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List:       bochs-dev
Subject:    Re: [Bochs-developers] QNX 6 on Bochs 2.2
From:       Colin Burgess <colin.burgess () gmail ! com>
Date:       2005-06-22 12:56:38
Message-ID: f93f965050622055630b41eb8 () mail ! gmail ! com
[Download RAW message or body]

But it's only an exception when we try to do a task switch with an limit < 67H
We don't actually ever switch tasks the intel way.  Boch's is faulting
on the ltr
instruction, which specifically (according to the ia32 sdm) does not
perform a task switch.
Nor does it list #TS as a possible exception.

Boch's also faults when checking for IO access. Well since we don't
have an IO map (the tr.limit does not contain the IO bitmap base) then
it should check based on IOPL
only.

We may be doing things in a weird way, but it does work on real
hardware and on vmware.

On 6/9/05, Paul Brook <paul@codesourcery.com> wrote:
> On Thursday 09 June 2005 19:19, Colin Burgess wrote:
> > I have QNX 6.3.0 running on Bochs 2.2
> >
> > However Bochs is complaining that the 386TSS tr.limit is < 103
> >
> > We don't use an IO array, thus our TSS is only 100 bytes long.
> 
> This is an bug in QNX. The ia32 SDM says an invalid TSS exception is raised
> when it encounters "TSS segment limit less than 67H for 32-bit TSS".
> These last 4 bytes don't just control the IO array, they also contain the
> debug trap(T) bit.
> 
> Paul
> 


-- 
colin.burgess@gmail.com


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