Re: [edk2-devel] [PATCH 08/10] OvmfPkg/ResetVector: wire up 5-level paging for TDX

["Laszlo Ersek" <lersek@redhat.com>]

On 2/22/24 12:54, Gerd Hoffmann wrote:
> BSP workflow is quite simliar to the non-coco case.
> 
> TDX_WORK_AREA_PGTBL_READY is used to record the paging mode:
>   1 == 4-level paging
>   2 == 5-level paging
> 
> APs will look at TDX_WORK_AREA_PGTBL_READY to figure whenever
> they should enable 5-level paging or not.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  OvmfPkg/ResetVector/Ia32/IntelTdx.asm     | 13 ++++++++++++-
>  OvmfPkg/ResetVector/Ia32/PageTables64.asm | 12 ++++++++++++
>  2 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/OvmfPkg/ResetVector/Ia32/IntelTdx.asm b/OvmfPkg/ResetVector/Ia32/IntelTdx.asm
> index c6b86019dfb9..7d775591a05b 100644
> --- a/OvmfPkg/ResetVector/Ia32/IntelTdx.asm
> +++ b/OvmfPkg/ResetVector/Ia32/IntelTdx.asm
> @@ -179,7 +179,7 @@ InitTdx:
>  ;
>  ; Modified:  EAX, EDX
>  ;
> -; 0-NonTdx, 1-TdxBsp, 2-TdxAps
> +; 0-NonTdx, 1-TdxBsp, 2-TdxAps, 3-TdxAps5Level
>  ;
>  CheckTdxFeaturesBeforeBuildPagetables:
>      xor     eax, eax
> @@ -200,6 +200,17 @@ TdxPostBuildPageTables:
>      mov     byte[TDX_WORK_AREA_PGTBL_READY], 1
>      OneTimeCallRet TdxPostBuildPageTables
>  
> +%if PG_5_LEVEL
> +
> +;
> +; Set byte[TDX_WORK_AREA_PGTBL_READY] to 2
> +;
> +TdxPostBuildPageTables5Level:
> +    mov     byte[TDX_WORK_AREA_PGTBL_READY], 2
> +    OneTimeCallRet TdxPostBuildPageTables5Level
> +
> +%endif
> +
>  ;
>  ; Check if TDX is enabled
>  ;
> diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> index d736db028277..ada3dc0ffbe0 100644
> --- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> +++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> @@ -44,6 +44,7 @@ BITS    32
>  
>  %define TDX_BSP         1
>  %define TDX_AP          2
> +%define TDX_AP_5_LEVEL  3
>  
>  ;
>  ; For OVMF, build some initial page tables at
> @@ -214,6 +215,10 @@ SetCr3ForPageTables64:
>      je        TdxBspInit
>      cmp       eax, TDX_AP
>      je        SetCr3
> +%if PG_5_LEVEL
> +    cmp       eax, TDX_AP_5_LEVEL
> +    je        SetCr3La57
> +%endif
>  
>      ; Check whether the SEV is active and populate the SevEsWorkArea
>      OneTimeCall   CheckSevFeatures
> @@ -252,6 +257,13 @@ TdxBspInit:
>      ; TDX BSP workflow
>      ;
>      ClearOvmfPageTables
> +%if PG_5_LEVEL
> +    Check5LevelPaging Tdx4Level
> +    CreatePageTables5Level 0
> +    OneTimeCall TdxPostBuildPageTables5Level
> +    jmp SetCr3La57
> +Tdx4Level:
> +%endif
>      CreatePageTables4Level 0
>      OneTimeCall TdxPostBuildPageTables
>      jmp SetCr3

With SetCr3La57 eliminated as I request under patch #6, this patch looks
fine to me.

Thanks
Laszlo



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