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From: "Sheng Wei" <w.sheng@intel.com>
To: devel@edk2.groups.io
Cc: Eric Dong <eric.dong@intel.com>, Ray Ni <ray.ni@intel.com>,
	Laszlo Ersek <lersek@redhat.com>, Wu Jiaxin <jiaxin.wu@intel.com>,
	Tan Dun <dun.tan@intel.com>
Subject: [edk2-devel] [PATCH v6 5/6] UefiCpuPkg: Backup and Restore MSR IA32_U_CET in SMI handler.
Date: Tue, 21 Nov 2023 15:02:45 +0800	[thread overview]
Message-ID: <20231121070246.505-6-w.sheng@intel.com> (raw)
In-Reply-To: <20231121070246.505-1-w.sheng@intel.com>

OS may enable CET-IBT feature by set MSR IA32_U_CET.bit2.
If IA32_U_CET.bit2 is set, CPU is in WAIT_FOR_ENDBRANCH state and
 the next assemble code is not ENDBR, it will trigger #CP exception
 when set CR4.CET bit.
SMI handler needs to backup MSR IA32_U_CET and clear MSR IA32_U_CET
 before set CR4.CET bit,
And SMI handler needs to restore MSR IA32_U_CET when exit SMI handler.

Signed-off-by: Sheng Wei <w.sheng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Wu Jiaxin <jiaxin.wu@intel.com>
Cc: Tan Dun <dun.tan@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
---
 UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm | 15 +++++++++++++++
 UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm  | 15 +++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
index 1da9afab97..9e1155dee6 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
@@ -202,11 +202,21 @@ ASM_PFX(mPatchCetSupported):
     push    edx
     push    eax
 
+    mov     ecx, MSR_IA32_U_CET
+    rdmsr
+    push    edx
+    push    eax
+
     mov     ecx, MSR_IA32_PL0_SSP
     rdmsr
     push    edx
     push    eax
 
+    mov     ecx, MSR_IA32_U_CET
+    xor     eax, eax
+    xor     edx, edx
+    wrmsr
+
     mov     ecx, MSR_IA32_S_CET
     mov     eax, MSR_IA32_CET_SH_STK_EN
     xor     edx, edx
@@ -276,6 +286,11 @@ CetDone:
     pop     edx
     wrmsr
 
+    mov     ecx, MSR_IA32_U_CET
+    pop     eax
+    pop     edx
+    wrmsr
+
     mov     ecx, MSR_IA32_S_CET
     pop     eax
     pop     edx
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
index abf9f1a90a..881d3177f7 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
@@ -217,6 +217,11 @@ ASM_PFX(mPatchCetSupported):
     push    rdx
     push    rax
 
+    mov     ecx, MSR_IA32_U_CET
+    rdmsr
+    push    rdx
+    push    rax
+
     mov     ecx, MSR_IA32_PL0_SSP
     rdmsr
     push    rdx
@@ -227,6 +232,11 @@ ASM_PFX(mPatchCetSupported):
     push    rdx
     push    rax
 
+    mov     ecx, MSR_IA32_U_CET
+    xor     eax, eax
+    xor     edx, edx
+    wrmsr
+
     mov     ecx, MSR_IA32_S_CET
     mov     eax, MSR_IA32_CET_SH_STK_EN
     xor     edx, edx
@@ -325,6 +335,11 @@ mCetSupportedAbsAddr:
     pop     rdx
     wrmsr
 
+    mov     ecx, MSR_IA32_U_CET
+    pop     rax
+    pop     rdx
+    wrmsr
+
     mov     ecx, MSR_IA32_S_CET
     pop     rax
     pop     rdx
-- 
2.26.2.windows.1



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  parent reply	other threads:[~2023-11-21  7:03 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-21  7:02 [edk2-devel] [PATCH v6 0/6] MdePkg: Add macro definitions for CET feature for NASM files Sheng Wei
2023-11-21  7:02 ` [edk2-devel] [PATCH v6 1/6] " Sheng Wei
2023-11-21  7:53   ` Ni, Ray
2023-11-22 16:51     ` Laszlo Ersek
2023-11-24  7:54       ` Ni, Ray
2023-11-21  7:02 ` [edk2-devel] [PATCH v6 2/6] UefiCpuPkg: Use macro CR4_CET_BIT to replace hard code value in Cet.nasm Sheng Wei
2023-11-21  7:53   ` Ni, Ray
2023-11-21  7:02 ` [edk2-devel] [PATCH v6 3/6] UefiCpuPkg: Use CET macro definitions in Cet.inc for SmiEntry.nasm files Sheng Wei
2023-11-21  7:53   ` Ni, Ray
2023-11-21  7:02 ` [edk2-devel] [PATCH v6 4/6] UefiCpuPkg: Only change CR4.CET bit for enable and disable CET Sheng Wei
2023-11-21  7:53   ` Ni, Ray
2023-11-21  7:02 ` Sheng Wei [this message]
2023-11-21  7:53   ` [edk2-devel] [PATCH v6 5/6] UefiCpuPkg: Backup and Restore MSR IA32_U_CET in SMI handler Ni, Ray
2023-11-21  7:02 ` [edk2-devel] [PATCH v6 6/6] MdePkg: Use macro CR4_CET_BIT to replace hard code value Sheng Wei
2023-11-21  7:54   ` Ni, Ray

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