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[Xen-devel] Re: possible changes was Re: [PATCH] make domu_debug run-tim

To: Kip Macy <kmacy@xxxxxxxxxx>
Subject: [Xen-devel] Re: possible changes was Re: [PATCH] make domu_debug run-time option + fix int3 handling for MP
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Mon, 16 May 2005 21:10:08 +0100
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On 16 May 2005, at 20:07, Kip Macy wrote:

I can chunk this into 3 or 4 patches and make enabling domu_debug a separate
DOM0 operation. Would this be more palatable?

Not if I understand the purpose of this patch. As I understand it, the sole reason for making domu_debug configurable per-domain is to distinguish the cause of an 'int3' when you take an int3 trap. If a domain is a domu_debug domain then you assume that any int3 is for the domu debugger; otherwise, none are.

Apart from not being a very nice extension of the domain-building interface, I think the correct solution is to have a breakpoint-setting API within Xen that is shared by all of the debugger stubs. This would allow each debugger to set and clear breakpoints (i.e., add and remove int3 instructions), and would automatically demux int3 traps to the correct debugger(s), and/or propagate the trap up to the guest kernel if appropriate.

 -- Keir


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