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From: "Ni, Ray" <ray.ni@intel.com>
To: Gerd Hoffmann <kraxel@redhat.com>, "Wu, Jiaxin" <jiaxin.wu@intel.com>
Cc: "devel@edk2.groups.io" <devel@edk2.groups.io>,
	"Dong, Eric" <eric.dong@intel.com>,
	"Zeng, Star" <star.zeng@intel.com>,
	Laszlo Ersek <lersek@redhat.com>,
	"Kumar, Rahul R" <rahul.r.kumar@intel.com>,
	"Kinney, Michael D" <michael.d.kinney@intel.com>,
	"Zimmer, Vincent" <vincent.zimmer@intel.com>
Subject: Re: [PATCH v3 1/5] UefiCpuPkg/SmmBaseHob.h: Add SMM Base HOB Data
Date: Wed, 18 Jan 2023 15:06:11 +0000	[thread overview]
Message-ID: <MN6PR11MB82446A36A4BFBB2E1C41893F8CC79@MN6PR11MB8244.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20230118111913.xgjlxdhngzwhvf76@sirius.home.kraxel.org>

Gerd,
In another mail with title "MdePkg: Remove Itanium leftover data structure",
we are discussing the HOB EFI_SEC_PLATFORM_INFORMATION_RECORD2 that helps
share the BIST information with CpuDxe driver.
That HOB is of format: <UINT32> ( <UINT32> <UINT32> ) +.
Very similar to the format of SMM_BASE_HOB_DATA: <UINT64> <UINT64>+

So, if we use a pattern here to remove the 8K CPU limitation, the same pattern will
be used by EFI_SEC_PLATFORM_INFORMATION_RECORD2 as well.

How about a new format as below? + Mike and Vincent for comments since the same
pattern may be used for EFI_SEC_PLATFORM_INFORMATION_RECORD3.

#pragma pack(1)
typedef struct {
  UINT32    CpuIndex;
  UINT32    NumberOfCpus;  // align to EFI_SEC_PLATFORM_INFORMATION_RECORD2.NumberOfCpus
  UINT64    SmBase[];
} SMM_BASE_HOB_DATA;
#pragma pack()

For system with less than 8K CPUs, one HOB is produced. CpuIndex is set to 0 indicating
the HOB describes the CPU from 0 to NumberOfCpus-1.

The HOB list may contains multiple such HOB instances each describing the information for
CPU from CpuIndex to CpuIndex + NumberOfCpus - 1.
The instance order in the HOB list is random so consumer cannot assume the CpuIndex
of first instance is 0.

Thanks,
Ray

> -----Original Message-----
> From: Gerd Hoffmann <kraxel@redhat.com>
> Sent: Wednesday, January 18, 2023 7:19 PM
> To: Wu, Jiaxin <jiaxin.wu@intel.com>
> Cc: devel@edk2.groups.io; Dong, Eric <eric.dong@intel.com>; Ni, Ray
> <ray.ni@intel.com>; Zeng, Star <star.zeng@intel.com>; Laszlo Ersek
> <lersek@redhat.com>; Kumar, Rahul R <rahul.r.kumar@intel.com>
> Subject: Re: [PATCH v3 1/5] UefiCpuPkg/SmmBaseHob.h: Add SMM Base HOB
> Data
> 
>   Hi,
> 
> > +#pragma pack(1)
> > +typedef struct {
> > +  ///
> > +  /// Describes the Number of all max supported processors.
> > +  ///
> > +  UINT64    NumberOfProcessors;
> > +  ///
> > +  /// Pointer to SmBase address for each Processors.
> > +  ///
> > +  UINT64    SmBase[];
> > +} SMM_BASE_HOB_DATA;
> > +#pragma pack()
> 
> HOBs are limited to 64k in size.  So this can by design support at most
> 8191 processors.  Adding such a interface to edk2 doesn't look like a
> good idea to me.  It probably is not that far off that we'll hit that
> limit given that high-end systems with 1024+ processors exist today.
> 
> take care,
>   Gerd


  reply	other threads:[~2023-01-18 15:06 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-18  9:56 [PATCH v3 0/5] Simplify SMM Relocation Process Wu, Jiaxin
2023-01-18  9:56 ` [PATCH v3 1/5] UefiCpuPkg/SmmBaseHob.h: Add SMM Base HOB Data Wu, Jiaxin
2023-01-18 11:19   ` Gerd Hoffmann
2023-01-18 15:06     ` Ni, Ray [this message]
2023-01-19  7:13       ` Gerd Hoffmann
2023-01-29  5:08         ` Wu, Jiaxin
2023-02-01 13:02           ` Gerd Hoffmann
2023-01-20  8:21       ` Laszlo Ersek
2023-01-29  5:24         ` Wu, Jiaxin
2023-02-01 13:14           ` Gerd Hoffmann
2023-02-02  0:44             ` Wu, Jiaxin
2023-02-02  3:54             ` [edk2-devel] " Ni, Ray
2023-02-02  3:52         ` Ni, Ray
2023-02-02 12:51           ` Gerd Hoffmann
2023-02-02 22:29             ` [edk2-devel] " Brian J. Johnson
2023-02-03  3:14               ` Ni, Ray
2023-02-03  7:54                 ` Gerd Hoffmann
2023-02-03 13:22                   ` Wu, Jiaxin
2023-02-03 13:31                     ` Ni, Ray
2023-02-03 15:00                     ` Gerd Hoffmann
2023-01-18  9:56 ` [PATCH v3 2/5] UefiCpuPkg/PiSmmCpuDxeSmm: Fix invalid InitializeMpSyncData call Wu, Jiaxin
2023-01-18  9:56 ` [PATCH v3 3/5] UefiCpuPkg/PiSmmCpuDxeSmm: Consume SMM Base Hob for SmBase info Wu, Jiaxin
2023-01-18 12:02   ` Gerd Hoffmann
2023-01-29  6:14     ` [edk2-devel] " Wu, Jiaxin
2023-01-18  9:56 ` [PATCH v3 4/5] UefiCpuPkg/SmmCpuFeaturesLib: Skip SMBASE configuration Wu, Jiaxin
2023-01-18  9:56 ` [PATCH v3 5/5] OvmfPkg/SmmCpuFeaturesLib: " Wu, Jiaxin
2023-01-18 12:19   ` Gerd Hoffmann
2023-01-18 14:37     ` Ni, Ray
2023-01-19  7:53       ` Gerd Hoffmann
2023-01-29  5:47         ` Wu, Jiaxin
2023-02-01 13:40           ` Gerd Hoffmann
2023-02-02  1:41             ` Wu, Jiaxin
2023-02-02  9:00               ` Gerd Hoffmann
2023-02-02 11:47                 ` Laszlo Ersek
2023-02-02 12:24                   ` Gerd Hoffmann
2023-02-03  3:05                     ` Wu, Jiaxin
2023-02-03  2:47                   ` Wu, Jiaxin
2023-02-03  3:45                   ` Ni, Ray
2023-02-03  7:31                     ` Gerd Hoffmann
2023-02-03  7:43                       ` Ni, Ray
2023-02-03  8:49                         ` Gerd Hoffmann
2023-02-03 11:18                         ` Wu, Jiaxin
     [not found] ` <173B5EAF72B992BD.14781@groups.io>
2023-02-03  8:59   ` [edk2-devel] " Wu, Jiaxin
2023-02-03  9:04     ` Gerd Hoffmann
2023-02-03 11:15       ` Wu, Jiaxin

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