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Re: [Xen-devel] [PATCH] vmx: Fix single step on debugger

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] vmx: Fix single step on debugger
From: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
Date: Mon, 22 Dec 2008 11:34:09 +0900
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Indeed, this fix is hacky but it works well for me.

At first, I tried setting GUEST_PENDING_DBG_EXCEPTIONS.BS
according to the SDM. As a result, the guest doesn't be killed
but never go progress after the STI instruction
(i.e. VM exit immediately after VM entry) as long as RFLAGS.TF=1.
That is inconvenient for debugging. 

Is there any other way?

Thanks,
Kouya

Keir Fraser writes:
> On 19/12/2008 09:48, "Kouya Shimura" <kouya@xxxxxxxxxxxxxx> wrote:
> 
> > The hvm domain which is being debugged sometimes crashes with the
> > following message:
> 
> The fix looks like a dubious hack to me. Wouldn't it at least be a bit
> cleaner to mess with DR6.BS (the flag that's actually being checked by the
> CPU) rather than messing with the DEBUGCTL.BTF control flag?
> 
>  -- Keir
> 

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