On 05/27/21 01:11, Brijesh Singh wrote:
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
>
> When AMD SEV is enabled in the guest VM, a hypervisor need to insert a
> secrets page.
For pure SEV?
>
> When SEV-SNP is enabled, the secrets page contains the VM platform
> communication keys. The guest BIOS and OS can use this key to communicate
> with the SEV firmware to get attesation report. See the SEV-SNP firmware
> spec for more details for the content of the secrets page.
>
> When SEV and SEV-ES is enabled, the secrets page contains the information
> provided by the guest owner after the attestation. See the SEV
> LAUNCH_SECRET command for more details.
>
> Cc: James Bottomley <j...@linux.ibm.com>
> Cc: Min Xu <min.m...@intel.com>
> Cc: Jiewen Yao <jiewen....@intel.com>
> Cc: Tom Lendacky <thomas.lenda...@amd.com>
> Cc: Jordan Justen <jordan.l.jus...@intel.com>
> Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Cc: Erdem Aktas <erdemak...@google.com>
> Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
> ---
> OvmfPkg/OvmfPkgX64.dsc | 2 ++
> OvmfPkg/OvmfPkgX64.fdf | 5 +++++
> OvmfPkg/AmdSev/SecretPei/SecretPei.inf | 1 +
> OvmfPkg/AmdSev/SecretPei/SecretPei.c | 15 ++++++++++++++-
> 4 files changed, 22 insertions(+), 1 deletion(-)
How is all of the above related to the "OvmfPkg/OvmfPkgX64.dsc"
platform, where remote attestation is not a goal?
What you describe makes sense to me, but only for the remote-attested
"OvmfPkg/AmdSev/AmdSevX64.dsc" platform. (Which already includes
SecretPei and SecretDxe, and sets the necessary PCDs.)
Then, even if we limit this patch only to the "OvmfPkg/AmdSev/SecretPei"
module, the commit message does not explain sufficiently why the secrets
page must be reserved for good. The "SEV-SNP firmware spec" reference is
vague at best; I'm permanently lost between the dozen PDF files I have
downloaded locally from the AMD website. Please include a specific
document number, revision number, and chapter/section identifier.
Honestly I'm getting a *rushed* vibe on this whole series. Why is that?
Assume that I'm dumb. You won't be far from the truth. Then hold my hand
through all this?
Laszlo
>
> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
> index 999738dc39cd..ea08e1fabc65 100644
> --- a/OvmfPkg/OvmfPkgX64.dsc
> +++ b/OvmfPkg/OvmfPkgX64.dsc
> @@ -716,6 +716,7 @@ [Components]
> OvmfPkg/SmmAccess/SmmAccessPei.inf
> !endif
> UefiCpuPkg/CpuMpPei/CpuMpPei.inf
> + OvmfPkg/AmdSev/SecretPei/SecretPei.inf
>
> !if $(TPM_ENABLE) == TRUE
> OvmfPkg/Tcg/TpmMmioSevDecryptPei/TpmMmioSevDecryptPei.inf
> @@ -966,6 +967,7 @@ [Components]
> OvmfPkg/PlatformDxe/Platform.inf
> OvmfPkg/AmdSevDxe/AmdSevDxe.inf
> OvmfPkg/IoMmuDxe/IoMmuDxe.inf
> + OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf
>
> !if $(SMM_REQUIRE) == TRUE
> OvmfPkg/SmmAccess/SmmAccess2Dxe.inf
> diff --git a/OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf
> index d6be798fcadd..9126b8eb5014 100644
> --- a/OvmfPkg/OvmfPkgX64.fdf
> +++ b/OvmfPkg/OvmfPkgX64.fdf
> @@ -88,6 +88,9 @@ [FD.MEMFD]
> 0x00C000|0x001000
>
> gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupSize
>
> +0x00D000|0x001000
> +gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase|gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize
> +
> 0x010000|0x010000
>
> gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize
>
> @@ -179,6 +182,7 @@ [FV.PEIFV]
> INF SecurityPkg/Tcg/TcgPei/TcgPei.inf
> INF SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.inf
> !endif
> +INF OvmfPkg/AmdSev/SecretPei/SecretPei.inf
>
>
> ################################################################################
>
> @@ -314,6 +318,7 @@ [FV.DXEFV]
> INF ShellPkg/Application/Shell/Shell.inf
>
> INF MdeModulePkg/Logo/LogoDxe.inf
> +INF OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf
>
> #
> # Network modules
> diff --git a/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> b/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> index 08be156c4bc0..9265f8adee12 100644
> --- a/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> +++ b/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> @@ -26,6 +26,7 @@ [LibraryClasses]
> HobLib
> PeimEntryPoint
> PcdLib
> + MemEncryptSevLib
>
> [FixedPcd]
> gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase
> diff --git a/OvmfPkg/AmdSev/SecretPei/SecretPei.c
> b/OvmfPkg/AmdSev/SecretPei/SecretPei.c
> index ad491515dd5d..51eb094555aa 100644
> --- a/OvmfPkg/AmdSev/SecretPei/SecretPei.c
> +++ b/OvmfPkg/AmdSev/SecretPei/SecretPei.c
> @@ -7,6 +7,7 @@
> #include <PiPei.h>
> #include <Library/HobLib.h>
> #include <Library/PcdLib.h>
> +#include <Library/MemEncryptSevLib.h>
>
> EFI_STATUS
> EFIAPI
> @@ -15,10 +16,22 @@ InitializeSecretPei (
> IN CONST EFI_PEI_SERVICES **PeiServices
> )
> {
> + UINTN Type;
> +
> + //
> + // The location of the secret page should be marked reserved so that guest
> OS
> + // does not treated as a system RAM.
> + //
> + if (MemEncryptSevSnpIsEnabled ()) {
> + Type = EfiReservedMemoryType;
> + } else {
> + Type = EfiBootServicesData;
> + }
> +
> BuildMemoryAllocationHob (
> PcdGet32 (PcdSevLaunchSecretBase),
> PcdGet32 (PcdSevLaunchSecretSize),
> - EfiBootServicesData
> + Type
> );
>
> return EFI_SUCCESS;
>
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