[edk2-devel] [PATCH 3/3] OvmfPkg/PlatformPei: Mark TPM MMIO range as unencrypted for SEV
Andrew Fish via groups.io
afish=apple.com at groups.io
Wed Apr 21 14:09:26 UTC 2021
https://edk2-docs.gitbook.io/edk-ii-build-specification/2_design_discussion/23_boot_sequence
> On Apr 20, 2021, at 11:34 PM, Eric van Tassell <evantass at amd.com> wrote:
>
>
>
>> On 4/20/21 5:54 PM, Tom Lendacky wrote:
>> From: Tom Lendacky <thomas.lendacky at amd.com>
>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3345
>> The TPM support in OVMF performs MMIO accesses during the PEI phase. At
>
> where are the phases defined and how many other are there?
>
>> this point, MMIO ranges have not been marked un-encyrpted, so an SEV-ES
>> guest will fail attempting to perform MMIO to an encrypted address.
>> Read the PcdTpmBaseAddress and mark the specification defined range
>> (0x5000 in length) as un-encrypted, to allow an SEV-ES guest to process
>> the MMIO requests.
>> Cc: Laszlo Ersek <lersek at redhat.com>
>> 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: James Bottomley <jejb at linux.ibm.com>
>> Cc: Jiewen Yao <jiewen.yao at intel.com>
>> Cc: Min Xu <min.m.xu at intel.com>
>> Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
>> ---
>> OvmfPkg/PlatformPei/PlatformPei.inf | 1 +
>> OvmfPkg/PlatformPei/AmdSev.c | 19 +++++++++++++++++++
>> 2 files changed, 20 insertions(+)
>> diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf b/OvmfPkg/PlatformPei/PlatformPei.inf
>> index 6ef77ba7bb21..de60332e9390 100644
>> --- a/OvmfPkg/PlatformPei/PlatformPei.inf
>> +++ b/OvmfPkg/PlatformPei/PlatformPei.inf
>> @@ -113,6 +113,7 @@ [Pcd]
>> [FixedPcd]
>> gEfiMdePkgTokenSpaceGuid.PcdPciExpressBaseAddress
>> + gEfiSecurityPkgTokenSpaceGuid.PcdTpmBaseAddress
>> gEmbeddedTokenSpaceGuid.PcdMemoryTypeEfiACPIMemoryNVS
>> gEmbeddedTokenSpaceGuid.PcdMemoryTypeEfiACPIReclaimMemory
>> gEmbeddedTokenSpaceGuid.PcdMemoryTypeEfiReservedMemoryType
>> diff --git a/OvmfPkg/PlatformPei/AmdSev.c b/OvmfPkg/PlatformPei/AmdSev.c
>> index dddffdebda4b..d524929f9e10 100644
>> --- a/OvmfPkg/PlatformPei/AmdSev.c
>> +++ b/OvmfPkg/PlatformPei/AmdSev.c
>> @@ -141,6 +141,7 @@ AmdSevInitialize (
>> )
>> {
>> UINT64 EncryptionMask;
>> + UINT64 TpmBaseAddress;
>> RETURN_STATUS PcdStatus;
>> //
>> @@ -206,6 +207,24 @@ AmdSevInitialize (
>> }
>> }
>> + //
>> + // PEI TPM support will perform MMIO accesses, be sure this range is not
>> + // marked encrypted.
>> + //
>> + TpmBaseAddress = PcdGet64 (PcdTpmBaseAddress);
>> + if (TpmBaseAddress != 0) {
>> + RETURN_STATUS DecryptStatus;
>> +
>> + DecryptStatus = MemEncryptSevClearPageEncMask (
>> + 0,
>> + TpmBaseAddress,
>> + EFI_SIZE_TO_PAGES (0x5000),
>> + FALSE
>> + );
>> +
>> + ASSERT_RETURN_ERROR (DecryptStatus);
>> + }
>> +
>> //
>> // Check and perform SEV-ES initialization if required.
>> //
>
>
>
>
>
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