[PATCH] MdeModulePkg: Disambiguate the meaning of PcdDxeIplSwitchToLongMode

[PATCH] MdeModulePkg: Disambiguate the meaning of PcdDxeIplSwitchToLongMode

[Zhiguang Liu]

Literally, the meaning of PcdDxeIplSwitchToLongMode is clear, indicating
whether need switch to long mode when loading DxeCore.
However, the comments in dec are confusing for the case where PEI core and
DXE core are both in 64-bit. This patch makes it clear.
PcdDxeIplSwitchToLongMode is true only when PEI core is 32-bit, and switch
to long mode to load 64-bit DXE core. In other cases, this PCD is false.
This also aligns with current usage in OvmfPkg.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Ray Ni <ray.ni@intel.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
---
 MdeModulePkg/MdeModulePkg.dec | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index be5e829ca9..5e4535e353 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -922,10 +922,8 @@
 
 [PcdsFeatureFlag.IA32, PcdsFeatureFlag.X64]
   ## Indicates if DxeIpl should switch to long mode to enter DXE phase.
-  #  It is assumed that 64-bit DxeCore is built in firmware if it is true; otherwise 32-bit DxeCore
-  #  is built in firmware.<BR><BR>
   #   TRUE  - DxeIpl will load a 64-bit DxeCore and switch to long mode to hand over to DxeCore.<BR>
-  #   FALSE - DxeIpl will load a 32-bit DxeCore and perform stack switch to hand over to DxeCore.<BR>
+  #   FALSE - DxeIpl will load a 32-bit or 64-bit DxeCore and perform stack switch to hand over to DxeCore.<BR>
   # @Prompt DxeIpl switch to long mode.
   gEfiMdeModulePkgTokenSpaceGuid.PcdDxeIplSwitchToLongMode|TRUE|BOOLEAN|0x0001003b
 
-- 
2.31.1.windows.1

Re: [edk2-devel] [PATCH] MdeModulePkg: Disambiguate the meaning of PcdDxeIplSwitchToLongMode

[Ni, Ray]

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

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Re: [edk2-devel] [PATCH] MdeModulePkg: Disambiguate the meaning of PcdDxeIplSwitchToLongMode

[Zhiguang Liu]

Hi Liming and Jian,

What do you think about this patch?

Thanks
Zhiguang

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> Zhiguang Liu
> Sent: Monday, January 9, 2023 11:34 AM
> To: devel@edk2.groups.io
> Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Wang, Jian J
> <jian.j.wang@intel.com>; Gao, Liming <gaoliming@byosoft.com.cn>; Ni, Ray
> <ray.ni@intel.com>
> Subject: [edk2-devel] [PATCH] MdeModulePkg: Disambiguate the meaning
> of PcdDxeIplSwitchToLongMode
> 
> Literally, the meaning of PcdDxeIplSwitchToLongMode is clear, indicating
> whether need switch to long mode when loading DxeCore.
> However, the comments in dec are confusing for the case where PEI core
> and DXE core are both in 64-bit. This patch makes it clear.
> PcdDxeIplSwitchToLongMode is true only when PEI core is 32-bit, and switch
> to long mode to load 64-bit DXE core. In other cases, this PCD is false.
> This also aligns with current usage in OvmfPkg.
> 
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> Cc: Ray Ni <ray.ni@intel.com>
> Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
> ---
>  MdeModulePkg/MdeModulePkg.dec | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/MdeModulePkg/MdeModulePkg.dec
> b/MdeModulePkg/MdeModulePkg.dec index be5e829ca9..5e4535e353
> 100644
> --- a/MdeModulePkg/MdeModulePkg.dec
> +++ b/MdeModulePkg/MdeModulePkg.dec
> @@ -922,10 +922,8 @@
> 
>  [PcdsFeatureFlag.IA32, PcdsFeatureFlag.X64]
>    ## Indicates if DxeIpl should switch to long mode to enter DXE phase.
> -  #  It is assumed that 64-bit DxeCore is built in firmware if it is true;
> otherwise 32-bit DxeCore
> -  #  is built in firmware.<BR><BR>
>    #   TRUE  - DxeIpl will load a 64-bit DxeCore and switch to long mode to hand
> over to DxeCore.<BR>
> -  #   FALSE - DxeIpl will load a 32-bit DxeCore and perform stack switch to
> hand over to DxeCore.<BR>
> +  #   FALSE - DxeIpl will load a 32-bit or 64-bit DxeCore and perform stack
> switch to hand over to DxeCore.<BR>
>    # @Prompt DxeIpl switch to long mode.
> 
> gEfiMdeModulePkgTokenSpaceGuid.PcdDxeIplSwitchToLongMode|TRUE|B
> OOLEAN|0x0001003b
> 
> --
> 2.31.1.windows.1
> 
> 
> 
> 
> 

Re: [edk2-devel] [PATCH] MdeModulePkg: Disambiguate the meaning of PcdDxeIplSwitchToLongMode

[Zhiguang Liu]

Thanks Liming for reviewing this patch.
Could you help push this change?

