Re: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix BcdRevision is not match with SMBIOS version

["Lien, HoraceX" <horacex.lien@intel.com>]

Hi Mike,

The SMBIOS Spec mentions: SMBIOS Major/Minor versions can be > 9. (it have an example on description: "the value is 0Ah for revision 10.22 and 02h for revision2.1").
Therefore, we cannot filter range 0-9 for property of the global variables(mPrivateData.Smbios.MajorVersion/MinorVersion), it can only filter range 0-9 for BcdRevision.
I don't think we need a conversion function to handle it, because of BcdRevision only ONE BYTE can be store Major/Minor version information, Major/Minor takes 4-bit only individually. If the Spec consider that 4-bit BCD format, it maximum can only represent 0-9(decimal) for one of version numbers. 

For BcdRevision field, the Spec mentions: 
"While the SMBIOS Major and Minor Versions (offsets 06h and 07h) currently duplicate the information that is present in the SMBIOS BCD Revision (offset 1Eh), they provide a path for future growth in this specification. The BCD Revision, for example, provides only a single digit for each of the major and minor version numbers. "
"If the value is 00h, only the Major and Minor Versions in offsets 6 and 7 of the Entry Point Structure provide the version information. "
I think that it is reasonable if fill in 0 when one of version numbers > 9.

For current SMBIOS Spec, there is no explicit mention how to do for BcdRevision if version > 9, I just provide an idea from my interpretation of Spec. In the past, it just masking 0x0F/0xF0, I filter 0-9 can more safely use them. Once SMBIOS version > 9, I think that Spec must be give a reasonable explanation for BcdRevision.

Thanks,
Horace Lien

-----Original Message-----
From: Kinney, Michael D <michael.d.kinney@intel.com> 
Sent: Friday, September 15, 2023 1:48 AM
To: Lien, HoraceX <horacex.lien@intel.com>; devel@edk2.groups.io; Gao, Liming <gaoliming@byosoft.com.cn>
Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Bi, Dandan <dandan.bi@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, Zhichao <zhichao.gao@intel.com>; Kinney, Michael D <michael.d.kinney@intel.com>
Subject: RE: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix BcdRevision is not match with SMBIOS version

Forcing to 0 does not sound right.

You did not answer my question about the property of the global variables.

Without knowing the format of the information in the global variables you cannot safely use them.  If they are in BCD then no need to check for out of range.  If they are hex values, then you have to use conversion functions.

