-----Original Message-----
From: Wu, Hao A
Sent: Friday, January 25, 2019 3:27 PM
To: Chen, Chen A <chen.a.c...@intel.com>; Gao, Liming <liming....@intel.com>;
edk2-devel@lists.01.org
Cc: Kinney, Michael D <michael.d.kin...@intel.com>; Zhang, Chao B
<chao.b.zh...@intel.com>
Subject: RE: [edk2] [PATCH 2/2] MdePkg/UefiGpt.h: Add new definition for enable
GPT support
> -----Original Message-----
> From: Chen, Chen A
> Sent: Friday, January 25, 2019 3:16 PM
> To: Wu, Hao A; edk2-devel@lists.01.org
> Cc: Kinney, Michael D; Zhang, Chao B; Gao, Liming
> Subject: RE: [edk2] [PATCH 2/2] MdePkg/UefiGpt.h: Add new definition
> for enable GPT support
>
>
>
> -----Original Message-----
> From: Wu, Hao A
> Sent: Friday, January 25, 2019 11:04 AM
> To: Chen, Chen A <chen.a.c...@intel.com>; edk2-devel@lists.01.org
> Cc: Kinney, Michael D <michael.d.kin...@intel.com>; Zhang, Chao B
> <chao.b.zh...@intel.com>; Gao, Liming <liming....@intel.com>
> Subject: RE: [edk2] [PATCH 2/2] MdePkg/UefiGpt.h: Add new definition
> for enable GPT support
>
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf
> > Of Chen A Chen
> > Sent: Thursday, January 17, 2019 10:03 AM
> > To: edk2-devel@lists.01.org
> > Cc: Kinney, Michael D; Zhang, Chao B; Gao, Liming
> > Subject: [edk2] [PATCH 2/2] MdePkg/UefiGpt.h: Add new definition for
> > enable GPT support
> >
> > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1470
> > This two new definitions are defined for GPT in FatPei diver.
> >
> > Cc: Liming Gao <liming....@intel.com>
> > Cc: Michael D Kinney <michael.d.kin...@intel.com>
> > Cc: Zhang Chao B <chao.b.zh...@intel.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Chen A Chen <chen.a.c...@intel.com>
> > ---
> > MdePkg/Include/Uefi/UefiGpt.h | 16 ++++++++++++++++
> > 1 file changed, 16 insertions(+)
> >
> > diff --git a/MdePkg/Include/Uefi/UefiGpt.h
> > b/MdePkg/Include/Uefi/UefiGpt.h index f635b05390..8665c8cbc9 100644
> > --- a/MdePkg/Include/Uefi/UefiGpt.h
> > +++ b/MdePkg/Include/Uefi/UefiGpt.h
> > @@ -24,9 +24,25 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF
> ANY KIND,
> > EITHER EXPRESS OR IMPLIED.
> > /// EFI Partition Table Signature: "EFI PART".
> > ///
> > #define EFI_PTAB_HEADER_ID SIGNATURE_64 ('E','F','I','
> > ','P','A','R','T')
> > +///
> > +/// Minimum bytes reserve for EFI entry array buffer.
> > +///
> > +#define GPT_PART_ENTRY_MIN_SIZE 16384
>
> May I know where this definition comes from?
> Does it come from the UEFI spec?
>
> Chen: The MACRO is not explicitly defined in UEFI Spec, But UEFI Spec
> specifies a minimum value for GPT entry araray.
Does it comes from the below content within the UEFI spec?
> A minimum of 16,384 bytes of space must be reserved for the GPT
> Partition Entry Array.
If so, I am not sure whether 'EFI_' prefix should be added before
'GPT_PART_ENTRY_MIN_SIZE'.
Liming, could you help to confirm?
Chen: I have no strong opinion on ' GPT_PART_ENTRY_MIN_SIZE' and
'EFI_GPT_PART_ENTRY_MIN_SIZE'.
>
> >
> > #pragma pack(1)
> >
> > +///
> > +/// MBR Partition Entry
> > +///
> > +typedef struct {
> > + UINT8 BootIndicator;
> > + UINT8 StartingCHS[3];
> > + UINT8 OSType;
> > + UINT8 EndingCHS[3];
> > + UINT32 StartingLBA;
> > + UINT32 SizeInLBA;
> > +} MBR_PARTITION_ENTRY;
> > +
>
> What about using the 'MBR_PARTITION_RECORD' definition within
> edk2/MdePkg/Include/IndustryStandard/Mbr.h
>
> and thus get rid of adding this one?
>
> Chen: This structure defined as the following format in Mbr.h
>
> typedef struct {
> ..
> UINT8 StartingLBA[4];
> UINT8 SizeInLBA[4];
> } MBR_PARTITION_RECORD;
>
> For StartingLBA, this field is represented the LBA, so I think it
> should be
> UINT32 type not an array type.
I do not get your point, what prevents you from getting the LBA information for
the byte array?
Chen: Yes, GPT DXE driver use UNPACK_UINT32 macro to extract UINT32 from
array. But I thought use UINT32 type get the value more directly.
Best Regards,
Hao Wu
>
> The same meaning is also for SizeInLba.
>
> Best Regards,
> Hao Wu
>
> > ///
> > /// GPT Partition Table Header.
> > ///
> > --
> > 2.16.2.windows.1
> >
> > _______________________________________________
> > edk2-devel mailing list
> > edk2-devel@lists.01.org
> > https://lists.01.org/mailman/listinfo/edk2-devel
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