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From: "Nadav Har'El" <nyh@math.technion.ac.il>
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>
Subject: Re: [Qemu-devel] drop -enable-nesting
Date: Mon, 30 May 2011 18:16:23 +0300	[thread overview]
Message-ID: <20110530151623.GA3630@fermat.math.technion.ac.il> (raw)
In-Reply-To: <4DE3B1E2.7020006@siemens.com>

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?

  parent reply	other threads:[~2011-05-30 15:16 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-23 21:46 [Qemu-devel] [PATCH 3/7] cpu model bug fixes and definition corrections: Add kvm emulated x2apic flag to config defined cpu models john cooper
2011-05-28  8:39 ` Jan Kiszka
2011-05-30  8:18   ` Roedel, Joerg
2011-05-30 14:04     ` [Qemu-devel] drop -enable-nesting (was: [PATCH 3/7] cpu model bug fixes and definition corrections...) Jan Kiszka
2011-05-30 14:38       ` Nadav Har'El
2011-05-30 15:04         ` [Qemu-devel] drop -enable-nesting Jan Kiszka
2011-05-30 15:10           ` Roedel, Joerg
2011-05-30 15:15             ` Jan Kiszka
2011-05-30 15:19               ` Avi Kivity
2011-05-30 15:27                 ` Jan Kiszka
2011-05-30 15:42                   ` Jan Kiszka
2011-05-31  8:44                 ` Daniel P. Berrange
2011-05-31  8:58                   ` Avi Kivity
2011-05-31  9:06                     ` Roedel, Joerg
2011-05-31  9:15                     ` Paolo Bonzini
2011-05-31  9:16                       ` Avi Kivity
2011-05-30 15:16           ` Nadav Har'El [this message]
2011-05-30 15:59             ` Jan Kiszka

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