[U-Boot] [RFC PATCH 0/6] ARMv7: Add HYP mode switching support

[Peter Maydell]

On 26 April 2013 14:24, Andre Przywara <andre.przywara at linaro.org> wrote:
> On 04/26/2013 03:18 PM, Peter Maydell wrote:
>> The obvious question here is "why do we need a new command?".
>> The kernel booting specification says "boot the kernel in
>> Hyp mode" so we should just always do that for booting Linux,
>> surely?

> Because it avoids regressions. I kind of feel uneasy to do a lot of
> tinkering with secure state and the GIC unconditionally, especially if
> enabled on many boards with virt-capable CPUs.

There aren't exactly very many of those out there, so if we
default to "boot in HYP mode" then (a) KVM will just work
out of the box and (b) people doing u-boot ports to their
board will find any issues and be able to submit fixes.
If we don't turn it on by default then we'll end up stuck
in a world where KVM doesn't work on half the virt capable
boards out there.

I have no objection to a "turn this off" escape hatch if
you think it's useful.

-- PMM