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Re: [Minios-devel] [UNIKRAFT PATCHv4 21/43] plat/kvm: Add Arm64 basic entry code

Hi Wei,

On 20/07/2018 08:16, Wei Chen wrote:
        - What is the state of the memory at that time? You probably want to
follow what Image says: "The address range corresponding to the loaded
kernel image must be cleaned to PoC".

At the very beginning, I assume QEMU had help me sync the image memory to PoU
at least. Because guest will read image bypass the cache.

IHMO Point of Unification is far too weak for booting in a VM. This only tells you that the instruction cache, data cache, translation walks will have the same view. You don't know if the result has reached the memory and may not see it when MMU and cache is disabled. You want Point of Coherency here.

Anyway, in both case, you have to be careful when writing with MMU and cache off. So I would expect the boot code to contain cache maintenance in the next version.


Julien Grall

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