Re: [PATCH V7 26/37] MdeModulePkg: Add PcdTdxSharedBitMask

["Wang, Jian J" <jian.j.wang@intel.com>]

Hi Min,

Similar to patch 25, I don't see the needs to make this PCD dynamic only.
Do you have any strong reasons? If not sure, maybe it'd be better to put
it under following section.

[PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]

Regards,
Jian

> -----Original Message-----
> From: Xu, Min M <min.m.xu@intel.com>
> Sent: Monday, February 28, 2022 3:21 PM
> To: devel@edk2.groups.io
> Cc: Xu, Min M <min.m.xu@intel.com>; Wang, Jian J <jian.j.wang@intel.com>;
> Wu, Hao A <hao.a.wu@intel.com>; Brijesh Singh <brijesh.singh@amd.com>;
> Aktas, Erdem <erdemaktas@google.com>; James Bottomley
> <jejb@linux.ibm.com>; Yao, Jiewen <jiewen.yao@intel.com>; Tom Lendacky
> <thomas.lendacky@amd.com>; Gerd Hoffmann <kraxel@redhat.com>
> Subject: [PATCH V7 26/37] MdeModulePkg: Add PcdTdxSharedBitMask
> 
> RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
> 
> Guest Physical Address (GPA) space in Td guest is divided into private
> and shared sub-spaces, determined by the SHARED bit of GPA. This PCD
> holds the shared bit mask. Its default value is 0 and it will be set
> in PlatformPei driver if it is of Td guest.
> 
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: Erdem Aktas <erdemaktas@google.com>
> Cc: James Bottomley <jejb@linux.ibm.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Min Xu <min.m.xu@intel.com>
> ---
>  MdeModulePkg/MdeModulePkg.dec | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/MdeModulePkg/MdeModulePkg.dec
> b/MdeModulePkg/MdeModulePkg.dec
> index 453f2a74b11d..e90a7f38708c 100644
> --- a/MdeModulePkg/MdeModulePkg.dec
> +++ b/MdeModulePkg/MdeModulePkg.dec
> @@ -2143,6 +2143,10 @@
>    # @Prompt The flag which indicates if IA32_EFER is allowed to be changed.
> 
> gEfiMdeModulePkgTokenSpaceGuid.PcdIa32EferChangeAllowed|TRUE|BOOLEA
> N|0x00030009
> 
> +  ## This PCD holds the shared bit mask for page table entries when Tdx is
> enabled.
> +  # @Prompt The shared bit mask when Intel Tdx is enabled.
> +
> gEfiMdeModulePkgTokenSpaceGuid.PcdTdxSharedBitMask|0x0|UINT64|0x000
> 3000a
> +
>  [PcdsDynamicEx]
>    ## This dynamic PCD enables the default variable setting.
>    #  Its value is the default store ID value. The default value is zero as Standard
> default.
> --
> 2.29.2.windows.2