[edk2-devel] [PATCH 0/4] Introduce TdProbe in MdePkg

[Min Xu]

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3902

Bad IO performance in SEC phase is observed after TDX features was
introduced. (after commit b6b2de884864 - "MdePkg: Support mmio for
Tdx guest in BaseIoLibIntrinsic").

This is because IsTdxGuest() will be called in each MMIO operation.
It is trying to cache the result of the probe in the efi data segment.
However, that doesn't work in SEC, because the data segment is read only
(so the write seems to succeed but a read will always return the
original value), leading to us calling TdIsEnabled() check for every
mmio we do, which is causing the slowdown because it's very expensive.

TdProbe is introduced in this patch-set. It is called in
BaseIoLibIntrinsicSev instead of IsTdxGuest. There are 2 versions of the
TdProbeLib. Null instance of TdProbe always returns TD_PROBE_NON. Its
OvmfPkg version checks the Ovmf work area to determine the Td guest type.

Cc: Michael D Kinney <michael.d.kinney at intel.com>
Cc: Liming Gao <gaoliming at byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu at intel.com>
Cc: James Bottomley <jejb at linux.ibm.com>
Cc: James Bottomley <James.Bottomley at HansenPartnership.com>
Cc: Jiewen Yao <jiewen.yao at intel.com>
Cc: Gerd Hoffmann <kraxel at redhat.com>
Cc: Brijesh Singh <brijesh.singh at amd.com>
Cc: Erdem Aktas <erdemaktas at google.com>
Cc: Tom Lendacky <thomas.lendacky at amd.com>
Signed-off-by: Min Xu <min.m.xu at intel.com>

Min Xu (4):
  MdePkg: Add TdProbeLib
  OvmfPkg/IntelTdx: Add TdProbeLib
  MdePkg: Probe Td guest in BaseIoLibIntrinsicSev
  OvmfPkg: Add TdProbeLib in *.dsc

 MdePkg/Include/Library/TdProbeLib.h           | 26 +++++++++++++
 .../BaseIoLibIntrinsicSev.inf                 |  1 +
 .../BaseIoLibIntrinsic/IoLibInternalTdx.c     | 13 +------
 .../Library/TdProbeLibNull/TdProbeLibNull.c   | 25 ++++++++++++
 .../Library/TdProbeLibNull/TdProbeLibNull.inf | 21 ++++++++++
 MdePkg/MdePkg.dec                             |  5 +++
 MdePkg/MdePkg.dsc                             |  1 +
 OvmfPkg/AmdSev/AmdSevX64.dsc                  |  1 +
 OvmfPkg/Bhyve/BhyveX64.dsc                    |  1 +
 OvmfPkg/CloudHv/CloudHvX64.dsc                |  1 +
 OvmfPkg/IntelTdx/IntelTdxX64.dsc              |  1 +
 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.c      | 38 +++++++++++++++++++
 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.inf    | 25 ++++++++++++
 OvmfPkg/Microvm/MicrovmX64.dsc                |  1 +
 OvmfPkg/OvmfPkgIa32.dsc                       |  1 +
 OvmfPkg/OvmfPkgIa32X64.dsc                    |  1 +
 OvmfPkg/OvmfPkgX64.dsc                        |  1 +
 OvmfPkg/OvmfXen.dsc                           |  1 +
 18 files changed, 153 insertions(+), 11 deletions(-)
 create mode 100644 MdePkg/Include/Library/TdProbeLib.h
 create mode 100644 MdePkg/Library/TdProbeLibNull/TdProbeLibNull.c
 create mode 100644 MdePkg/Library/TdProbeLibNull/TdProbeLibNull.inf
 create mode 100644 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.c
 create mode 100644 OvmfPkg/IntelTdx/TdProbeLib/TdProbeLib.inf

-- 
2.29.2.windows.2



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