From e1c7f9b4e59e2df20650de3de98c2b2bc7879524 Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Wed, 2 Mar 2022 21:31:34 +0800
Subject: [PATCH] OvmfPkg: Generate CloudHv as a PVH ELF binary

Following the model from the Xen target, CloudHv is generated as a PVH
ELF binary to take advantage of the PVH specification, which requires
less emulation from the VMM.

The fdf include file CloudHvElfHeader.fdf.inc has been generated from
the following commands:

$ gcc -D PVH64 -o elf_gen OvmfPkg/OvmfXenElfHeaderGenerator.c
$ ./elf_gen 4194304 OvmfPkg/CloudHv/CloudHvElfHeader.fdf.inc

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
 OvmfPkg/CloudHv/CloudHvElfHeader.fdf.inc | 54 ++++++++++++++++++++++++
 OvmfPkg/CloudHv/CloudHvX64.dsc           |  2 +-
 OvmfPkg/CloudHv/CloudHvX64.fdf           | 15 +++++--
 3 files changed, 66 insertions(+), 5 deletions(-)
 create mode 100644 OvmfPkg/CloudHv/CloudHvElfHeader.fdf.inc

diff --git a/OvmfPkg/CloudHv/CloudHvElfHeader.fdf.inc b/OvmfPkg/CloudHv/CloudHvElfHeader.fdf.inc
new file mode 100644
index 0000000000..8377e30bdc
--- /dev/null
+++ b/OvmfPkg/CloudHv/CloudHvElfHeader.fdf.inc
@@ -0,0 +1,54 @@
+## @file
+#  FDF include file that defines a PVH ELF header.
+#
+#  Copyright (c) 2022, Intel Corporation. All rights reserved.
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+DATA = {
+  # ELF file header
+  0x7f, 0x45, 0x4c, 0x46, 0x02, 0x01, 0x01, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x03, 0x00, 0x01, 0x00, 0x00, 0x00,
+  0xd0, 0xff, 0x4f, 0x00, 0x00, 0x00, 0x00, 0x00, # hdr.e_entry
+  0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x38, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+
+  # ELF Program segment headers
+  # - Load segment
+  0x01, 0x00, 0x00, 0x00,
+  0x07, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x10, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x10, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x40, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x40, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x04, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  # - ELFNOTE segment
+  0x04, 0x00, 0x00, 0x00,
+  0x04, 0x00, 0x00, 0x00,
+  0xb0, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0xb0, 0x00, 0x10, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0xb0, 0x00, 0x10, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x14, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x14, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+  0x04, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00,
+
+  # XEN_ELFNOTE_PHYS32_ENTRY
+  0x04, 0x00, 0x00, 0x00,
+  0x04, 0x00, 0x00, 0x00,
+  0x12, 0x00, 0x00, 0x00,
+  0x58, 0x65, 0x6e, 0x00,
+  0xd0, 0xff, 0x4f, 0x00
+}
diff --git a/OvmfPkg/CloudHv/CloudHvX64.dsc b/OvmfPkg/CloudHv/CloudHvX64.dsc
index 3172100310..b4d855d80f 100644
--- a/OvmfPkg/CloudHv/CloudHvX64.dsc
+++ b/OvmfPkg/CloudHv/CloudHvX64.dsc
@@ -631,7 +631,7 @@
 #
 ################################################################################
 [Components]
-  OvmfPkg/ResetVector/ResetVector.inf
+  OvmfPkg/XenResetVector/XenResetVector.inf
 
   #
   # SEC Phase modules
diff --git a/OvmfPkg/CloudHv/CloudHvX64.fdf b/OvmfPkg/CloudHv/CloudHvX64.fdf
index 0974e76ac8..282bcf8634 100644
--- a/OvmfPkg/CloudHv/CloudHvX64.fdf
+++ b/OvmfPkg/CloudHv/CloudHvX64.fdf
@@ -14,8 +14,8 @@
 !include OvmfPkg/OvmfPkgDefines.fdf.inc
 
 #
-# Build the variable store and the firmware code as one unified flash device
-# image.
+# This will allow the flash device image to be recognize as an ELF, with first
+# an ELF headers, then the firmware code.
 #
 [FD.CLOUDHV]
 BaseAddress   = $(FW_BASE_ADDRESS)
@@ -24,7 +24,14 @@ ErasePolarity = 1
 BlockSize     = $(BLOCK_SIZE)
 NumBlocks     = $(FW_BLOCKS)
 
-0x00000000|$(FVMAIN_SIZE)
+#
+# Leaving 4kiB for the PVH ELF header. This is more than enough.
+#
+0x00000000|0x00001000
+
+!include CloudHvElfHeader.fdf.inc
+
+0x00001000|$(FVMAIN_SIZE)
 FV = FVMAIN_COMPACT
 
 $(SECFV_OFFSET)|$(SECFV_SIZE)
@@ -114,7 +121,7 @@ READ_LOCK_STATUS   = TRUE
 #
 INF  OvmfPkg/Sec/SecMain.inf
 
-INF  RuleOverride=RESET_VECTOR OvmfPkg/ResetVector/ResetVector.inf
+INF  RuleOverride=RESET_VECTOR OvmfPkg/XenResetVector/XenResetVector.inf
 
 ################################################################################
 [FV.PEIFV]