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Date: Fri, 28 May 2010 15:32:53 +0200
From: "Roedel, Joerg" <Joerg.Roedel@amd.com>
Subject: Re: [Qemu-devel] Re: SVM emulation: EVENTINJ marked valid when a
	pagefault happens while issuing a software interrupt
Message-ID: <20100528133252.GA22539@amd.com>
References: <4BFE8F13.2000009@cs.vu.nl> <4BFEBF9E.90600@web.de>
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To: Jamie Lokier <jamie@shareable.org>
Cc: Erik van der Kouwe <vdkouwe@cs.vu.nl>, Jan Kiszka <jan.kiszka@web.de>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Gleb Natapov <gleb@redhat.com>

On Fri, May 28, 2010 at 09:20:31AM -0400, Jamie Lokier wrote:
> Roedel, Joerg wrote:
> > On Fri, May 28, 2010 at 02:10:59AM -0400, Jan Kiszka wrote:
> > > Erik van der Kouwe wrote:
> > 
> > > > In my experience, if I provide the -enable-kvm switch then the guest VMM
> > > > never detects the presence of virtualization support. Does this only
> > > > work on AMD hardware? Or do I need to supply some additional parameter
> > > > to make it work?
> > > 
> > > Yes, forgot to mention: -enable-nesting, and you need qemu-kvm. This
> > > feature hasn't been merged upstream yet.
> > 
> > And the svm-emulation is only available on AMD hardware.
> 
> I assume you mean nested SVM emulation in a KVM guest is only
> available on real AMD hardware?

Right.

> Is this due to something inherent, or just a limitation of the KVM
> code not handling all the necessary traps in kvm-intel?

The SVM and VMX extensions are architecturally very different in many
details. This makes it very hard to emulate VMX on SVM or vice verca. I
am not even sure if it is possible at all to emulate one extension in an
architectural complete way using the other extension.

	Joerg