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[Xen-devel] Re: softirq change was Re: domu_debug support removed on mar

To: Kip Macy <kip.macy@xxxxxxxxx>
Subject: [Xen-devel] Re: softirq change was Re: domu_debug support removed on march 25th from traps.c in -unstable
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Wed, 13 Apr 2005 18:59:53 +0100
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 13 Apr 2005, at 18:48, Kip Macy wrote:

No idea why the trace trap flag isn't getting cleared? I can work at
around it at the application level but that is aesthetically
displeasing.

You mean that the TF bit is not cleared by the domu_debug code when it should be? The correct place to fix this is in include/asm-x86/debugger.h in debugger_trap_entry().

In general (not using domu_debug) it is not Xen's job to clear TF. We clear it when we 'bounce' the exception into the guest OS, but the saved application stack frame will include EFLAGS with the TF bit still set. This matches real hardware.

 -- Keir


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