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Re: [PATCH v5 1/6] x86/debugger: Remove debugger_trap_entry()


  • To: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Thu, 21 Apr 2022 15:02:26 +0200
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  • Cc: Bobby Eshleman <bobby.eshleman@xxxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>
  • Delivery-date: Thu, 21 Apr 2022 13:02:40 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 20.04.2022 16:13, Andrew Cooper wrote:
> From: Bobby Eshleman <bobby.eshleman@xxxxxxxxx>
> 
> debugger_trap_entry() is unrelated to the other contents of debugger.h.  It is
> a no-op for everything other than #DB/#BP, and for those it invokes guest
> debugging (CONFIG_GDBSX) not host debugging (CONFIG_CRASH_DEBUG).
> 
> Furthermore, the description of how to use debugger_trap_entry() is at best,
> stale.  It is not called from all exception paths,

But on almost all (before this change) - the exception looks to be
#NM.

> and because the developer
> is forced to modify Xen to perform debugging, editing debugger_trap_entry() is
> not the way one would efficiently go about diagnosing the problem.

Shouldn't it be the remote end to request which exceptions it wants
to be notified of? If so, removing the hook invocation isn't very
helpful.

Jan




 


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