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Date: Wed, 26 Jan 2022 13:06:01 +0100
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>,
	Erdem Aktas <erdemaktas@google.com>,
	James Bottomley <jejb@linux.ibm.com>,
	Jiewen Yao <jiewen.yao@intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH V5 18/33] OvmfPkg: Check Tdx in QemuFwCfgPei to avoid DMA operation
Message-ID: <20220126120601.bcrv4zajivhbbggv@sirius.home.kraxel.org>
References: <cover.1642899774.git.min.m.xu@intel.com>
 <37a90fcfe15738c0b6e0edba59b6db48dc36681c.1642899774.git.min.m.xu@intel.com>
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  Hi,

> +BOOLEAN
> +QemuFwCfgIsTdxGuest (
> +  VOID
> +  )
> +{
> +  CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER  *CcWorkAreaHeader;
> +
> +  CcWorkAreaHeader = (CONFIDENTIAL_COMPUTING_WORK_AREA_HEADER *)FixedPcdGet32 (PcdOvmfWorkAreaBase);
> +  return (CcWorkAreaHeader != NULL && CcWorkAreaHeader->GuestType == GUEST_TYPE_INTEL_TDX);
> +}

I think once the "SEV BaseMemEncryptLib cleanup" series by Brijesh is
merged it should be possible to use CcWorkAreaHeader->GuestType to
detect both sev and tdx and simplify the code here a bit.

take care,
  Gerd