Re: [Xen-devel] Doamin crash when trying to install disk encryption (PointSec) on Windows HVM

[Tom Rotenberg <tom.rotenberg@xxxxxxxxx>]

About the TR, i have re-checked it, and it seems like the TR value is still 0x58, althoug the LTR operation put 0x50 into it. Since, i looked at the LTR code you sent me, and it seems ok, i tend to suspect, that there was some kind of (hardware) task switch, which changed the TR value without me knowing, is it possible? because otherwise, i can't really explain why the TR value is different than what was loaded from the LTR operation...

BTW - how can i track what was the previous VMEXIT before this last VMENTRY which caused the exception? i think, that probably the last VMEXIT caused the "change" to vm86 mode, and this is waht causes the problem...

Tom

2009/4/23 Keir Fraser <keir.fraser@xxxxxxxxxxxxx>

On 23/04/2009 12:44, "Tom Rotenberg" <tom.rotenberg@xxxxxxxxx> wrote:

> However, from the VMCS dump, i saw data, which doesn't seem compatible with
> this, as the LDTR sellector is indeed 0, but has attributes and limit
> different from zero (although it should have been totaly disabled, by the
> LLDT, no?).

The 'unused' flag in the attributes word is set (bit 16) so LDTR is okay.

> And more important, the TR selector is 0x58, although from the LTR, it was
> supposed to be 0x50, no?

If 0x50 was loaded then the selector should certainly be 0x50.

 -- Keir

> (of-course it's possible that there were other instructions who changed it
> back, however, i am wondering if there is a problem here).

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