Re: [PATCH 08/36] AArch64: Kernel booting and initialisation

From: Arnd Bergmann
Date: Fri Jul 20 2012 - 04:28:17 EST

On Friday 20 July 2012, Jon Masters wrote:
> > I think it would be best to list the technical limitations, from the
> > kernel's perspective, of the unsupported exception levels and the
> > advantages of the supported exception levels here. If you want to guide
> > system builders towards EL2, I think it'd be more convincing to document
> > the relevant technical aspects (perhaps KVM needs facilities only
> > available in EL2) than just providing an unexplained requirement.
> Unless you enter at EL2 you can never install a hypervisor. That's the
> reason for the requirement for generally entering at EL2 when possible.

How do nested hypervisors work in this scenario? Does the first-level
hypervisor (counting from most priviledged) provide a guest that starts
in an emulated EL2 state, or is this done differently?

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