On 05/12/2016 01:20 PM, Tom Lendacky wrote:
> On 05/10/2016 08:57 AM, Borislav Petkov wrote:
>> On Tue, May 10, 2016 at 02:43:58PM +0100, Matt Fleming wrote:
>>> Is it not possible to maintain some kind of kernel virtual address
>>> mapping so memremap*() and friends can figure out when to twiddle the
>>> mapping attributes and map with/without encryption?
>>
>> I guess we can move the sme_* specific stuff one indirection layer
>> below, i.e., in the *memremap() routines so that callers don't have to
>> care... That should keep the churn down...
>>
>
> We could do that, but we'll have to generate that list of addresses so
> that it can be checked against the range being mapped. Since this is
> part of early memmap support searching that list every time might not be
> too bad. I'll have to look into that and see what that looks like.
I looked into this and this would be a large change also to parse tables
and build lists. It occurred to me that this could all be taken care of
if the early_memremap calls were changed to early_ioremap calls. Looking
in the git log I see that they were originally early_ioremap calls but
were changed to early_memremap calls with this commit:
commit abc93f8eb6e4 ("efi: Use early_mem*() instead of early_io*()")
Looking at the early_memremap code and the early_ioremap code they both
call __early_ioremap so I don't see how this change makes any
difference (especially since FIXMAP_PAGE_NORMAL and FIXMAP_PAGE_IO are
identical in this case).
Is it safe to change these back to early_ioremap calls (at least on
x86)?
Thanks,
Tom
>
> Thanks,
> Tom
>
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