[edk2-devel] [PATCH V4 2/3] OvmfPkg/Sec: Update the check logic in SevEsIsEnabled

[Brijesh Singh via groups.io]

Hi Min,

On 8/2/21 8:18 PM, Min Xu wrote:
> RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
> 
> SevEsIsEnabled return TRUE if SevEsWorkArea->SevEsEnabled is non-zero.
> It is correct when SevEsWorkArea is only used by SEV. After Intel TDX
> is enabled in Ovmf, the SevEsWorkArea is shared by TDX and SEV. (This
> is to avoid the waist of memory region in MEMFD). The value of
> SevEsWorkArea->SevEsEnabled now is :
>   0 if in Legacy guest
>   1 if in SEV
>   2 if in Tdx guest
> That's why the changes is made.
> 
> Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
> Cc: Jordan Justen <jordan.l.justen at intel.com>
> Cc: Brijesh Singh <brijesh.singh at amd.com>
> Cc: Erdem Aktas <erdemaktas at google.com>
> Cc: James Bottomley <jejb at linux.ibm.com>
> Cc: Jiewen Yao <jiewen.yao at intel.com>
> Cc: Tom Lendacky <thomas.lendacky at amd.com>
> Signed-off-by: Min Xu <min.m.xu at intel.com>
> ---
>   OvmfPkg/Sec/SecMain.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c
> index 9db67e17b2aa..e166a9389a1a 100644
> --- a/OvmfPkg/Sec/SecMain.c
> +++ b/OvmfPkg/Sec/SecMain.c
> @@ -828,7 +828,7 @@ SevEsIsEnabled (
>   
>     SevEsWorkArea = (SEC_SEV_ES_WORK_AREA *) FixedPcdGet32 (PcdSevEsWorkAreaBase);
>   
> -  return ((SevEsWorkArea != NULL) && (SevEsWorkArea->SevEsEnabled != 0));
> +  return ((SevEsWorkArea != NULL) && (SevEsWorkArea->SevEsEnabled == 1));
>   }

This is wrong, we need to check the SevEs sub type and not the global 
Sev enable. This also need to be broken into at least two commits

1. introduce the updated CcWorkArea structure
2. update the existing code to use the CcWorkArea layout

If you are okay then I can rework and send the patch so that you can add 
the TDX on top of it.

thanks

>   
>   VOID
> 


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