Re: [Qemu-devel] [PATCH v5 10/12] hw/mips: malta: Add KVM support

Aurelien Jarno
2014-06-20T11:19:54Z

On Fri, Jun 20, 2014 at 12:38:30PM +0200, Paolo Bonzini wrote:
> Il 20/06/2014 11:10, Aurelien Jarno ha scritto:
> >> My idea was to add a machines-specific option umkernel=on, and require it
> >> in order to run KVM. Later we can add umkernel=on support for TCG as well,
> >> while umkernel=off with KVM requires virtualization extensions.
> >>
> >> The same option can disable pflash boot.
> >>
> >> What do you think?
> >
> >For what I understand the current KVM support in MIPS uses trap and
> >emulate and thus doesn't need hardware support, just a recent kernel
> >with the option enabled.
>
> Yes, but work to support virtualization extensions is underway.
> Patches were posted a few months ago.
>
> >That's why I do wonder if there is a real point
> >in supporting UM kernels in TCG mode.
>
> Debugging, mainly. It is sometimes useful to compare TCG with KVM
> on x86, and I suppose it could be the same on MIPS.

Ok, then we can indeed add a umkernel option, which is always enabled
with KVM, and which disable the flash (and why not other devices) in
that case.

At some point it might be a good idea to add a specific machine for
emulation/virtualization, like it is done on ARM, which do not have to
handle this kind of devices, and which does not have all the current
limitations of the Malta board.

--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurelien@aurel32.net http://www.aurel32.net