From ec18fa81d311663e24e9b9ad61b90b38862a1ea8 Mon Sep 17 00:00:00 2001
From: Ceping Sun <cepingx.sun@intel.com>
Date: Thu, 29 Aug 2024 07:34:47 +0800
Subject: OvmfPkg: Use TdInfo instead of fw_cfg to get cpu count in TDVF

Currently TDVF gets cpu count information via fw_cfg, but
this information can also be retrieved by calling of TdCall.TdInfo.

And TdCall is responded by tdx-module which is trust.
So, from the security perspective we shall use TdCall.Tdinfo instead
of fw_cfg.

Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Ceping Sun <cepingx.sun@intel.com>
---
 OvmfPkg/Library/PlatformInitLib/Platform.c          | 15 +++++++++++++++
 OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf |  2 --
 OvmfPkg/OvmfPkgIa32.dsc                             |  1 +
 3 files changed, 16 insertions(+), 2 deletions(-)

(limited to 'OvmfPkg')

diff --git a/OvmfPkg/Library/PlatformInitLib/Platform.c b/OvmfPkg/Library/PlatformInitLib/Platform.c
index c2e0430d22..10fc17355f 100644
--- a/OvmfPkg/Library/PlatformInitLib/Platform.c
+++ b/OvmfPkg/Library/PlatformInitLib/Platform.c
@@ -33,6 +33,7 @@
 #include <Guid/SystemNvDataGuid.h>
 #include <Guid/VariableFormat.h>
 #include <OvmfPlatforms.h>
+#include <Library/TdxLib.h>
 
 #include <Library/PlatformInitLib.h>
 
@@ -563,6 +564,20 @@ PlatformMaxCpuCountInitialization (
   UINT16  BootCpuCount = 0;
   UINT32  MaxCpuCount;
 
+  if (TdIsEnabled ()) {
+    BootCpuCount = (UINT16)TdVCpuNum ();
+    MaxCpuCount  = TdMaxVCpuNum ();
+
+    if (BootCpuCount > MaxCpuCount) {
+      DEBUG ((DEBUG_ERROR, "%a: Failed with BootCpuCount (%d) more than MaxCpuCount(%u) \n", __func__, BootCpuCount, MaxCpuCount));
+      ASSERT (FALSE);
+    }
+
+    PlatformInfoHob->PcdCpuMaxLogicalProcessorNumber  = MaxCpuCount;
+    PlatformInfoHob->PcdCpuBootLogicalProcessorNumber = BootCpuCount;
+    return;
+  }
+
   //
   // Try to fetch the boot CPU count.
   //
diff --git a/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf b/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf
index e9c07467bb..3e63ef4423 100644
--- a/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf
+++ b/OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf
@@ -53,8 +53,6 @@
   PcdLib
   PciLib
   PeiHardwareInfoLib
-
-[LibraryClasses.X64]
   TdxLib
 
 [Guids]
diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index 5e2086eb33..34f7b9958b 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -251,6 +251,7 @@
   AmdSvsmLib|UefiCpuPkg/Library/AmdSvsmLibNull/AmdSvsmLibNull.inf
   BaseCryptLib|CryptoPkg/Library/BaseCryptLib/BaseCryptLib.inf
   CcExitLib|UefiCpuPkg/Library/CcExitLibNull/CcExitLibNull.inf
+  TdxLib|MdePkg/Library/TdxLib/TdxLib.inf
   TdxMailboxLib|OvmfPkg/Library/TdxMailboxLib/TdxMailboxLibNull.inf
 
 [LibraryClasses.common.SEC]
-- 
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