Re: [PATCH 1/2] Platforms/AMD/Styx: limit VA space to 40 bits

[Leif Lindholm <leif.lindholm@linaro.org>]

On Fri, Sep 09, 2016 at 09:15:38AM +0100, Ard Biesheuvel wrote:
> We can cover the entire MMIO range and 512 GB of memory starting at
> 0x80_0000_0000 using 40 bits of VA space, both in the page tables and
> in the GCD memory map.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

> ---
>  Platforms/AMD/Styx/CelloBoard/CelloBoard.dsc         | 5 +++++
>  Platforms/AMD/Styx/OverdriveBoard/OverdriveBoard.dsc | 5 +++++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/Platforms/AMD/Styx/CelloBoard/CelloBoard.dsc b/Platforms/AMD/Styx/CelloBoard/CelloBoard.dsc
> index 8a100e0d9a3c..0a987cc3b118 100644
> --- a/Platforms/AMD/Styx/CelloBoard/CelloBoard.dsc
> +++ b/Platforms/AMD/Styx/CelloBoard/CelloBoard.dsc
> @@ -375,6 +375,11 @@ DEFINE DO_KCS    = 0
>    # Size of the region used by UEFI in permanent memory (Reserved 64MB)
>    gArmPlatformTokenSpaceGuid.PcdSystemMemoryUefiRegionSize|0x04000000
>  
> +  # 40 bits of VA space is sufficient to support up to 512 GB of RAM in the
> +  # range 0x80_0000_0000 - 0xFF_FFFF_FFFF (all platform and PCI MMIO is below
> +  # that)
> +  gEmbeddedTokenSpaceGuid.PcdPrePiCpuMemorySize|40
> +
>    #
>    # ARM PrimeCell
>    #
> diff --git a/Platforms/AMD/Styx/OverdriveBoard/OverdriveBoard.dsc b/Platforms/AMD/Styx/OverdriveBoard/OverdriveBoard.dsc
> index 38c3309dcff1..72ceb8b6994e 100644
> --- a/Platforms/AMD/Styx/OverdriveBoard/OverdriveBoard.dsc
> +++ b/Platforms/AMD/Styx/OverdriveBoard/OverdriveBoard.dsc
> @@ -382,6 +382,11 @@ DEFINE DO_KCS       = 1
>    # Size of the region used by UEFI in permanent memory (Reserved 64MB)
>    gArmPlatformTokenSpaceGuid.PcdSystemMemoryUefiRegionSize|0x04000000
>  
> +  # 40 bits of VA space is sufficient to support up to 512 GB of RAM in the
> +  # range 0x80_0000_0000 - 0xFF_FFFF_FFFF (all platform and PCI MMIO is below
> +  # that)
> +  gEmbeddedTokenSpaceGuid.PcdPrePiCpuMemorySize|40
> +
>    #
>    # ARM PrimeCell
>    #
> -- 
> 2.7.4
>