Re: [Xen-devel] [PATCH 2/4] EFI/early: add /mapbs to map EfiBootServices{Code, Data}

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 10/06/15 20:48, Konrad Rzeszutek Wilk wrote:
> On Wed, Jun 10, 2015 at 07:12:07PM +0100, Andrew Cooper wrote:
>> On 10/06/15 18:22, Roy Franz wrote:
>>>>> I read it backwards and thought this was currently excluding them like
>>>>> x86 does.
>>>>>
>>>>> Am I correct that the stricter x86 behaviour is per the spec, and this
>>>>> new option is a workaround for non-compliant systems?
>>>> Yes.
>>>>
>>>>> If so unless Roy knows of a reason why these should be mapped on ARM be
>>>>> default (i.e. the ARM spec differs) I'd be inclined to suggesting the
>>>>> default be stricter on ARM too for consistency.
>>>> I agree, but would want this to be a separate patch then in any event.
>>>> I.e. I'm intending to commit the whole series shortly.
>>>>
>>>> Jan
>>>>
>>> The open question regarding the Arm code is whether we want/need this 
>>> workaround
>>> for Arm as well, right?  I don't see a reason why firmware bugs
>>> regarding memory allocation
>>> types would be x86 specific, so we could see firmware broken the same
>>> way on arm platforms.
>> It would be nice to hope that the arm side was all coded to spec. 
>> However, the realist in me would expect to see the same kinds of
>> mistakes on any architecture.
>>
>>> Is !map_bs the default?
>>>
>>> I think "reserve_bs" would be a better name, as I think of it as being
>>> 'mapped' when it is added
>>> as normal memory to the memory map.  I find the terminology in the
>>> patch a bit generic/confusing.
>> Technically, it is "map boot services code/data for runtime services",
>> as it is a workaround for firmware which doesn't correctly avoid using
>> __init/__initdata at runtime.
>>
>> I don't agree that "reserve_bs" is any better, but can't think of a 3rd
>> alternative which would be better than either.
>>
> fix_bs ?
>
> <chuckles>

:)

~Andrew

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