Re: [PATCH V8 35/47] MdeModulePkg: Skip setting IA32_ERER.NXE if it has already been set

["Wang, Jian J" <jian.j.wang@intel.com>]

Reviewed-by: Jian J Wang <jian.j.wang@intel.com>

Regards,
Jian

> -----Original Message-----
> From: Xu, Min M <min.m.xu@intel.com>
> Sent: Saturday, March 12, 2022 9:54 AM
> To: devel@edk2.groups.io
> Cc: Xu, Min M <min.m.xu@intel.com>; Wang, Jian J <jian.j.wang@intel.com>;
> Wu, Hao A <hao.a.wu@intel.com>; Brijesh Singh <brijesh.singh@amd.com>;
> Aktas, Erdem <erdemaktas@google.com>; James Bottomley
> <jejb@linux.ibm.com>; Yao, Jiewen <jiewen.yao@intel.com>; Tom Lendacky
> <thomas.lendacky@amd.com>; Gerd Hoffmann <kraxel@redhat.com>
> Subject: [PATCH V8 35/47] MdeModulePkg: Skip setting IA32_ERER.NXE if it has
> already been set
> 
> RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
> 
> If IA32_ERER.NXE has already been set, skip setting it again.
> 
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: Erdem Aktas <erdemaktas@google.com>
> Cc: James Bottomley <jejb@linux.ibm.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Min Xu <min.m.xu@intel.com>
> ---
>  MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> index 0700f310b203..bb426d0d0a6f 100644
> --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> @@ -179,9 +179,11 @@ EnableExecuteDisableBit (
>  {
>    UINT64  MsrRegisters;
> 
> -  MsrRegisters  = AsmReadMsr64 (0xC0000080);
> -  MsrRegisters |= BIT11;
> -  AsmWriteMsr64 (0xC0000080, MsrRegisters);
> +  MsrRegisters = AsmReadMsr64 (0xC0000080);
> +  if ((MsrRegisters & BIT11) == 0) {
> +    MsrRegisters |= BIT11;
> +    AsmWriteMsr64 (0xC0000080, MsrRegisters);
> +  }
>  }
> 
>  /**
> --
> 2.29.2.windows.2