From mboxrd@z Thu Jan  1 00:00:00 1970
From: George Dunlap <George.Dunlap@eu.citrix.com>
Subject: Re: I have used printk in some hypercall.But Dom0 can't
 be booted.
Date: Mon, 2 Apr 2012 10:00:50 +0100
Message-ID: <CAFLBxZa7fha+Hh2v7gY0Cgn8eGmnKhWQ2TCdBtp8wSb8v4kOCg@mail.gmail.com>
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To: SuperWong <wang_nets@163.com>
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On Sat, Mar 31, 2012 at 2:15 PM, SuperWong <wang_nets@163.com> wrote:
> Hi all:
> =A0 =A0I wanted to record some information about some hypercalls and trac=
e the
> hypercalls.So I have tried to add printk in the hypercall.But the Dom0 ca=
n't
> be *booted*.For example, I add printk at the beginning of do_set_trap_tab=
le.
> printk("<1>""HYPERCALL:do_set_trap_table");
> Why I can't add printk in hypercall?
> Does anyone know the reason and the solution?Thanks.

There's no way we can answer this question without the output of the
dom0 saying why it failed.

The best way to do this is to set up a serial console:
 http://wiki.xen.org/wiki/Xen_Serial_Console

 -George