Re: [Xen-devel] guest state on realmode emulation failure

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 17/11/08 15:55, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

>>> As a secondary thing, I can't really see how emulation of a real-mode far
>>> return could ever fail with the register state given.
>> 
>> Have you tested with xen-unstable changeset 18766?
> 
> Not yet, but shouldn't that affect things only when 'mis-'using real mode
> (e.g. by leaving a 32-bit default operand size set)?

No, realmode_deliver_exception() was testing a potentially uninitialised
field. It's a nasty little bug that thus occasionally, whether real mode is
abused or not, causes you to write through ESP rather than SP.

 -- Keir



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