Re: [PATCH 0/5] OvmfPkg: recognize an extended TSEG when QEMU offers it

[Jordan Justen <jordan.l.justen@intel.com>]

On 2017-06-08 10:13:28, Laszlo Ersek wrote:
> In <https://bugzilla.redhat.com/show_bug.cgi?id=1447027> we found that
> the SMM_REQUIRE build of OVMF cannot boot with as many VCPUs as we'd
> like, due to SMRAM exhaustion (even with the largest TSEG, 8MB).
> 
> Related thread on edk2-devel:
> <https://lists.01.org/pipermail/edk2-devel/2017-May/010371.html>.
> 
> The QEMU patch at
> <http://mid.mail-archive.com/20170608161013.17920-1-lersek@redhat.com>

This patch hasn't been merged to qemu yet, right? Would you propose
that we wait until this is merged to qemu master, or present in a qemu
release before merging the OVMF support? At what point does qemu
consider it an unchangable supported feature?

-Jordan

> adds a new device property / PCI config register to the Q35 board's DRAM
> controller. The property allows the user (and new Q35 machine types by
> default) to specify an arbitrary TSEG size (expressed as a number of
> megabytes). The register enables the firmware to query the size /
> availability of the feature. The extended size, when available, can be
> selected by writing the "11" bitmask to the ESMRAMC.TSEG_SZ register
> bit-field. This bitmask (similarly to the invented register's location
> in PCI config space) is defined as reserved in the original Q35/MCH
> spec.
> 
> This series adds support for the feature to OVMF. When an extended TSEG
> is offered, OVMF will choose it.
> 
> The first four patches extract Q35TsegSizeLib, centralizing the
> interpretation of ESMRAMC.TSEG_SZ between PlatformPei, SmmAccessPei and
> SmmAccess2Dxe. This subset of patches incurs no observable change in
> behavior.
> 
> The last patch implements the feature in Q35TsegSizeLib.
> 
> Repo:   https://github.com/lersek/edk2.git
> Branch: extended_tseg_bz1447027
> 
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> 
> Thanks
> Laszlo
> 
> Laszlo Ersek (5):
>   OvmfPkg: introduce Q35TsegSizeLib (class header and sole lib instance)
>   OvmfPkg/PlatformPei: rebase to Q35TsegSizeLib
>   OvmfPkg/SmmAccess: rebase code unique to SmmAccessPei to
>     Q35TsegSizeLib
>   OvmfPkg/SmmAccess: rebase shared PEIM/DXE code to Q35TsegSizeLib
>   OvmfPkg/Q35TsegSizeLib: recognize an extended TSEG when QEMU offers it
> 
>  OvmfPkg/Include/IndustryStandard/Q35MchIch9.h     |   4 +
>  OvmfPkg/Include/Library/Q35TsegSizeLib.h          |  74 +++++++
>  OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.c   | 230 ++++++++++++++++++++
>  OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf |  47 ++++
>  OvmfPkg/OvmfPkg.dec                               |  13 +-
>  OvmfPkg/OvmfPkgIa32.dsc                           |   1 +
>  OvmfPkg/OvmfPkgIa32X64.dsc                        |   1 +
>  OvmfPkg/OvmfPkgX64.dsc                            |   1 +
>  OvmfPkg/PlatformPei/MemDetect.c                   |   7 +-
>  OvmfPkg/PlatformPei/PlatformPei.inf               |   2 +-
>  OvmfPkg/SmmAccess/SmmAccess2Dxe.inf               |   1 +
>  OvmfPkg/SmmAccess/SmmAccessPei.c                  |   7 +-
>  OvmfPkg/SmmAccess/SmmAccessPei.inf                |   4 +-
>  OvmfPkg/SmmAccess/SmramInternal.c                 |  13 +-
>  14 files changed, 384 insertions(+), 21 deletions(-)
>  create mode 100644 OvmfPkg/Include/Library/Q35TsegSizeLib.h
>  create mode 100644 OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.c
>  create mode 100644 OvmfPkg/Library/Q35TsegSizeLib/Q35TsegSizeLib.inf
> 
> -- 
> 2.9.3
>