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Date: Mon, 30 Aug 2021 09:03:39 +0200
From: "Gerd Hoffmann" <kraxel@redhat.com>
To: Min Xu <min.m.xu@intel.com>
Cc: devel@edk2.groups.io, Ard Biesheuvel <ardb+tianocore@kernel.org>,
	Jordan Justen <jordan.l.justen@intel.com>,
	Brijesh Singh <brijesh.singh@amd.com>,
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	James Bottomley <jejb@linux.ibm.com>,
	Jiewen Yao <jiewen.yao@intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH V5 1/2] OvmfPkg: Introduce Tdx BFV/CFV PCDs and PcdOvmfImageSizeInKb
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  Hi,

> In practice BFV is the code part of Ovmf image. CFV is the vars part of
> Ovmf image (exclude the SPARE part).

Why do you exclude the spare part?

>>From a security point of view I don't think it is a good idea to hard
code any assumptions about the layout of the vars volume.

> +SET gUefiOvmfPkgTokenSpaceGuid.PcdCfvBase           = $(FW_BASE_ADDRESS)
> +SET gUefiOvmfPkgTokenSpaceGuid.PcdCfvRawDataOffset  = $(VARS_OFFSET)
> +SET gUefiOvmfPkgTokenSpaceGuid.PcdCfvRawDataSize    = $(VARS_LIVE_SIZE)

I'd suggest to use $(VARS_SIZE) here.

take care,
  Gerd