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

[Jan Kiszka]

On 2011-05-30 17:16, Nadav Har'El wrote:
> 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").

qemu64 is an artificial AMD model. Adding VMX to it may have interesting
effects on the guests. Better use host or a recent Intel model.

> 
> 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.

That's what KVM is supposed to filter based on the host's capabilities.
I bet it does already.

Jan

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