Re: [edk2-devel] [PATCH RFC v2 11/28] OvmfPkg: Reserve Secrets page in MEMFD

["Dov Murik" <dovmurik@linux.vnet.ibm.com>]

[+cc: Tobin]

Hi Brijesh,

On 30/04/2021 14:51, 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.
> 
> 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 <jejb@linux.ibm.com>
> Cc: Min Xu <min.m.xu@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Erdem Aktas <erdemaktas@google.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  OvmfPkg/AmdSev/SecretPei/SecretPei.c   | 16 +++++++++++++++-
>  OvmfPkg/AmdSev/SecretPei/SecretPei.inf |  1 +
>  OvmfPkg/OvmfPkgX64.dsc                 |  2 ++
>  OvmfPkg/OvmfPkgX64.fdf                 |  5 +++++
>  4 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/OvmfPkg/AmdSev/SecretPei/SecretPei.c b/OvmfPkg/AmdSev/SecretPei/SecretPei.c
> index ad491515dd..92836c562c 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 +16,23 @@ InitializeSecretPei (
>    IN CONST EFI_PEI_SERVICES     **PeiServices
>    )
>  {
> +  UINTN   Type;
> +
> +  //
> +  // The secret page should be mapped encrypted by the guest OS and must not
> +  // be treated as a system RAM. Mark it as ACPI NVS so that guest OS maps it
> +  // encrypted.
> +  //
> +  if (MemEncryptSevSnpIsEnabled ()) {
> +    Type = EfiACPIMemoryNVS;
> +  } else {
> +    Type = EfiBootServicesData;
> +  }
> +

Would it make sense to always use EfiACPIMemoryNVS for the injected secret area, even for regular SEV (non-SNP)?

-Dov



>    BuildMemoryAllocationHob (
>      PcdGet32 (PcdSevLaunchSecretBase),
>      PcdGet32 (PcdSevLaunchSecretSize),
> -    EfiBootServicesData
> +    Type
>      );
> 
>    return EFI_SUCCESS;
> diff --git a/OvmfPkg/AmdSev/SecretPei/SecretPei.inf b/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> index 08be156c4b..9265f8adee 100644
> --- a/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> +++ b/OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> @@ -26,6 +26,7 @@
>    HobLib
>    PeimEntryPoint
>    PcdLib
> +  MemEncryptSevLib
> 
>  [FixedPcd]
>    gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase
> diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
> index a7d747f6b4..593c0e69f6 100644
> --- a/OvmfPkg/OvmfPkgX64.dsc
> +++ b/OvmfPkg/OvmfPkgX64.dsc
> @@ -716,6 +716,7 @@
>    OvmfPkg/SmmAccess/SmmAccessPei.inf
>  !endif
>    UefiCpuPkg/CpuMpPei/CpuMpPei.inf
> +  OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> 
>  !if $(TPM_ENABLE) == TRUE
>    OvmfPkg/Tcg/Tcg2Config/Tcg2ConfigPei.inf
> @@ -965,6 +966,7 @@
>    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 d519f85328..b04175f77c 100644
> --- a/OvmfPkg/OvmfPkgX64.fdf
> +++ b/OvmfPkg/OvmfPkgX64.fdf
> @@ -88,6 +88,9 @@ gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase|gUefiCpuPkgTokenSpaceGuid.PcdSevE
>  0x00C000|0x001000
>  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupSize
> 
> +0x00D000|0x001000
> +gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase|gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize
> +
>  0x010000|0x010000
>  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize
> 
> @@ -178,6 +181,7 @@ INF  OvmfPkg/Tcg/Tcg2Config/Tcg2ConfigPei.inf
>  INF  SecurityPkg/Tcg/TcgPei/TcgPei.inf
>  INF  SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.inf
>  !endif
> +INF  OvmfPkg/AmdSev/SecretPei/SecretPei.inf
> 
>  ################################################################################
> 
> @@ -313,6 +317,7 @@ INF  OvmfPkg/LinuxInitrdDynamicShellCommand/LinuxInitrdDynamicShellCommand.inf
>  INF  ShellPkg/Application/Shell/Shell.inf
> 
>  INF MdeModulePkg/Logo/LogoDxe.inf
> +INF OvmfPkg/AmdSev/SecretDxe/SecretDxe.inf
> 
>  #
>  # Network modules
>