From 6bfd26f3810e82ce0c8f78f1ad4e5ee7471c11e7 Mon Sep 17 00:00:00 2001
From: vit9696 <vit9696@users.noreply.github.com>
Date: Wed, 13 May 2020 15:30:03 +0300
Subject: [PATCH] OcCpuLib: Fixed CPU detection crash with QEMU 5.0 and KVM
 accelerator

closes acidanthera/bugtracker#914
---
 Changelog.md                | 1 +
 Library/OcCpuLib/OcCpuLib.c | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Changelog.md b/Changelog.md
index 9eb00d2f..ebb46c31 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -21,6 +21,7 @@ OpenCore Changelog
 - Added partial hotkey support to OpenCanopy (e.g. Ctrl+Enter)
 - Added builtin text renderer compatibility with Shell page mode
 - Fixed `FadtEnableReset` with too small FACP tables
+- Fixed CPU detection crash with QEMU 5.0 and KVM accelerator
 
 #### v0.5.8
 - Fixed invalid CPU object reference in SSDT-PLUG
diff --git a/Library/OcCpuLib/OcCpuLib.c b/Library/OcCpuLib/OcCpuLib.c
index 8489acb5..d98c7de8 100755
--- a/Library/OcCpuLib/OcCpuLib.c
+++ b/Library/OcCpuLib/OcCpuLib.c
@@ -300,9 +300,15 @@ ScanIntelProcessor (
     return;
   }
 
-  if (Cpu->Model >= CPU_MODEL_SANDYBRIDGE) {
+  //
+  // Some virtual machines like QEMU 5.0 with KVM will fail to read this value.
+  // REF: https://github.com/acidanthera/bugtracker/issues/914
+  //
+  if (Cpu->Model >= CPU_MODEL_SANDYBRIDGE && !Cpu->Hypervisor) {
     PkgCstConfigControl.Uint64 = AsmReadMsr64 (MSR_SANDY_BRIDGE_PKG_CST_CONFIG_CONTROL);
     Cpu->CstConfigLock = PkgCstConfigControl.Bits.CFGLock == 1;
+  } else {
+    Cpu->CstConfigLock = FALSE;
   }
 
   //
-- 
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