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QemuQ35Pkg/SmmControl2Dxe: Drop S3 and Lock Box support
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Removes S3 and boot script related code to focus the module on simply
installing `Trigger()` and `Clear()` functionality for the SMM
Control protocol.

Signed-off-by: Michael Kubacki <Michael.kubacki@microsoft.com>
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makubacki committed Sep 24, 2024
1 parent 1f90578 commit b22b4e7
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Showing 6 changed files with 20 additions and 309 deletions.
6 changes: 1 addition & 5 deletions Platforms/QemuQ35Pkg/SmmControl2Dxe/MmControlPei.c
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Expand Up @@ -29,16 +29,12 @@
#include <Library/PciLib.h>
#include <Library/PeiServicesLib.h>
#include <Library/QemuFwCfgLib.h>
#include <Library/QemuFwCfgS3Lib.h>
#include <Ppi/MmControl.h>

#include "SmiFeatures.h"

//
// The absolute IO port address of the SMI Control and Enable Register. It is
// only used to carry information from the entry point function to the
// S3SaveState protocol installation callback, strictly before the runtime
// phase.
// The absolute IO port address of the SMI Control and Enable Register.
//
STATIC UINTN mSmiEnable;

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1 change: 0 additions & 1 deletion Platforms/QemuQ35Pkg/SmmControl2Dxe/MmControlPei.inf
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Expand Up @@ -52,7 +52,6 @@
PcdLib
PciLib
QemuFwCfgLib
QemuFwCfgS3Lib
PeimEntryPoint

[Ppis]
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121 changes: 7 additions & 114 deletions Platforms/QemuQ35Pkg/SmmControl2Dxe/SmiFeatures.c
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Expand Up @@ -3,6 +3,7 @@
accordingly.
Copyright (C) 2016-2017, Red Hat, Inc.
Copyright (c) Microsoft Corporation
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
Expand All @@ -13,7 +14,6 @@
#include <Library/MemoryAllocationLib.h>
#include <Library/PcdLib.h>
#include <Library/QemuFwCfgLib.h>
#include <Library/QemuFwCfgS3Lib.h>

#include "SmiFeatures.h"

Expand All @@ -35,41 +35,27 @@
//
#define ICH9_LPC_SMI_F_CPU_HOT_UNPLUG BIT2

//
// Provides a scratch buffer (allocated in EfiReservedMemoryType type memory)
// for the S3 boot script fragment to write to and read from.
//
#pragma pack (1)
typedef union {
UINT64 Features;
UINT8 FeaturesOk;
} SCRATCH_BUFFER;
#pragma pack ()

//
// These carry the selector keys of the "etc/smi/requested-features" and
// "etc/smi/features-ok" fw_cfg files from NegotiateSmiFeatures() to
// AppendFwCfgBootScript().
// "etc/smi/features-ok" fw_cfg files from NegotiateSmiFeatures().
//
STATIC FIRMWARE_CONFIG_ITEM mRequestedFeaturesItem;
STATIC FIRMWARE_CONFIG_ITEM mFeaturesOkItem;

//
// Carries the negotiated SMI features from NegotiateSmiFeatures() to
// AppendFwCfgBootScript().
// Holds the negotiated SMI features from NegotiateSmiFeatures().
//
STATIC UINT64 mSmiFeatures;

/**
Negotiate SMI features with QEMU.
@retval FALSE If SMI feature negotiation is not supported by QEMU. This is
not an error, it just means that SaveSmiFeatures() should not
be called.
@retval FALSE It is not an error if SMI feature negotiation is not supported
by QEMU. It just means the data cannot be used.
@retval TRUE SMI feature negotiation is supported, and it has completed
successfully as well. (Failure to negotiate is a fatal error
and the function never returns in that case.)
successfully as well (failure to negotiate is a fatal error
and the function never returns in that case).
**/
BOOLEAN
NegotiateSmiFeatures (
Expand Down Expand Up @@ -237,96 +223,3 @@ NegotiateSmiFeatures (
//
return FALSE;
}

/**
FW_CFG_BOOT_SCRIPT_CALLBACK_FUNCTION provided to QemuFwCfgS3Lib.
**/
STATIC
VOID
EFIAPI
AppendFwCfgBootScript (
IN OUT VOID *Context OPTIONAL,
IN OUT VOID *ExternalScratchBuffer
)
{
SCRATCH_BUFFER *ScratchBuffer;
RETURN_STATUS Status;

ScratchBuffer = ExternalScratchBuffer;

//
// Write the negotiated feature bitmap into "etc/smi/requested-features".
//
ScratchBuffer->Features = mSmiFeatures;
Status = QemuFwCfgS3ScriptWriteBytes (
mRequestedFeaturesItem,
sizeof ScratchBuffer->Features
);
if (RETURN_ERROR (Status)) {
goto FatalError;
}

//
// Read back "etc/smi/features-ok". This invokes the feature validation &
// lockdown. (The validation succeeded at first boot.)
//
Status = QemuFwCfgS3ScriptReadBytes (
mFeaturesOkItem,
sizeof ScratchBuffer->FeaturesOk
);
if (RETURN_ERROR (Status)) {
goto FatalError;
}

//
// If "etc/smi/features-ok" read as 1, we're good. Otherwise, hang the S3
// resume process.
//
Status = QemuFwCfgS3ScriptCheckValue (
&ScratchBuffer->FeaturesOk,
sizeof ScratchBuffer->FeaturesOk,
MAX_UINT8,
1
);
if (RETURN_ERROR (Status)) {
goto FatalError;
}

DEBUG ((
DEBUG_VERBOSE,
"%a: SMI feature negotiation boot script saved\n",
__FUNCTION__
));
return;

FatalError:
ASSERT (FALSE);
CpuDeadLoop ();
}

/**
Append a boot script fragment that will re-select the previously negotiated
SMI features during S3 resume.
**/
VOID
SaveSmiFeatures (
VOID
)
{
RETURN_STATUS Status;

//
// We are already running at TPL_CALLBACK, on the stack of
// OnS3SaveStateInstalled(). But that's okay, we can easily queue more
// notification functions while executing a notification function.
//
Status = QemuFwCfgS3CallWhenBootScriptReady (
AppendFwCfgBootScript,
NULL,
sizeof (SCRATCH_BUFFER)
);
if (RETURN_ERROR (Status)) {
ASSERT (FALSE);
CpuDeadLoop ();
}
}
21 changes: 5 additions & 16 deletions Platforms/QemuQ35Pkg/SmmControl2Dxe/SmiFeatures.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3,38 +3,27 @@
accordingly.
Copyright (C) 2016-2017, Red Hat, Inc.
Copyright (c) Microsoft Corporation
SPDX-License-Identifier: BSD-2-Clause-Patent
**/

#ifndef __SMI_FEATURES_H__
#define __SMI_FEATURES_H__

#include <Protocol/S3SaveState.h>

/**
Negotiate SMI features with QEMU.
@retval FALSE If SMI feature negotiation is not supported by QEMU. This is
not an error, it just means that SaveSmiFeatures() should not
be called.
@retval FALSE It is not an error if SMI feature negotiation is not supported
by QEMU. It just means the data cannot be used.
@retval TRUE SMI feature negotiation is supported, and it has completed
successfully as well. (Failure to negotiate is a fatal error
and the function never returns in that case.)
successfully as well (failure to negotiate is a fatal error
and the function never returns in that case).
**/
BOOLEAN
NegotiateSmiFeatures (
VOID
);

/**
Append a boot script fragment that will re-select the previously negotiated
SMI features during S3 resume.
**/
VOID
SaveSmiFeatures (
VOID
);

#endif
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