Re: [PATCH] UefiCpuPkg/MpInitLib: Disable interrupt at ExitBootServices AP Mwait

["Ni, Ruiyu" <ruiyu.ni@Intel.com>]

On 3/19/2018 1:31 PM, Hao Wu wrote:
> Within function ApWakeupFunction():
> 
> When source level debugger is enabled, AP interrupts will be enabled by
> EnableDebugAgent(). Then the AP function will be execeuted by:
> 
> Procedure (Parameter);
> 
> After the AP function returns, AP interrupts will be disabled when the
> APs are placed in loop mode (both HltLoop and MwaiLoop).
> 
> However, at ExitBootServices, ApWakeupFunction() is called with
> 'Procedure' equals to RelocateApLoop().
> 
> (ExitBootServices callback registered within InitMpGlobalData())
> 
> RelocateApLoop() never retuns, so it has to disable the AP interrupts by
> itself. However, we find that interrupts are only disabled for the
> HltLoop case, but not for the MwaitLoop case (within file MpFuncs.nasm).
> 
> This commit adds the missing disabling of AP interrupts for MwaitLoop.
> 
> Also, for X64, this commit will disable the interrupts before switching to
> 32-bit mode.
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Jeff Fan <vanjeff_919@hotmail.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Hao Wu <hao.a.wu@intel.com>
> ---
>   UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm | 3 ++-
>   UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm  | 4 +++-
>   2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
> index bd79be0f5e..59e88d3f8f 100644
> --- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
> +++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
> @@ -1,5 +1,5 @@
>   ;------------------------------------------------------------------------------ ;
> -; Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
> +; Copyright (c) 2015 - 2018, Intel Corporation. All rights reserved.<BR>
>   ; This program and the accompanying materials
>   ; are licensed and made available under the terms and conditions of the BSD License
>   ; which accompanies this distribution.  The full text of the license may be found at
> @@ -239,6 +239,7 @@ AsmRelocateApLoopStart:
>       cmp        cl,  1              ; Check mwait-monitor support
>       jnz        HltLoop
>   MwaitLoop:
> +    cli
>       mov        eax, esp
>       xor        ecx, ecx
>       xor        edx, edx
> diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
> index 7595988884..76f8c078ab 100644
> --- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
> +++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
> @@ -1,5 +1,5 @@
>   ;------------------------------------------------------------------------------ ;
> -; Copyright (c) 2015 - 2017, Intel Corporation. All rights reserved.<BR>
> +; Copyright (c) 2015 - 2018, Intel Corporation. All rights reserved.<BR>
>   ; This program and the accompanying materials
>   ; are licensed and made available under the terms and conditions of the BSD License
>   ; which accompanies this distribution.  The full text of the license may be found at
> @@ -253,6 +253,7 @@ RendezvousFunnelProcEnd:
>   global ASM_PFX(AsmRelocateApLoop)
>   ASM_PFX(AsmRelocateApLoop):
>   AsmRelocateApLoopStart:
> +    cli                          ; Disable interrupt before switching to 32-bit mode
>       mov        rax, [rsp + 40]   ; CountTofinish
>       lock dec   dword [rax]       ; (*CountTofinish)--
>       mov        rsp, r9
> @@ -288,6 +289,7 @@ PmEntry:
>       jnz        HltLoop
>       mov        ebx, edx           ; Save C-State to ebx
>   MwaitLoop:
> +    cli
>       mov        eax, esp           ; Set Monitor Address
>       xor        ecx, ecx           ; ecx = 0
>       xor        edx, edx           ; edx = 0
> 
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

-- 
Thanks,
Ray