tree bf73f1e6b944c190441413cedfb49b05e04ffe6b
parent f694010185c429629ad5a65245da08103e611852
author Jan Beulich <jbeulich@novell.com> 1205154677 +0000
committer Ingo Molnar <mingo@elte.hu> 1208446858 +0200

x86: prevent unconditional writes to DebugCtl MSR

Otherwise, enabling (or better, subsequent disabling) of single
stepping would cause a kernel oops on CPUs not having this MSR.

The patch could have been added a conditional to the MSR write in
user_disable_single_step(), but centralizing the updates seems safer
and (looking forward) better manageable.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Markus Metzger <markus.t.metzger@intel.com>

Signed-off-by: Ingo Molnar <mingo@elte.hu>