Re: [edk2-devel] [PATCH] UefiCpuPkg: Calculate DisplayFamily correctly

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

@Liu, Zhiguang, can you check if Mike's suggestion "+" instead of "|" is more matching to SDM?

If yes, we can create another code patch.

> -----Original Message-----
> From: Mike Maslenkin <mike.maslenkin@gmail.com>
> Sent: Monday, March 6, 2023 9:37 PM
> To: devel@edk2.groups.io; Ni, Ray <ray.ni@intel.com>
> Subject: Re: [edk2-devel] [PATCH] UefiCpuPkg: Calculate DisplayFamily
> correctly
> 
> There is no problem with current implementation.
> My proposal was to re-write code in this way:
> 
>   DisplayModel = Eax.Bits.Model;
>   if ((Eax.Bits.FamilyId == 0x06) || (Eax.Bits.FamilyId == 0x0f)) {
>     DisplayModel += (Eax.Bits.ExtendedModelId << 4);
>   }
> 
> This is exactly matches spec without knowledge about Model_ID width
> and makes code consistent.
> 
> There is no 'OR" operation in rules defined by SDM:
> "
> IF (Family_ID = 06H or Family_ID = 0FH)
>   THEN DisplayModel = (Extended_Model_ID « 4) + Model_ID;
>   (* Right justify and zero-extend 4-bit field; display Model_ID as
> HEX field.*) ELSE DisplayModel = Model_ID;
> FI;
> "
> 
> 
> "
> 
> On Mon, Mar 6, 2023 at 2:52 PM Ni, Ray <ray.ni@intel.com> wrote:
> >
> > ExtendedModelId field should use shift. So I believe nothing wrong there.
> >
> > > -----Original Message-----
> > > From: Mike Maslenkin <mike.maslenkin@gmail.com>
> > > Sent: Monday, March 6, 2023 7:14 PM
> > > To: devel@edk2.groups.io; Zeng, Star <star.zeng@intel.com>
> > > Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Dong, Eric
> > > <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Kumar, Rahul R
> > > <rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com>
> > > Subject: Re: [edk2-devel] [PATCH] UefiCpuPkg: Calculate DisplayFamily
> > > correctly
> > >
> > > Handling of ExtendedModelId field has the same problem.
> > > This patch could be improved to fix that too.
> > >
> > > On Mon, Mar 6, 2023 at 1:37 PM Zeng, Star <star.zeng@intel.com> wrote:
> > > >
> > > > BTW, look like wrong Bugzilla ID is used in commit message, please
> correct
> > > it when merging the patch.
> > > >
> > > > -----Original Message-----
> > > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> Zeng,
> > > Star
> > > > Sent: Monday, March 6, 2023 6:35 PM
> > > > To: devel@edk2.groups.io; Liu, Zhiguang <zhiguang.liu@intel.com>
> > > > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> Kumar,
> > > Rahul R <rahul.r.kumar@intel.com>; Gerd Hoffmann
> <kraxel@redhat.com>;
> > > Zeng, Star <star.zeng@intel.com>
> > > > Subject: Re: [edk2-devel] [PATCH] UefiCpuPkg: Calculate DisplayFamily
> > > correctly
> > > >
> > > > Reviewed-by: Star Zeng <star.zeng@intel.com>
> > > >
> > > > -----Original Message-----
> > > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> > > Zhiguang Liu
> > > > Sent: Thursday, March 2, 2023 9:27 AM
> > > > To: devel@edk2.groups.io
> > > > Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Dong, Eric
> > > <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; Kumar, Rahul R
> > > <rahul.r.kumar@intel.com>; Gerd Hoffmann <kraxel@redhat.com>
> > > > Subject: [edk2-devel] [PATCH] UefiCpuPkg: Calculate DisplayFamily
> > > correctly
> > > >
> > > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4238
> > > >
> > > > Per SDM, DisplayFamily = Extended_Family_ID + Family_ID.
> > > > Correct the related code.
> > > >
> > > > Cc: Eric Dong <eric.dong@intel.com>
> > > > Cc: Ray Ni <ray.ni@intel.com>
> > > > Cc: Rahul Kumar <rahul1.kumar@intel.com>
> > > > Cc: Gerd Hoffmann <kraxel@redhat.com>
> > > > Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
> > > > ---
> > > >  UefiCpuPkg/Application/Cpuid/Cpuid.c                          | 4 ++--
> > > >  .../Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c    | 4 ++--
> > > >  2 files changed, 4 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/UefiCpuPkg/Application/Cpuid/Cpuid.c
> > > b/UefiCpuPkg/Application/Cpuid/Cpuid.c
> > > > index 372c6ef87d..51c463fb10 100644
> > > > --- a/UefiCpuPkg/Application/Cpuid/Cpuid.c
> > > > +++ b/UefiCpuPkg/Application/Cpuid/Cpuid.c
> > > > @@ -1,7 +1,7 @@
> > > >  /** @file
> > > >    UEFI Application to display CPUID leaf information.
> > > >
> > > > -  Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.<BR>
> > > > +  Copyright (c) 2016 - 2023, Intel Corporation. All rights reserved.<BR>
> > > >    SPDX-License-Identifier: BSD-2-Clause-Patent
> > > >
> > > >  **/
> > > > @@ -217,7 +217,7 @@ CpuidVersionInfo (
> > > >
> > > >    DisplayFamily = Eax.Bits.FamilyId;
> > > >    if (Eax.Bits.FamilyId == 0x0F) {
> > > > -    DisplayFamily |= (Eax.Bits.ExtendedFamilyId << 4);
> > > > +    DisplayFamily += Eax.Bits.ExtendedFamilyId;
> > > >    }
> > > >
> > > >    DisplayModel = Eax.Bits.Model;
> > > > diff --git
> > > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > > index a8e4f920fc..25b8958252 100644
> > > > ---
> a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > > +++
> b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > > @@ -1,7 +1,7 @@
> > > >  /** @file
> > > >    CPU Features Initialize functions.
> > > >
> > > > -  Copyright (c) 2017 - 2021, Intel Corporation. All rights reserved.<BR>
> > > > +  Copyright (c) 2017 - 2023, Intel Corporation. All rights reserved.<BR>
> > > >    SPDX-License-Identifier: BSD-2-Clause-Patent
> > > >
> > > >  **/
> > > > @@ -67,7 +67,7 @@ FillProcessorInfo (
> > > >
> > > >    DisplayedFamily = Eax.Bits.FamilyId;
> > > >    if (Eax.Bits.FamilyId == 0x0F) {
> > > > -    DisplayedFamily |= (Eax.Bits.ExtendedFamilyId << 4);
> > > > +    DisplayedFamily += Eax.Bits.ExtendedFamilyId;
> > > >    }
> > > >
> > > >    DisplayedModel = Eax.Bits.Model;
> > > > --
> > > > 2.31.1.windows.1
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