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Date: Mon, 30 May 2011 18:16:23 +0300
From: "Nadav Har'El" <nyh@math.technion.ac.il>
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Subject: Re: [Qemu-devel] drop -enable-nesting
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: john cooper <john.cooper@redhat.com>, "Roedel,
	Joerg" <Joerg.Roedel@amd.com>, Anthony Liguori <aliguori@us.ibm.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>

On Mon, May 30, 2011, Jan Kiszka wrote about "Re: drop -enable-nesting":
> > "-enable-nesting" could remain as a synonym for enabling either VMX or SVM
> > in the guest, depending on what was available in the host (because KVM now
> > supports both nested SVM and nested VMX, but not SVM-on-VMX or vice versa).
> 
> Why? Once nesting is stable (I think SVM already is), there is no reason
> for an explicit enable. And you can always mask it out via -cpu.

As far as I understand (and this was previously discussed on the QEMU mailing
list), the default emulated CPU does not include the "vmx" capability, and you
need to enable it with something like "-cpu qemu64,+vmx" (or "-cpu host").

I am not sure if it does enable the "svm" capability. If it does, it isn't
useful when KVM is enabled and the underlying host has VMX, not SVM.

Nadav.

-- 
Nadav Har'El                        |       Monday, May 30 2011, 27 Iyyar 5771
nyh@math.technion.ac.il             |-----------------------------------------
Phone +972-523-790466, ICQ 13349191 |Why do we drive on a parkway and park on
http://nadav.harel.org.il           |a driveway?