[mirror_edk2.git] / OvmfPkg / SmmControl2Dxe / SmiFeatures.c

/**@file\r
  Negotiate SMI features with QEMU, and configure UefiCpuPkg/PiSmmCpuDxeSmm\r
  accordingly.\r
\r
  Copyright (C) 2016-2017, Red Hat, Inc.\r
\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
**/\r
\r
#include <Library/BaseLib.h>\r
#include <Library/DebugLib.h>\r
#include <Library/MemEncryptSevLib.h>\r
#include <Library/MemoryAllocationLib.h>\r
#include <Library/PcdLib.h>\r
#include <Library/QemuFwCfgLib.h>\r
#include <Library/QemuFwCfgS3Lib.h>\r
\r
#include "SmiFeatures.h"\r
\r
//\r
// The following bit value stands for "broadcast SMI" in the\r
// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.\r
//\r
#define ICH9_LPC_SMI_F_BROADCAST BIT0\r
//\r
// The following bit value stands for "enable CPU hotplug, and inject an SMI\r
// with control value ICH9_APM_CNT_CPU_HOTPLUG upon hotplug", in the\r
// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.\r
//\r
#define ICH9_LPC_SMI_F_CPU_HOTPLUG BIT1\r
//\r
// The following bit value stands for "enable CPU hot-unplug, and inject an SMI\r
// with control value ICH9_APM_CNT_CPU_HOTPLUG upon hot-unplug", in the\r
// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.\r
//\r
#define ICH9_LPC_SMI_F_CPU_HOT_UNPLUG BIT2\r
\r
//\r
// Provides a scratch buffer (allocated in EfiReservedMemoryType type memory)\r
// for the S3 boot script fragment to write to and read from.\r
//\r
#pragma pack (1)\r
typedef union {\r
  UINT64 Features;\r
  UINT8  FeaturesOk;\r
} SCRATCH_BUFFER;\r
#pragma pack ()\r
\r
//\r
// These carry the selector keys of the "etc/smi/requested-features" and\r
// "etc/smi/features-ok" fw_cfg files from NegotiateSmiFeatures() to\r
// AppendFwCfgBootScript().\r
//\r
STATIC FIRMWARE_CONFIG_ITEM mRequestedFeaturesItem;\r
STATIC FIRMWARE_CONFIG_ITEM mFeaturesOkItem;\r
\r
//\r
// Carries the negotiated SMI features from NegotiateSmiFeatures() to\r
// AppendFwCfgBootScript().\r
//\r
STATIC UINT64 mSmiFeatures;\r
\r
/**\r
  Negotiate SMI features with QEMU.\r
\r
  @retval FALSE  If SMI feature negotiation is not supported by QEMU. This is\r
                 not an error, it just means that SaveSmiFeatures() should not\r
                 be called.\r
\r
  @retval TRUE   SMI feature negotiation is supported, and it has completed\r
                 successfully as well. (Failure to negotiate is a fatal error\r
                 and the function never returns in that case.)\r
**/\r
BOOLEAN\r
NegotiateSmiFeatures (\r
  VOID\r
  )\r
{\r
  FIRMWARE_CONFIG_ITEM SupportedFeaturesItem;\r
  UINTN                SupportedFeaturesSize;\r
  UINTN                RequestedFeaturesSize;\r
  UINTN                FeaturesOkSize;\r
  UINT64               RequestedFeaturesMask;\r
\r
  //\r
  // Look up the fw_cfg files used for feature negotiation. The selector keys\r
  // of "etc/smi/requested-features" and "etc/smi/features-ok" are saved\r
  // statically. If the files are missing, then QEMU doesn't support SMI\r
  // feature negotiation.\r
  //\r
  if (RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/supported-features",\r
                      &SupportedFeaturesItem, &SupportedFeaturesSize)) ||\r
      RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/requested-features",\r
                      &mRequestedFeaturesItem, &RequestedFeaturesSize)) ||\r
      RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/features-ok",\r
                      &mFeaturesOkItem, &FeaturesOkSize))) {\r
    DEBUG ((DEBUG_INFO, "%a: SMI feature negotiation unavailable\n",\r
