Re: [PATCH v3 16/16] xen/arm: arm64: Document Cortex-A57 erratum 834220

[Julien Grall <julien.grall@arm.com>]

Hi Stefano,

On 22/06/16 11:08, Stefano Stabellini wrote:
> On Tue, 7 Jun 2016, Julien Grall wrote:
>> The ARM erratum applies to certain revisions of Cortex-A57. The
>> processor may report a Stage 2 translation fault as the result of
>> Stage 1 fault for load crossing a page boundary when there is a
>> permission fault or device memory fault at stage 1 and a translation
>> fault at Stage 2.
>>
>> So Xen needs to check that Stage 1 translation does not generate a fault
>> before handling the Stage 2 fault. If it is a Stage 1 translation fault,
>> return to the guest to let the processor injecting the correct fault.
>                            ^let the process inject (let somebody do something)
>
>
>> Only document it as this is already the behavior of the fault handlers.
>> Note that some optimization could be done to avoid unnecessary translation
>> fault. This is because HPFAR_EL2 is valid for more use case. For the moment,
>> the code is left unmodified.
>>
>> Signed-off-by: Julien Grall <julien.grall@arm.com>
>
> Acked-by: Stefano Stabellini <sstabellini@kernel.org>

I have another series coming up which require to implement a workaround 
for the erratum.

Given this is only documentation, I am planning to drop this patch from 
the series.

Regards,

-- 
Julien Grall

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