except the trap in os2lvm.dmd and non-working netbeui.os2 and tcpbeui.os2. The problem with os2lvm.dmd is because QEMU closely follows the intel spec, which is incorrect. The spec says that 16-bit SGDT instruction behaves the same like in i286 processor. But it's not true, it behaves like i386 instruction. So, QEMU emulates SGDT 16-bit instruction incorrectly. OS2LVM.DMD uses 16-bit SGDT instruction and it hits the problem.' After a brief discussion on the Warp4 group at groups.io where I was told that this is indeed a Qemu bug, I thought someone has to report on that.