Re: [PATCH 3/3] arm, arm64: KVM: handle potential incoherency of readonly memslots

Mario Smarduch
2014-11-20T19:15:57Z

On 11/20/2014 10:40 AM, Peter Maydell wrote:
> On 20 November 2014 18:35, Mario Smarduch <m.smarduch@samsung.com> wrote:
>> I think beyond consistency, there should be no double mappings with
>> conflicting attributes at any time or CPU state is undefined.
>
> The situation is not so bleak as this. See section B2.9 "Mismatched
> memory attributes" in the ARMv8 ARM ARM (DDI0487A.d), which lays
> out in some detail what the results of mismatched attributes are
> (generally, you lose ordering or coherency guarantees you might
> have hoped to have). They're not pretty, but it's not as bad
> as completely UNPREDICTABLE behaviour.
>
> thanks
> -- PMM
>
Hi Peter,
thanks for digging that up, quite a list to navigate
but it does provide detailed guidance.

- Mario