Re: Windows XP crash: emulation failed but !mmio_needed?

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Adam Monsen wrote:
> I had just installed a Windows XP guest and left it running for a few
> hours with no users logged in. The machine appears to have crashed.
> Avi requested that I send this bug(?) report to kvm-devel, so here
> 'tis...
>
> REPRO STEPS:
> 1. Install Fedora 7
> 2. Install KVM
> 3. Install Windows XP Professional in a guest
> 8GB disk space (on-disk file)
> 500MB RAM
> network is bridged to host's network
> 4. Implement the "Windows ACPI Workaround" as described on kvm.sf.net wiki
> 5. "Activate" Windows
> 6. Let box sit there for a few hours
>
> EXPECTED RESULT:
> guest continues to run happily
>
> ACTUAL RESULT:
> box crashed. Syslog has the following entry: "emulation failed but
> !mmio_needed? rip e05d e6 0d e6 da"
>   

The virtual machine has spontaneously rebooted, then failed because 
Windows has (legitimately) overwritten the real-mode task state segment 
located at the end of memory.  The emulation failure is for an 'out' 
instruction, which will trap if the tss is not set up correctly.

The emulation failure can be fixed by re-initializing the tss, or, even 
better, moving it beyond RAM, or by fully emulating real mode, but this 
doesn't say anything about the cause of the reboot.  Is there anything 
in the Windows event log (accessible using eventvwr.exe?)


-- 
error compiling committee.c: too many arguments to function


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