Re: [Qemu-devel] drop -enable-nesting

[Roedel, Joerg]

On Mon, May 30, 2011 at 11:04:02AM -0400, Jan Kiszka wrote:
> On 2011-05-30 16:38, Nadav Har'El wrote:
> > On Mon, May 30, 2011, Jan Kiszka wrote about "drop -enable-nesting (was: 
> > [PATCH 3/7] cpu model bug fixes and definition corrections...)":
> >> On 2011-05-30 10:18, Roedel, Joerg wrote:
> >>> On Sat, May 28, 2011 at 04:39:13AM -0400, Jan Kiszka wrote:
> >>>
> >>>> J�rg, how to deal with -enable-nesting in qemu-kvm to align behavior
> >>>> with upstream?
> >>>
> >>> My personal preference is to just remove it. In upstream-qemu it is
> >>> enabled/disabled by +/-svm. -enable-nesting is just a historic thing
> >>> which can be wiped out.
> > 
> > "-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.
> 
> BTW, what are the defaults for SVM right now in qemu-kvm and upstream?
> Enable if the modeled CPU supports it?

qemu-kvm still needs -enable-nesting, otherwise it is disabled. Upstream
qemu should enable it unconditionally (can be disabled with -cpu ,-svm).

        Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632