[RFC PATCH 01/19] OvmfPkg: Reserve the Secrets and Cpuid page for the SEV-SNP guest

["Brijesh Singh" <brijesh.singh@amd.com>]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275

During the SEV-SNP guest launch sequence, two special pages need to
be inserted, the secrets page and cpuid page. The secrets page,
contain the VM platform communication keys. The guest BIOS and OS
can use this key to communicate with the SEV firmware to get the
attestation report. The Cpuid page, contain the CPUIDs entries
filtered through the AMD-SEV firmware.

The VMM will locate the secrets and cpuid page addresses through a
fixed GUID and pass them to SEV firmware to populate further.
For more information about the page content, see the SEV-SNP spec.

To simplify the pre-validation range calculation in the next patch,
the CPUID and Secrets pages are moved to the start of the
MEMFD_BASE_ADDRESS.

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>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 OvmfPkg/OvmfPkg.dec                          |  8 +++++++
 OvmfPkg/OvmfPkgX64.fdf                       | 24 ++++++++++++--------
 OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm | 19 ++++++++++++++++
 OvmfPkg/ResetVector/ResetVector.inf          |  4 ++++
 OvmfPkg/ResetVector/ResetVector.nasmb        |  2 ++
 5 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
index 4348bb45c6..062926772d 100644
--- a/OvmfPkg/OvmfPkg.dec
+++ b/OvmfPkg/OvmfPkg.dec
@@ -317,6 +317,14 @@
   gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretBase|0x0|UINT32|0x42
   gUefiOvmfPkgTokenSpaceGuid.PcdSevLaunchSecretSize|0x0|UINT32|0x43
 
+  ## The base address of the CPUID page used by SEV-SNP
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpCpuidBase|0|UINT32|0x48
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpCpuidSize|0|UINT32|0x49
+
+  ## The base address of the Secrets page used by SEV-SNP
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsBase|0|UINT32|0x50
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsSize|0|UINT32|0x51
+
 [PcdsDynamic, PcdsDynamicEx]
   gUefiOvmfPkgTokenSpaceGuid.PcdEmuVariableEvent|0|UINT64|2
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashVariablesEnable|FALSE|BOOLEAN|0x10
diff --git a/OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf
index d519f85328..ea214600be 100644
--- a/OvmfPkg/OvmfPkgX64.fdf
+++ b/OvmfPkg/OvmfPkgX64.fdf
@@ -67,27 +67,33 @@ ErasePolarity = 1
 BlockSize     = 0x10000
 NumBlocks     = 0xD0
 
-0x000000|0x006000
+0x000000|0x001000
+gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpCpuidBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpCpuidSize
+
+0x001000|0x001000
+gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsSize
+
+0x002000|0x006000
 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesSize
 
-0x006000|0x001000
+0x008000|0x001000
 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfLockBoxStorageBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfLockBoxStorageSize
 
-0x007000|0x001000
+0x009000|0x001000
 gEfiMdePkgTokenSpaceGuid.PcdGuidedExtractHandlerTableAddress|gUefiOvmfPkgTokenSpaceGuid.PcdGuidedExtractHandlerTableSize
 
-0x008000|0x001000
+0x00A000|0x001000
 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbPageTableBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbPageTableSize
 
-0x009000|0x002000
+0x00B000|0x002000
 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbSize
 
-0x00B000|0x001000
-gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase|gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize
-
-0x00C000|0x001000
+0x00D000|0x001000
 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBackupSize
 
+0x00F000|0x001000
+gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase|gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize
+
 0x010000|0x010000
 gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize
 
diff --git a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm
index 9c0b5853a4..5456f02924 100644
--- a/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm
+++ b/OvmfPkg/ResetVector/Ia16/ResetVectorVtf0.asm
@@ -47,6 +47,25 @@ TIMES (15 - ((guidedStructureEnd - guidedStructureStart + 15) % 16)) DB 0
 ;
 guidedStructureStart:
 
+;
+; SEV-SNP boot support
+;
+; sevSnpBlock:
+;   For the initial boot of SEV-SNP guest, a Secrets and CPUID page must be
+;   reserved by the BIOS at a RAM area defined by SEV_SNP_SECRETS_PAGE
+;   and SEV_SNP_CPUID_PAGE. A VMM will locate this information using the
+;   SEV-SNP boot block.
+;
+; GUID (SEV-SNP boot block): bd39c0c2-2f8e-4243-83e8-1b74cebcb7d9
+;
+sevSnpBootBlockStart:
+    DD      SEV_SNP_SECRETS_PAGE
+    DD      SEV_SNP_CPUID_PAGE
+    DW      sevSnpBootBlockEnd - sevSnpBootBlockStart
+    DB      0xC2, 0xC0, 0x39, 0xBD, 0x8e, 0x2F, 0x43, 0x42
+    DB      0x83, 0xE8, 0x1B, 0x74, 0xCE, 0xBC, 0xB7, 0xD9
+sevSnpBootBlockEnd:
+
 ;
 ; SEV Secret block
 ;
diff --git a/OvmfPkg/ResetVector/ResetVector.inf b/OvmfPkg/ResetVector/ResetVector.inf
index dc38f68919..d890bb6b29 100644
--- a/OvmfPkg/ResetVector/ResetVector.inf
+++ b/OvmfPkg/ResetVector/ResetVector.inf
@@ -37,6 +37,10 @@
   gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbSize
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpCpuidBase
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpCpuidSize
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsBase
+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSnpSecretsSize
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbPageTableBase
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecGhcbPageTableSize
   gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase
diff --git a/OvmfPkg/ResetVector/ResetVector.nasmb b/OvmfPkg/ResetVector/ResetVector.nasmb
index 5fbacaed5f..2c194958f4 100644
--- a/OvmfPkg/ResetVector/ResetVector.nasmb
+++ b/OvmfPkg/ResetVector/ResetVector.nasmb
@@ -75,6 +75,8 @@
   %define SEV_ES_WORK_AREA (FixedPcdGet32 (PcdSevEsWorkAreaBase))
   %define SEV_ES_WORK_AREA_RDRAND (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 8)
   %define SEV_ES_WORK_AREA_ENC_MASK (FixedPcdGet32 (PcdSevEsWorkAreaBase) + 16)
+  %define SEV_SNP_SECRETS_PAGE FixedPcdGet32 (PcdOvmfSnpSecretsBase)
+  %define SEV_SNP_CPUID_PAGE  FixedPcdGet32 (PcdOvmfSnpCpuidBase)
   %define SEV_ES_VC_TOP_OF_STACK (FixedPcdGet32 (PcdOvmfSecPeiTempRamBase) + FixedPcdGet32 (PcdOvmfSecPeiTempRamSize))
 %include "Ia32/Flat32ToFlat64.asm"
 %include "Ia32/PageTables64.asm"
-- 
2.17.1