Dne 25. 04. 22 v 7:51 Arthur Heymans napsal(a):
> 4MB IGD stolen memory is fine for 2M alignment on TSEG, so only dropping 1M 
> would be needed.

Yeah but TSEG can have 8MB and will require 8MB alignment (however I don't know 
if this setting is used in coreboot).

Petr

> Also that value goes up to 64MB, not 8M, but it's not documented in the 
> official documentation.
> 
> Kind regards,
> Arthur
> 
> On Sun, Apr 24, 2022 at 11:54 PM Petr Cvek <petrcve...@gmail.com 
> <mailto:petrcve...@gmail.com>> wrote:
> 
>     Thanks! I would never find the SMRR feature.
> 
>     Hmm that means 4MB stolen memory should be dropped along 1MB (TSEG can up 
> to 8MB on i945). Or alternatively to check if TSEG >= UMA in cmos 
> configuration. I suppose cmos.layout would need to support some kind of 
> scripting though.
> 
>     Petr
> 
>     Dne 24. 04. 22 v 18:56 Arthur Heymans napsal(a):
>     > Hi
>     >
>     > You want to align tseg for when smrr is supported by the CPU. I would 
> just drop support for 1MB stolen memory.
>     >
>     > Arthur
>     >
>     > On Sun, 24 Apr 2022, 05:40 Petr Cvek, <petrcve...@gmail.com 
> <mailto:petrcve...@gmail.com> <mailto:petrcve...@gmail.com 
> <mailto:petrcve...@gmail.com>>> wrote:
>     >
>     >     Hello,
>     >
>     >     On i945 northbridge:
>     >
>     >             ASSERTION ERROR: file 'src/cpu/x86/smm/tseg_region.c', line 
> 31
>     >
>     >     can be triggered by some configurations. The assert
>     >
>     >             ASSERT(IS_ALIGNED(sub_base, sub_size));
>     >
>     >     tests alignment of SMM base with SMM size. The problem is that IGD 
> stolen memory can offset the SMM base by a smaller size than the SMM size. 
> This causes SMM base to be unaligned. For example:
>     >
>     >     80000000: 2 GiB Top of RAM, stored in TOLUD
>     >     7ff00000: 1 MiB Stolen IGD RAM base, address in BSM
>     >     7fd00000: 2 MiB SMM base, defined as SMM size in ESMRAMC
>     >
>     >     -> 0x7fd00000 is not aligned to SMM size. Probably works for 
> different settings too.
>     >
>     >     RFC: should the assert from
>     >
>     >             
> https://elixir.bootlin.com/coreboot/4.16/source/src/cpu/x86/smm/tseg_region.c#L31
>  
> <https://elixir.bootlin.com/coreboot/4.16/source/src/cpu/x86/smm/tseg_region.c#L31>
>  
> <https://elixir.bootlin.com/coreboot/4.16/source/src/cpu/x86/smm/tseg_region.c#L31
>  
> <https://elixir.bootlin.com/coreboot/4.16/source/src/cpu/x86/smm/tseg_region.c#L31>>
>     >
>     >     be removed, changed or ignored on i945? The correct test should be 
> probably for 1 MiB alignement as the base of stolen IGD memory have [31:20] 
> bits. But I understand the smm_subregion() test is a generic one.
>     >
>     >     regards,
>     >     Petr
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