      __FUNCTION__));\r
    return FALSE;\r
  }\r
\r
  //\r
  // If the files are present but their sizes disagree with us, that's a fatal\r
  // error (we can't trust the behavior of SMIs either way).\r
  //\r
  if (SupportedFeaturesSize != sizeof mSmiFeatures ||\r
      RequestedFeaturesSize != sizeof mSmiFeatures ||\r
      FeaturesOkSize != sizeof (UINT8)) {\r
    DEBUG ((DEBUG_ERROR, "%a: size mismatch in feature negotiation\n",\r
      __FUNCTION__));\r
    goto FatalError;\r
  }\r
\r
  //\r
  // Get the features supported by the host.\r
  //\r
  QemuFwCfgSelectItem (SupportedFeaturesItem);\r
  QemuFwCfgReadBytes (sizeof mSmiFeatures, &mSmiFeatures);\r
\r
  //\r
  // We want broadcast SMI, SMI on CPU hotplug, SMI on CPU hot-unplug\r
  // and nothing else.\r
  //\r
  RequestedFeaturesMask = ICH9_LPC_SMI_F_BROADCAST;\r
  if (!MemEncryptSevIsEnabled ()) {\r
    //\r
    // For now, we only support hotplug with SEV disabled.\r
    //\r
    RequestedFeaturesMask |= ICH9_LPC_SMI_F_CPU_HOTPLUG;\r
    RequestedFeaturesMask |= ICH9_LPC_SMI_F_CPU_HOT_UNPLUG;\r
  }\r
  mSmiFeatures &= RequestedFeaturesMask;\r
  QemuFwCfgSelectItem (mRequestedFeaturesItem);\r
  QemuFwCfgWriteBytes (sizeof mSmiFeatures, &mSmiFeatures);\r
\r
  //\r
  // Invoke feature validation in QEMU. If the selection is accepted, the\r
  // features will be locked down. If the selection is rejected, feature\r
  // negotiation remains open; however we don't know what to do in that case,\r
  // so that's a fatal error.\r
  //\r
  QemuFwCfgSelectItem (mFeaturesOkItem);\r
  if (QemuFwCfgRead8 () != 1) {\r
    DEBUG ((DEBUG_ERROR, "%a: negotiation failed for feature bitmap 0x%Lx\n",\r
      __FUNCTION__, mSmiFeatures));\r
    goto FatalError;\r
  }\r
\r
  if ((mSmiFeatures & ICH9_LPC_SMI_F_BROADCAST) == 0) {\r
    //\r
    // If we can't get broadcast SMIs from QEMU, that's acceptable too,\r
    // although not optimal.\r
    //\r
    DEBUG ((DEBUG_INFO, "%a: SMI broadcast unavailable\n", __FUNCTION__));\r
  } else {\r
    //\r
    // Configure the traditional AP sync / SMI delivery mode for\r
    // PiSmmCpuDxeSmm. Effectively, restore the UefiCpuPkg defaults, from which\r
    // the original QEMU behavior (i.e., unicast SMI) used to differ.\r
    //\r
    if (RETURN_ERROR (PcdSet64S (PcdCpuSmmApSyncTimeout, 1000000)) ||\r
        RETURN_ERROR (PcdSet8S (PcdCpuSmmSyncMode, 0x00))) {\r
      DEBUG ((DEBUG_ERROR, "%a: PiSmmCpuDxeSmm PCD configuration failed\n",\r
        __FUNCTION__));\r
      goto FatalError;\r
    }\r
    DEBUG ((DEBUG_INFO, "%a: using SMI broadcast\n", __FUNCTION__));\r
  }\r
\r
  if ((mSmiFeatures & ICH9_LPC_SMI_F_CPU_HOTPLUG) == 0) {\r
    DEBUG ((DEBUG_INFO, "%a: CPU hotplug not negotiated\n", __FUNCTION__));\r
  } else {\r
    DEBUG ((DEBUG_INFO, "%a: CPU hotplug with SMI negotiated\n",\r
      __FUNCTION__));\r
  }\r
\r
  if ((mSmiFeatures & ICH9_LPC_SMI_F_CPU_HOT_UNPLUG) == 0) {\r
    DEBUG ((DEBUG_INFO, "%a: CPU hot-unplug not negotiated\n", __FUNCTION__));\r
  } else {\r
    DEBUG ((DEBUG_INFO, "%a: CPU hot-unplug with SMI negotiated\n",\r
      __FUNCTION__));\r
  }\r
\r
  //\r
  // Negotiation successful (although we may not have gotten the optimal\r
  // feature set).\r
  //\r
  return TRUE;\r
\r
FatalError:\r
  ASSERT (FALSE);\r
  CpuDeadLoop ();\r
  //\r
  // Keep the compiler happy.\r
  //\r
  return FALSE;\r
}\r
\r
/**\r
  FW_CFG_BOOT_SCRIPT_CALLBACK_FUNCTION provided to QemuFwCfgS3Lib.\r
**/\r
STATIC\r
VOID\r
EFIAPI\r
AppendFwCfgBootScript (\r