Mike

> -----Original Message-----
> From: Lien, HoraceX <horacex.lien@intel.com>
> Sent: Thursday, September 14, 2023 2:33 AM
> To: Kinney, Michael D <michael.d.kinney@intel.com>; 
> devel@edk2.groups.io; Gao, Liming <gaoliming@byosoft.com.cn>
> Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Bi, Dandan 
> <dandan.bi@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, Zhichao 
> <zhichao.gao@intel.com>
> Subject: RE: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix 
> BcdRevision is not match with SMBIOS version
> 
> Hi Mike,
> 
> https://github.com/tianocore/edk2/pull/4771
> I have changed code following rule: It is only accept range 0-9 for 
> Major and Minor version to fill in SmbiosBcdRevision, if one of Major 
> or Minor is greater than 9 then fill in 00h.
> 
> Please help to review this, thanks :)
> 
> Thanks,
> Horace Lien
> 
> -----Original Message-----
> From: Lien, HoraceX
> Sent: Friday, September 8, 2023 5:35 PM
> To: Kinney, Michael D <michael.d.kinney@intel.com>; 
> devel@edk2.groups.io; Gao, Liming <gaoliming@byosoft.com.cn>
> Cc: Liu, Zhiguang <Zhiguang.Liu@intel.com>; Bi, Dandan 
> <dandan.bi@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, Zhichao 
> <zhichao.gao@intel.com>
> Subject: RE: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix 
> BcdRevision is not match with SMBIOS version
> 
> Hi Mike,
> 
> No, we didn't guarantee this before. Add comments to descript BCD 
> field is good point.
> I have reviewed SMBIOS spec for SmbiosBcdRevision field, it mentions 
> "If the value is 00h, only the Major and Minor Versions in offsets 6 
> and 7 of the Entry Point Structure provide the version information. ". 
> So, I have new idea to implement this, I will filter range 0-9 for 
> Major/Minor version to fill in SmbiosBcdRevision, if one of Major or 
> Minor is greater than 9 then fill in 00h.
> Do you think it is ok?
> 
> Thanks for your reply.
> 
> Thanks,
> Horace Lien
> 
> -----Original Message-----
> From: Kinney, Michael D <michael.d.kinney@intel.com>
> Sent: Friday, September 8, 2023 6:05 AM
> To: Lien, HoraceX <horacex.lien@intel.com>; devel@edk2.groups.io; Gao, 
> Liming <gaoliming@byosoft.com.cn>
> Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Bi, Dandan 
> <dandan.bi@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, Zhichao 
> <zhichao.gao@intel.com>; Kinney, Michael D 
> <michael.d.kinney@intel.com>
> Subject: RE: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix 
> BcdRevision is not match with SMBIOS version
> 
> I was asking about the property of the global variables being used in 
> this patch.  Are they already guaranteed to be in BSD format and in 
> range 0..9.  If so, then no additional code changes would be required.
> However, it would be good to add comments about the properties of 
> those global variables and why they can be used to directly assign to 
> fields that are required to be in BSD format.
> 
> Mike
> 
> > -----Original Message-----
> > From: Lien, HoraceX <horacex.lien@intel.com>
> > Sent: Thursday, September 7, 2023 2:41 AM
> > To: devel@edk2.groups.io; Kinney, Michael D 
> > <michael.d.kinney@intel.com>; Gao, Liming <gaoliming@byosoft.com.cn>
> > Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Bi, Dandan 
> > <dandan.bi@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, 
> > Zhichao <zhichao.gao@intel.com>; Lien, HoraceX 
> > <horacex.lien@intel.com>
> > Subject: RE: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix 
> > BcdRevision is not match with SMBIOS version
> >
> > Hi Mike,
> >
> > Could you please reply for me?
> > If you want to filter range 0-9, then I will send PR again.
> >
> > Thanks,
> > Horace Lien
> >
> > -----Original Message-----
> > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Lien, 
> > HoraceX
> > Sent: Friday, September 1, 2023 3:06 PM
> > To: Kinney, Michael D <michael.d.kinney@intel.com>; 
> > devel@edk2.groups.io
> > Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Bi, Dandan 
> > <dandan.bi@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, 
> > Zhichao <zhichao.gao@intel.com>
> > Subject: Re: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix 
> > BcdRevision is not match with SMBIOS version
> >
> > Hi Mike,
> >
> > I have change code to
> > EntryPointStructureData.SmbiosBcdRevision = 
> > ((mPrivateData.Smbios.MajorVersion & 0x0f) << 4) | 
> > (mPrivateData.Smbios.MinorVersion & 0x0f); Add &0x0F to mask upper 
> > nibble bit, do we still need to guarantee that range is between 0-9?
> > Because the old code only filtered 4 bits, instead of accurately 
> > filtering the number range 0-9.
> >
> > Thanks,
> > Horace Lien
> >
> > -----Original Message-----
> > From: Kinney, Michael D <michael.d.kinney@intel.com>
> > Sent: Thursday, August 31, 2023 11:56 PM
> > To: devel@edk2.groups.io; Lien, HoraceX <horacex.lien@intel.com>
> > Cc: Liu, Zhiguang <zhiguang.liu@intel.com>; Bi, Dandan 
> > <dandan.bi@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, 
> > Zhichao <zhichao.gao@intel.com>; Kinney, Michael D 
> > <michael.d.kinney@intel.com>
> > Subject: RE: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix 
> > BcdRevision is not match with SMBIOS version
> >
> > Are mPrivateData.Smbios.MajorVersion and 
> > mPrivateData.Smbios.MinorVersion guaranteed to be in range 0..9?
> >
> > Mike
> >
> > > -----Original Message-----
> > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of 
> > > horacex.lien@intel.com
> > > Sent: Wednesday, August 30, 2023 2:13 AM
> > > To: devel@edk2.groups.io
> > > Cc: Lien, HoraceX <horacex.lien@intel.com>; Liu, Zhiguang 
> > > <zhiguang.liu@intel.com>; Bi, Dandan <dandan.bi@intel.com>; Zeng, 
> > > Star <star.zeng@intel.com>; Gao, Zhichao <zhichao.gao@intel.com>
> > > Subject: [edk2-devel] [PATCH] MdeModulePkg/SmbiosDxe: Fix 
> > > BcdRevision is not match with SMBIOS version
> > >
> > > From: HoraceX Lien <horacex.lien@intel.com>
> > >
> > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4544
> > >
> > > These value of Major/Minor version are updated from SMBIOS memory 
> > > data, but BCD Revision is updated from PCD PcdSmbiosVersion.
> > > We should also update PCD PcdSmbiosVersion from SMBIOS memory 
> > > data, to ensure that get consistent version value.
> > >
> > > Cc: Zhiguang Liu <zhiguang.liu@intel.com>
> > > Cc: Dandan Bi <dandan.bi@intel.com>
> > > Cc: Star Zeng <star.zeng@intel.com>
> > > Cc: Zhichao Gao <zhichao.gao@intel.com>
> > > Signed-off-by: HoraceX Lien <horacex.lien@intel.com>
> > > ---
> > >  MdeModulePkg/Universal/SmbiosDxe/SmbiosDxe.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/MdeModulePkg/Universal/SmbiosDxe/SmbiosDxe.c
> > > b/MdeModulePkg/Universal/SmbiosDxe/SmbiosDxe.c
> > > index 1a86e69d3c..e3f6215033 100644
> > > --- a/MdeModulePkg/Universal/SmbiosDxe/SmbiosDxe.c
> > > +++ b/MdeModulePkg/Universal/SmbiosDxe/SmbiosDxe.c
> > > @@ -1072,7 +1072,7 @@ SmbiosCreateTable (
> > >      DEBUG ((DEBUG_INFO, "SmbiosCreateTable: Initialize 32-bit 
> > > entry point structure\n"));
> > >
> > >      EntryPointStructureData.MajorVersion      =
> > > mPrivateData.Smbios.MajorVersion;
> > >
> > >      EntryPointStructureData.MinorVersion      =
> > > mPrivateData.Smbios.MinorVersion;
> > >
> > > -    EntryPointStructureData.SmbiosBcdRevision = (UINT8)((PcdGet16
> > > (PcdSmbiosVersion) >> 4) & 0xf0) | (UINT8)(PcdGet16
> > > (PcdSmbiosVersion) & 0x0f);
> > >
> > > +    EntryPointStructureData.SmbiosBcdRevision =
> > > (mPrivateData.Smbios.MajorVersion << 4) | 
> > > mPrivateData.Smbios.MinorVersion;
> > >
> > >      PhysicalAddress                           = 0xffffffff;
> > >
> > >      Status                                    = gBS->AllocatePages (
> > >
> > >
> > > AllocateMaxAddress,
> > >
> > > --
> > > 2.31.1.windows.1
> > >
> > >
> > >
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> >
> >
> > 
> >



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