Re: [PATCH v2 3/4] arm64: dts: Add mediatek MT8173 SoC and evaluation board dts and Makefile

From: Marc Zyngier
Date: Mon Dec 22 2014 - 04:07:41 EST


On 20/12/14 20:07, Arnd Bergmann wrote:
> On Wednesday 17 December 2014 15:01:29 Marc Zyngier wrote:
>>
>> Indeed, as described in the documentation:
>> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0471b/CHDIFAEE.html
>>
>> Also it is worth noticing that given how GICV is placed, it will never
>> work with 64K pages and virtualization. Pretty sad.
>
> Does this mean no VGIC support on this platform so you have to emulate it
> in order to run virtual machines with 64K pages, or does it mean that
> it's impossible to use that way because you can't emulate it?

As Peter said, this is not a configuration we're willing to support:
- we don't have a API to tell userspace emulation about interrupts
generated by the generic timers
- we could move the whole GIC emulation into the kernel (at the moment,
only the distributor is there), but that would be a complete nightmare

It really looks like a case of "let's drop a bunch of 64bit cores into
an existing SoC". Shame people can't read integration guidelines...

M.
--
Jazz is not dead. It just smells funny...
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