  IN OUT VOID *Context,              OPTIONAL\r
  IN OUT VOID *ExternalScratchBuffer\r
  )\r
{\r
  SCRATCH_BUFFER *ScratchBuffer;\r
  RETURN_STATUS  Status;\r
\r
  ScratchBuffer = ExternalScratchBuffer;\r
\r
  //\r
  // Write the negotiated feature bitmap into "etc/smi/requested-features".\r
  //\r
  ScratchBuffer->Features = mSmiFeatures;\r
  Status = QemuFwCfgS3ScriptWriteBytes (mRequestedFeaturesItem,\r
             sizeof ScratchBuffer->Features);\r
  if (RETURN_ERROR (Status)) {\r
    goto FatalError;\r
  }\r
\r
  //\r
  // Read back "etc/smi/features-ok". This invokes the feature validation &\r
  // lockdown. (The validation succeeded at first boot.)\r
  //\r
  Status = QemuFwCfgS3ScriptReadBytes (mFeaturesOkItem,\r
             sizeof ScratchBuffer->FeaturesOk);\r
  if (RETURN_ERROR (Status)) {\r
    goto FatalError;\r
  }\r
\r
  //\r
  // If "etc/smi/features-ok" read as 1, we're good. Otherwise, hang the S3\r
  // resume process.\r
  //\r
  Status = QemuFwCfgS3ScriptCheckValue (&ScratchBuffer->FeaturesOk,\r
             sizeof ScratchBuffer->FeaturesOk, MAX_UINT8, 1);\r
  if (RETURN_ERROR (Status)) {\r
    goto FatalError;\r
  }\r
\r
  DEBUG ((DEBUG_VERBOSE, "%a: SMI feature negotiation boot script saved\n",\r
    __FUNCTION__));\r
  return;\r
\r
FatalError:\r
  ASSERT (FALSE);\r
  CpuDeadLoop ();\r
}\r
\r
\r
/**\r
  Append a boot script fragment that will re-select the previously negotiated\r
  SMI features during S3 resume.\r
**/\r
VOID\r
SaveSmiFeatures (\r
  VOID\r
  )\r
{\r
  RETURN_STATUS Status;\r
\r
  //\r
  // We are already running at TPL_CALLBACK, on the stack of\r
  // OnS3SaveStateInstalled(). But that's okay, we can easily queue more\r
  // notification functions while executing a notification function.\r
  //\r
  Status = QemuFwCfgS3CallWhenBootScriptReady (AppendFwCfgBootScript, NULL,\r
             sizeof (SCRATCH_BUFFER));\r
  if (RETURN_ERROR (Status)) {\r
    ASSERT (FALSE);\r
    CpuDeadLoop ();\r
  }\r
}\r
Commit	Line	Data
a316d7ac LE	1	/**@file\r
	2	Negotiate SMI features with QEMU, and configure UefiCpuPkg/PiSmmCpuDxeSmm\r
	3	accordingly.\r
	4	\r
	5	Copyright (C) 2016-2017, Red Hat, Inc.\r
	6	\r
b26f0cf9	7	SPDX-License-Identifier: BSD-2-Clause-Patent\r
a316d7ac LE	8	**/\r
	9	\r
	10	#include <Library/BaseLib.h>\r
	11	#include <Library/DebugLib.h>\r
5ba203b5	12	#include <Library/MemEncryptSevLib.h>\r
a316d7ac LE	13	#include <Library/MemoryAllocationLib.h>\r
	14	#include <Library/PcdLib.h>\r
	15	#include <Library/QemuFwCfgLib.h>\r
36a6aa6c	16	#include <Library/QemuFwCfgS3Lib.h>\r
a316d7ac LE	17	\r
	18	#include "SmiFeatures.h"\r
	19	\r
	20	//\r
	21	// The following bit value stands for "broadcast SMI" in the\r
	22	// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.\r
	23	//\r
	24	#define ICH9_LPC_SMI_F_BROADCAST BIT0\r
5ba203b5 LE	25	//\r
	26	// The following bit value stands for "enable CPU hotplug, and inject an SMI\r
	27	// with control value ICH9_APM_CNT_CPU_HOTPLUG upon hotplug", in the\r
	28	// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.\r
	29	//\r
	30	#define ICH9_LPC_SMI_F_CPU_HOTPLUG BIT1\r
f3bdfc41 AA	31	//\r
	32	// The following bit value stands for "enable CPU hot-unplug, and inject an SMI\r
	33	// with control value ICH9_APM_CNT_CPU_HOTPLUG upon hot-unplug", in the\r
	34	// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.\r
	35	//\r
	36	#define ICH9_LPC_SMI_F_CPU_HOT_UNPLUG BIT2\r
a316d7ac LE	37	\r
	38	//\r
	39	// Provides a scratch buffer (allocated in EfiReservedMemoryType type memory)\r
