On 4/16/22 22:01, Min Xu wrote:
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.
CcProbe is introduced in this patch-set. It is called in
BaseIoLibIntrinsicSev instead of IsTdxGuest. There are 2 versions of
the CcProbeLib. Null instance of CcProbe always returns
CCGuestTypeNonEncrypted. Its OvmfPkg version checks the Ovmf work area
and returns the CC guest type.
In this patch-set another issue is fixed with CcProbe as well. If the
working guest is SEV and in the beginning of SecMain.c TdIsEnabled()
was called. At this point, exception handling is not established and
a CPUID instruction will generate a #VC and cause the booting SEV guest
to crash. Patch #7 is to fix this broken.
Code is at: https://github.com/mxu9/edk2/tree/cc_probe.v3
v3 changes:
- Fix the broken issue in SEV guest at SecMain.c. Please refer to
Patch #7.
v2 changes:
- Rename TdProbe to CcProbe to make the lib work for Confidential
Computing guests.
- Rename the GUEST_TYPE to CC_GUEST_TYPE and move it from
WorkArea.h@OvmfPkg to ConfidentialComputingGuestAttr.h@MdePkg.
This is because CcProbeLib is designed to return the CC Guest
type and the lib is located at MdePkg.
- Rename the CC_GUEST_TYPE's fields name to Camel style. See the
commit message in patch #1.
Cc: Michael D Kinney <michael.d.kin...@intel.com>
Cc: Liming Gao <gaolim...@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang....@intel.com>
Cc: James Bottomley <j...@linux.ibm.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Gerd Hoffmann <kra...@redhat.com>
Cc: Brijesh Singh <brijesh.si...@amd.com>
Cc: Erdem Aktas <erdemak...@google.com>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Signed-off-by: Min Xu <min.m...@intel.com>
After working around the PCI library issue (for which Min will be
submitting a patch), this series boots successfully for SEV, SEV-ES and
SEV-SNP when built as X64. I documented the issue that SEV has with
Ia32X64 in patch 5/7 and I'll have to decide what to do there. So...
Reviewed-by: Tom Lendacky <thomas.lenda...@amd.com>
Min Xu (7):
MdePkg: Add CC_GUEST_TYPE in ConfidentialComputingGuestAttr.h
OvmfPkg: Replace GUEST_TYPE with CC_GUEST_TYPE
MdePkg: Add CcProbeLib
OvmfPkg: Add CcProbeLib
OvmfPkg: Add CcProbeLib in *.dsc
MdePkg: Probe Cc guest in BaseIoLibIntrinsicSev
OvmfPkg: Call CcProbe in SecMain.c instead of TsIsEnabled
.../Include/ConfidentialComputingGuestAttr.h | 11 ++++++-
MdePkg/Include/Library/CcProbeLib.h | 26 ++++++++++++++++
.../BaseIoLibIntrinsicSev.inf | 1 +
.../BaseIoLibIntrinsic/IoLibInternalTdx.c | 13 ++------
.../Library/CcProbeLibNull/CcProbeLibNull.c | 26 ++++++++++++++++
.../Library/CcProbeLibNull/CcProbeLibNull.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/Include/WorkArea.h | 9 +-----
OvmfPkg/IntelTdx/IntelTdxX64.dsc | 1 +
OvmfPkg/IntelTdx/Sec/SecMain.c | 6 ++--
OvmfPkg/IntelTdx/Sec/SecMain.inf | 1 +
.../PeiMemEncryptSevLibInternal.c | 2 +-
.../SecMemEncryptSevLibInternal.c | 2 +-
OvmfPkg/Library/CcProbeLib/CcProbeLib.c | 31 +++++++++++++++++++
OvmfPkg/Library/CcProbeLib/CcProbeLib.inf | 25 +++++++++++++++
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgPei.c | 2 +-
OvmfPkg/Microvm/MicrovmX64.dsc | 1 +
OvmfPkg/OvmfPkgIa32.dsc | 1 +
OvmfPkg/OvmfPkgIa32X64.dsc | 1 +
OvmfPkg/OvmfPkgX64.dsc | 1 +
OvmfPkg/OvmfXen.dsc | 1 +
OvmfPkg/Sec/AmdSev.c | 2 +-
OvmfPkg/Sec/SecMain.c | 5 +--
OvmfPkg/Sec/SecMain.inf | 1 +
28 files changed, 170 insertions(+), 29 deletions(-)
create mode 100644 MdePkg/Include/Library/CcProbeLib.h
create mode 100644 MdePkg/Library/CcProbeLibNull/CcProbeLibNull.c
create mode 100644 MdePkg/Library/CcProbeLibNull/CcProbeLibNull.inf
create mode 100644 OvmfPkg/Library/CcProbeLib/CcProbeLib.c
create mode 100644 OvmfPkg/Library/CcProbeLib/CcProbeLib.inf
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