Re: [PATCH 0/2] kvm: disable virtualization on kdump

From: Eduardo Habkost <ehabkost@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@osdl.org>,
	kvm@vger.kernel.org, kexec@lists.infradead.org,
	Haren Myneni <hbabu@us.ibm.com>,
	Simon Horman <horms@verge.net.au>, Avi Kivity <avi@redhat.com>,
	Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH 0/2] kvm: disable virtualization on kdump
Date: Mon, 27 Oct 2008 13:50:03 -0200	[thread overview]
Message-ID: <20081027155003.GM23893@blackpad> (raw)
In-Reply-To: <m1skqi9iy9.fsf@frodo.ebiederm.org>

On Mon, Oct 27, 2008 at 08:05:50AM -0700, Eric W. Biederman wrote:
> Avi Kivity <avi@redhat.com> writes:
> 
> > There's no way to query whether vmx is enabled or disabled, AFAICT.  So we have
> > to execute vmxoff and ignore possible #UDs.
> >
> > If we trust the exception handlers, there's no problem.  Otherwise we need to
> > replace the current #UD handler with an iret (perhaps switching temporarily to
> > another IDT).
> 
> Ugh.  We already change the IDT on that code path so that
> may be a way to go.

I don't see the IDT being changed on native_machine_shutdown(). It even
uses notifier chain registration (register_die_notifier()) to sneak a
NMI handler in.

-- 
Eduardo

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec