XP ACPI Uniprocessor HAL crash on v4.3.0

[pt58]

I have several WinXPSP3 VMs configured with 1 CPU and I/O APIC enabled so that they are detected in XP as ACPI Uniprocessor (rather than ACPI). These worked perfectly up to V4.2.18 On updating to 4.3.0 I get BSOD during bootup or while running at some random point. XP Vm's configured as ACPI (1CPU & no I/O APIC) or ACPI Multiprocessor (2 CPUs & I/O APIC) seem to run fine. Win7 VMs running using the same Uniprocessor settings also appear fine on v4.3.0

My host system is Win7x64. I gather that the VT-x code has been extensively re-written so I'm assuming a bug has crept in which is causing this issue.

[pt58]

Vbox logfile after BSOD

[Frank Mehnert]

Please could you also attach a VBox.log file when running the same VM with VBox 4.2.18? Thank you!

[pt58]

Same XP VM running fine on 4.2.18

[Ramshankar Venkataraman]

Duplicate of #12227.