The PEI dispatcher handles PEIMs and embedded firmware volume images.
PEIMs are loaded and called (1), while embedded firmware volume images are
recursively scanned (2) for PEIMs and for further embedded firmware volume
images. FirmwareVolmeInfoPpiNotifyCallback() is the function directly
producing the newly detected entries for the dispatcher.
PeiDispatcher() [MdeModulePkg/Core/Pei/Dispatcher/Dispatcher.c]
(3) DepexSatisfied()
(4) PeiServicesFfsFindSectionData(DEPEX) [MdePkg/.../PeiServicesLib.c]
PeiFfsFindSectionData() [MdeModulePkg/Core/Pei/FwVol/FwVol.c]
PeiFfsFvPpiFindSectionByType()
PeiFfsFvPpiFindSectionByType2()
ProcessSection()
(5) Decompress() [MdeModulePkg/Core/DxeIplPeim/DxeLoad.c]
AllocatePages() [MdePkg/.../PeiMemoryAllocationLib]
if satisfied:
PeiFfsFvPpiGetFileInfo() [MdeModulePkg/Core/Pei/FwVol/FwVol.c]
if EFI_FV_FILETYPE_FIRMWARE_VOLUME_IMAGE:
(2) ProcessFvFile()
PeiServicesInstallFvInfo2Ppi() [MdePkg/.../PeiServicesLib]
InternalPeiServicesInstallFvInfoPpi()
PeiServicesInstallPpi()
FirmwareVolmeInfoPpiNotifyCallback() [.../FwVol.c]
ProcessFvFile()
...
else:
(1) PeiLoadImage()
PeiDispatcher checks for dependency expressions first (3), and the
type-dependent processing in (1) and (2) happens only if such a Depex is
satisfied (or absent).
Files of type EFI_FV_FILETYPE_FIRMWARE_VOLUME_IMAGE can have no Depex
sections, they are pure containers. DepexSatisfied() at (3) always returns
TRUE for them, so functionality is not directly harmed.
However, an EFI_FV_FILETYPE_FIRMWARE_VOLUME_IMAGE can be compressed. In
order to look up the (nonexistent) Depex section (4), the Decompress
routine (5) is called.
Unfortunately, the Decompress() routine allocates EfiBootServicesData
memory. This is not permitted on the S3 Resume path, but PeiDispatcher()
is part of the S3 Resume path.
The problem is triggered by OVMF's firmware structure:
FD.OVMF
FV.FVMAIN_COMPACT uncompressed
FV.MAINFV compressed with LzmaCompress
individual PEI modules uncompressed
FV.DXEFV compressed with PI_NONE
individual DXE modules uncompressed
FV.SECFV uncompressed
FV.MAINFV is decompressed by OVMF's SEC and is only exposed to the PEI
dispatcher in decompressed form, so that's not the problem. However
FV.DXEFV, which is a direct sibling of the PEIMs, is compressed (with the
PI_NONE === EFI_NOT_COMPRESSED compression subtype). This causes an
invalid EfiBootServicesData allocation during S3 Resume, inside the
useless Depex check.
Avoiding the allocation by restricting the Depex check in PeiDispatcher()
to PEIMs doesn't help: ProcessFvFile() under (2) triggers the same
allocation by calling PeiFfsFvPpiFindSectionByType2() -- it must
decompress the file in order to scan it.
Changing FV.DXEFV's encapsulation from COMPRESS to GUIDED won't help
either, because in that case ProcessSection() would want to call
EFI_PEI_GUIDED_SECTION_EXTRACTION_PPI.ExtractSection(), which again
allocates memory.
Solve this by flattening FV.MAINFV:
FD.OVMF
FV.FVMAIN_COMPACT uncompressed
FV.MAINFV compressed with LzmaCompress
individual PEI modules uncompressed
individual DXE modules uncompressed
FV.SECFV uncompressed
This way we avoid recursive processing, without hurting the efficiency of
the outermost compression (in FV.MAINFV).
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
---
OvmfPkg/OvmfPkgX64.fdf | 39 ++++++---------------------------------
1 file changed, 6 insertions(+), 33 deletions(-)
diff --git a/OvmfPkg/OvmfPkgX64.fdf b/OvmfPkg/OvmfPkgX64.fdf
index e435486..2508c22 100644
--- a/OvmfPkg/OvmfPkgX64.fdf
+++ b/OvmfPkg/OvmfPkgX64.fdf
@@ -250,6 +250,12 @@ APRIORI PEI {
INF MdeModulePkg/Universal/PCD/Pei/Pcd.inf
}
+APRIORI DXE {
+ INF MdeModulePkg/Universal/DevicePathDxe/DevicePathDxe.inf
+ INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
+ INF OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FvbServicesRuntimeDxe.inf
+}
+
#
# PEI Phase modules
#
@@ -261,39 +267,6 @@ INF MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
INF OvmfPkg/EmuSmmPei/EmuSmmPei.inf
INF UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf
-FILE FV_IMAGE = A4EF5A93-3F1B-4232-A1C4-F0910E6D1D9C {
- SECTION COMPRESS PI_NONE {
- SECTION FV_IMAGE = DXEFV
- }
-}
-
-################################################################################
-
-[FV.DXEFV]
-BlockSize = 0x10000
-FvAlignment = 16
-ERASE_POLARITY = 1
-MEMORY_MAPPED = TRUE
-STICKY_WRITE = TRUE
-LOCK_CAP = TRUE
-LOCK_STATUS = TRUE
-WRITE_DISABLED_CAP = TRUE
-WRITE_ENABLED_CAP = TRUE
-WRITE_STATUS = TRUE
-WRITE_LOCK_CAP = TRUE
-WRITE_LOCK_STATUS = TRUE
-READ_DISABLED_CAP = TRUE
-READ_ENABLED_CAP = TRUE
-READ_STATUS = TRUE
-READ_LOCK_CAP = TRUE
-READ_LOCK_STATUS = TRUE
-
-APRIORI DXE {
- INF MdeModulePkg/Universal/DevicePathDxe/DevicePathDxe.inf
- INF MdeModulePkg/Universal/PCD/Dxe/Pcd.inf
- INF OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FvbServicesRuntimeDxe.inf
-}
-
#
# DXE Phase modules
#
--
1.8.3.1
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