During normal boot, when EFI_DXE_SMM_READY_TO_LOCK_PROTOCOL is installed
by platform BDS, the SMM IPL locks SMRAM (TSEG) through
EFI_SMM_ACCESS2_PROTOCOL.Lock(). See SmmIplReadyToLockEventNotify() in
"MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c".
During S3 resume, S3Resume2Pei locks SMRAM (TSEG) through
PEI_SMM_ACCESS_PPI.Lock(), before executing the boot script. See
S3ResumeExecuteBootScript() in
"UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c".
Those are precisely the places where the SMRAM at the default SMBASE
should be locked too. Add such an action to SmramAccessLock().
Notes:
- The SMRAM at the default SMBASE doesn't support the "closed and
unlocked" state (and so it can't be closed without locking it, and it
cannot be opened after closing it).
- The SMRAM at the default SMBASE isn't (and shouldn't) be exposed with
another EFI_SMRAM_DESCRIPTOR in the GetCapabilities() members of
EFI_SMM_ACCESS2_PROTOCOL / PEI_SMM_ACCESS_PPI. That's because the SMRAM
in question is not "general purpose"; it's only QEMU's solution to
protect the initial SMI handler from the OS, when a VCPU is hot-plugged.
Consequently, the state of the SMRAM at the default SMBASE is not
reflected in the "OpenState" / "LockState" fields of the protocol and
PPI.
- An alternative to extending SmramAccessLock() would be to register an
EFI_DXE_SMM_READY_TO_LOCK_PROTOCOL notify in SmmAccess2Dxe (for locking
at normal boot), and an EDKII_S3_SMM_INIT_DONE_GUID PPI notify in
SmmAccessPei (for locking at S3 resume).
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1512
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Message-Id: <20200129214412.2361-10-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
In one of the next patches we'll turn PcdQ35TsegMbytes into a dynamic PCD,
to be set by PlatformPei.
Jordan suggested to use gEfiPeiMemoryDiscoveredPpiGuid as SmmAccessPei's
DEPEX for making sure that PlatformPei sets the PCD before SmmAccessPei
consumes it. (PlatformPei installs the permanent PEI RAM.) Such a DEPEX is
supposed to mirror physical firmware, where anything related to SMRAM
cannot run before said platform's physical RAM is discovered (signaled by
the presence of gEfiPeiMemoryDiscoveredPpiGuid).
Introduce the InitQ35TsegMbytes() function and the "mQ35TsegMbytes" extern
variable to "SmramInternal.h" and "SmramInternal.c":
- Both SmmAccess modules (PEIM and DXE driver) are supposed to call
InitQ35TsegMbytes() in their respective entry point functions, saving
PcdQ35TsegMbytes into "mQ35TsegMbytes". This way dynamic PCD fetches can
be kept out of PEI_SMM_ACCESS_PPI and EFI_SMM_ACCESS2_PROTOCOL member
functions later (when we add support for extended TSEG size).
- We can thus replace the current PcdQ35TsegMbytes fetches in
SmmAccessPei's entry point function as well, with reads from
"mQ35TsegMbytes".
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
"MdeModulePkg/Library/SmmLockBoxLib/SmmLockBoxPeiLib.inf" is the
LockBoxLib instance with SMRAM access for the PEI phase.
Said library instance must, and can, access the LockBox data in SMRAM
directly if it is invoked before SMBASE relocation / SMI handler
installation. In that case, it only needs PEI_SMM_ACCESS_PPI from the
platform, and it doesn't depend on EFI_PEI_SMM_COMMUNICATION_PPI.
OVMF satisfies the description in SVN r18823 ("MdeModulePkg:
SmmLockBoxPeiLib: work without EFI_PEI_SMM_COMMUNICATION_PPI"): in OVMF,
only S3Resume2Pei links against SmmLockBoxPeiLib.
Therefore, introduce a PEIM that produces the PEI_SMM_ACCESS_PPI
interface, enabling SmmLockBoxPeiLib to work; we can omit including
"UefiCpuPkg/PiSmmCommunication/PiSmmCommunicationPei.inf".
The load / installation order of S3Resume2Pei and SmmAccessPei is
indifferent. SmmAccessPei produces the gEfiAcpiVariableGuid HOB during its
installation (which happens during PEI), but S3Resume2Pei accesses the HOB
only when the DXE IPL calls its S3RestoreConfig2 PPI member, as last act
of PEI.
MCH_SMRAM_D_LCK and MCH_ESMRAMC_T_EN are masked out the way they are, in
SmmAccessPeiEntryPoint() and SmramAccessOpen() respectively, in order to
prevent VS20xx from warning about the (otherwise fully intentional)
truncation in the UINT8 casts. (Warnings reported by Michael Kinney.)
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19040 6f19259b-4bc3-4df7-8a09-765794883524
Laszlo Ersek
Michael D Kinney