From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [RFC][PATCH] KVM: nVMX: Leave VMX mode on apparent CPU reset
Date: Mon, 30 Dec 2013 18:02:17 -0200
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Cc: Gleb Natapov <gleb@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>, kvm <kvm@vger.kernel.org>
To: Jan Kiszka <jan.kiszka@siemens.com>
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On Mon, Dec 16, 2013 at 10:32:34AM +0100, Jan Kiszka wrote:
> As long as we do not expose all the VMX related states to user space,
> there is no way to properly reset a VCPU when VMX is enabled. Emulate
> this for now by catching host-side clearings of the feature control MSR.
> This allows to reboot a VM while it is running some hypervisor code.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
> 
> Better ideas? Or continue to leave it as it is?

The hidden backport might be problematic... How about an explicit 
notification to leave guest mode?
Such as a new flag to KVM_SET_REGS (or even a separate ioctl?).