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

[Christoffer Dall]

On Fri, Apr 26, 2013 at 7:14 AM, Andre Przywara
<andre.przywara at linaro.org> wrote:
> On 04/26/2013 03:42 PM, Peter Maydell wrote:
>> 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.
>
> OK, that's a point. I changed the code already and will include it in
> the next revision.
>
I strongly agree with Peter, and in fact I think it should only be a
compile time option, not a run-time option, only for those debugging
u-boot and a kernel on some new platform.

-Christoffer