Re: [edk2-devel] [PATCH v6 4/6] UefiCpuPkg: Only change CR4.CET bit for enable and disable CET.

["Ni, Ray" <ray.ni@intel.com>]

Reviewed-by: Ray Ni <ray.ni@intel.com>

Thanks,
Ray
> -----Original Message-----
> From: Sheng, W <w.sheng@intel.com>
> Sent: Tuesday, November 21, 2023 3:03 PM
> To: devel@edk2.groups.io
> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Laszlo
> Ersek <lersek@redhat.com>; Wu, Jiaxin <jiaxin.wu@intel.com>; Tan, Dun
> <dun.tan@intel.com>
> Subject: [PATCH v6 4/6] UefiCpuPkg: Only change CR4.CET bit for enable and
> disable CET.
> 
> 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 | 10 +++++++---
>  UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm  | 10 +++++++---
>  2 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
> b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
> index 6368982433..1da9afab97 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmiEntry.nasm
> @@ -237,7 +237,9 @@ CetInterruptDone:
>      bts     ecx, 16                     ; set WP
> 
>      mov     cr0, ecx
> 
> 
> 
> -    mov     eax, 0x668 | CR4_CET
> 
> +    ; set CR4.CET bit for enable CET
> 
> +    mov     eax, cr4
> 
> +    bts     eax, CR4_CET_BIT
> 
>      mov     cr4, eax
> 
> 
> 
>      setssbsy
> 
> @@ -264,8 +266,10 @@ CetDone:
>      cmp     al, 0
> 
>      jz      CetDone2
> 
> 
> 
> -    mov     eax, 0x668
> 
> -    mov     cr4, eax       ; disable CET
> 
> +    ; clear CR4.CET bit for disable CET
> 
> +    mov     eax, cr4
> 
> +    btr     eax, CR4_CET_BIT
> 
> +    mov     cr4, eax
> 
> 
> 
>      mov     ecx, MSR_IA32_PL0_SSP
> 
>      pop     eax
> 
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
> b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
> index 9a225bc3be..abf9f1a90a 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmiEntry.nasm
> @@ -263,7 +263,9 @@ CetInterruptDone:
>      bts     ecx, 16                     ; set WP
> 
>      mov     cr0, rcx
> 
> 
> 
> -    mov     eax, 0x668 | CR4_CET
> 
> +    ; set CR4.CET bit for enable CET
> 
> +    mov     rax, cr4
> 
> +    bts     rax, CR4_CET_BIT
> 
>      mov     cr4, rax
> 
> 
> 
>      setssbsy
> 
> @@ -308,8 +310,10 @@ mCetSupportedAbsAddr:
>      cmp     al, 0
> 
>      jz      CetDone2
> 
> 
> 
> -    mov     eax, 0x668
> 
> -    mov     cr4, rax       ; disable CET
> 
> +    ; clear CR4.CET bit for disable CET
> 
> +    mov     rax, cr4
> 
> +    btr     rax, CR4_CET_BIT
> 
> +    mov     cr4, rax
> 
> 
> 
>      mov     ecx, MSR_IA32_INTERRUPT_SSP_TABLE_ADDR
> 
>      pop     rax
> 
> --
> 2.26.2.windows.1



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