Re: [Xen-ia64-devel] [Patch] cleanup warning of UC|WB attributepage

[Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>]

Hi, Alex and all

>   Why does efi_ucwb() only check certain types of ranges for having
>both UC and WB attributes.  Seems like the types might be implementation
>specific.  I'm also a little concerned about scanning the EFI memory
>map, but I guess this is expected to be a rare event.  Is there an
>approach we could take to prevent these cases from happening (for a well
>behaved guest) rather than catching them at the end?  Thanks,
Exactly, I'll update the patch as efi_ucwb() don't check EFI Mermoy Type
if we choice this approch. And as you said, this case is rare. 
So this scanning should not affect performance.

BTW, I also thought another approch to prevent these case.
Because these memory area is accessed as both UC and WB,
we need to use new flag. 
(For example _PAGE_MA_UCE, I'm not sure we can use this flag for UC|WB.
or should we make new flag?)

In consideration of stability, I didn't make new flag.
(Because I must check many part of memory access.)
Which approch do you prefer? or another suggestion?

Best Regards,

Akio Takebe


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