Thanks
Zhiguang

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> gaoliming via groups.io
> Sent: Thursday, February 2, 2023 11:10 AM
> To: Liu, Zhiguang <zhiguang.liu@intel.com>; devel@edk2.groups.io; Wang,
> Jian J <jian.j.wang@intel.com>
> Cc: Ni, Ray <ray.ni@intel.com>
> Subject: 回复: [edk2-devel] [PATCH] MdeModulePkg: Disambiguate the
> meaning of PcdDxeIplSwitchToLongMode
> 
> It is good to me. Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
> 
> > -----邮件原件-----
> > 发件人: Liu, Zhiguang <zhiguang.liu@intel.com>
> > 发送时间: 2023年2月1日 13:28
> > 收件人: devel@edk2.groups.io; Liu, Zhiguang <zhiguang.liu@intel.com>;
> > Gao, Liming <gaoliming@byosoft.com.cn>; Wang, Jian J
> > <jian.j.wang@intel.com>
> > 抄送: Ni, Ray <ray.ni@intel.com>
> > 主题: RE: [edk2-devel] [PATCH] MdeModulePkg: Disambiguate the
> meaning of
> > PcdDxeIplSwitchToLongMode
> >
> > Hi Liming and Jian,
> >
> > What do you think about this patch?
> >
> > Thanks
> > Zhiguang
> >
> > > -----Original Message-----
> > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> > > Zhiguang Liu
> > > Sent: Monday, January 9, 2023 11:34 AM
> > > To: devel@edk2.groups.io
> > > Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Wang, Jian J
> > > <jian.j.wang@intel.com>; Gao, Liming <gaoliming@byosoft.com.cn>; Ni,
> > > Ray <ray.ni@intel.com>
> > > Subject: [edk2-devel] [PATCH] MdeModulePkg: Disambiguate the
> meaning
> > > of PcdDxeIplSwitchToLongMode
> > >
> > > Literally, the meaning of PcdDxeIplSwitchToLongMode is clear,
> > > indicating whether need switch to long mode when loading DxeCore.
> > > However, the comments in dec are confusing for the case where PEI
> > > core and DXE core are both in 64-bit. This patch makes it clear.
> > > PcdDxeIplSwitchToLongMode is true only when PEI core is 32-bit, and
> switch
> > > to long mode to load 64-bit DXE core. In other cases, this PCD is false.
> > > This also aligns with current usage in OvmfPkg.
> > >
> > > Cc: Jian J Wang <jian.j.wang@intel.com>
> > > Cc: Liming Gao <gaoliming@byosoft.com.cn>
> > > Cc: Ray Ni <ray.ni@intel.com>
> > > Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
> > > ---
> > >  MdeModulePkg/MdeModulePkg.dec | 4 +---
> > >  1 file changed, 1 insertion(+), 3 deletions(-)
> > >
> > > diff --git a/MdeModulePkg/MdeModulePkg.dec
> > > b/MdeModulePkg/MdeModulePkg.dec index be5e829ca9..5e4535e353
> > > 100644
> > > --- a/MdeModulePkg/MdeModulePkg.dec
> > > +++ b/MdeModulePkg/MdeModulePkg.dec
> > > @@ -922,10 +922,8 @@
> > >
> > >  [PcdsFeatureFlag.IA32, PcdsFeatureFlag.X64]
> > >    ## Indicates if DxeIpl should switch to long mode to enter DXE phase.
> > > -  #  It is assumed that 64-bit DxeCore is built in firmware if it
> > > is
> true;
> > > otherwise 32-bit DxeCore
> > > -  #  is built in firmware.<BR><BR>
> > >    #   TRUE  - DxeIpl will load a 64-bit DxeCore and switch to long
> > mode to hand
> > > over to DxeCore.<BR>
> > > -  #   FALSE - DxeIpl will load a 32-bit DxeCore and perform stack
> switch
> > to
> > > hand over to DxeCore.<BR>
> > > +  #   FALSE - DxeIpl will load a 32-bit or 64-bit DxeCore and perform
> > stack
> > > switch to hand over to DxeCore.<BR>
> > >    # @Prompt DxeIpl switch to long mode.
> > >
> > >
> gEfiMdeModulePkgTokenSpaceGuid.PcdDxeIplSwitchToLongMode|TRUE|B
> > > OOLEAN|0x0001003b
> > >
> > > --
> > > 2.31.1.windows.1
> > >
> > >
> > >
> > >
> > >
> 
> 
> 
> 
> 
> 
>