36a6aa6c	40	// for the S3 boot script fragment to write to and read from.\r
a316d7ac LE	41	//\r
a316d7ac LE	42	#pragma pack (1)\r
36a6aa6c LE	43	typedef union {\r
	44	UINT64 Features;\r
	45	UINT8 FeaturesOk;\r
a316d7ac LE	46	} SCRATCH_BUFFER;\r
	47	#pragma pack ()\r
	48	\r
	49	//\r
	50	// These carry the selector keys of the "etc/smi/requested-features" and\r
	51	// "etc/smi/features-ok" fw_cfg files from NegotiateSmiFeatures() to\r
36a6aa6c	52	// AppendFwCfgBootScript().\r
a316d7ac LE	53	//\r
	54	STATIC FIRMWARE_CONFIG_ITEM mRequestedFeaturesItem;\r
	55	STATIC FIRMWARE_CONFIG_ITEM mFeaturesOkItem;\r
	56	\r
	57	//\r
	58	// Carries the negotiated SMI features from NegotiateSmiFeatures() to\r
36a6aa6c	59	// AppendFwCfgBootScript().\r
a316d7ac LE	60	//\r
	61	STATIC UINT64 mSmiFeatures;\r
	62	\r
	63	/**\r
	64	Negotiate SMI features with QEMU.\r
	65	\r
	66	@retval FALSE If SMI feature negotiation is not supported by QEMU. This is\r
	67	not an error, it just means that SaveSmiFeatures() should not\r
	68	be called.\r
	69	\r
	70	@retval TRUE SMI feature negotiation is supported, and it has completed\r
	71	successfully as well. (Failure to negotiate is a fatal error\r
	72	and the function never returns in that case.)\r
	73	**/\r
	74	BOOLEAN\r
	75	NegotiateSmiFeatures (\r
	76	VOID\r
	77	)\r
	78	{\r
	79	FIRMWARE_CONFIG_ITEM SupportedFeaturesItem;\r
	80	UINTN SupportedFeaturesSize;\r
	81	UINTN RequestedFeaturesSize;\r
	82	UINTN FeaturesOkSize;\r
5ba203b5	83	UINT64 RequestedFeaturesMask;\r
a316d7ac LE	84	\r
	85	//\r
	86	// Look up the fw_cfg files used for feature negotiation. The selector keys\r
	87	// of "etc/smi/requested-features" and "etc/smi/features-ok" are saved\r
	88	// statically. If the files are missing, then QEMU doesn't support SMI\r
	89	// feature negotiation.\r
	90	//\r
	91	if (RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/supported-features",\r
	92	&SupportedFeaturesItem, &SupportedFeaturesSize)) \|\|\r
	93	RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/requested-features",\r
	94	&mRequestedFeaturesItem, &RequestedFeaturesSize)) \|\|\r
	95	RETURN_ERROR (QemuFwCfgFindFile ("etc/smi/features-ok",\r
	96	&mFeaturesOkItem, &FeaturesOkSize))) {\r
	97	DEBUG ((DEBUG_INFO, "%a: SMI feature negotiation unavailable\n",\r
	98	__FUNCTION__));\r
	99	return FALSE;\r
	100	}\r
	101	\r
	102	//\r
	103	// If the files are present but their sizes disagree with us, that's a fatal\r
	104	// error (we can't trust the behavior of SMIs either way).\r
	105	//\r
	106	if (SupportedFeaturesSize != sizeof mSmiFeatures \|\|\r
	107	RequestedFeaturesSize != sizeof mSmiFeatures \|\|\r
	108	FeaturesOkSize != sizeof (UINT8)) {\r
	109	DEBUG ((DEBUG_ERROR, "%a: size mismatch in feature negotiation\n",\r
	110	__FUNCTION__));\r
	111	goto FatalError;\r
	112	}\r
	113	\r
	114	//\r
	115	// Get the features supported by the host.\r
	116	//\r
	117	QemuFwCfgSelectItem (SupportedFeaturesItem);\r
	118	QemuFwCfgReadBytes (sizeof mSmiFeatures, &mSmiFeatures);\r
	119	\r
	120	//\r
f3bdfc41 AA	121	// We want broadcast SMI, SMI on CPU hotplug, SMI on CPU hot-unplug\r
f3bdfc41 AA	122	// and nothing else.\r
a316d7ac	123	//\r
5ba203b5 LE	124	RequestedFeaturesMask = ICH9_LPC_SMI_F_BROADCAST;\r
	125	if (!MemEncryptSevIsEnabled ()) {\r
	126	//\r
	127	// For now, we only support hotplug with SEV disabled.\r
	128	//\r
	129	RequestedFeaturesMask \|= ICH9_LPC_SMI_F_CPU_HOTPLUG;\r
f3bdfc41	130	RequestedFeaturesMask \|= ICH9_LPC_SMI_F_CPU_HOT_UNPLUG;\r
5ba203b5 LE	131	}\r
5ba203b5 LE	132	mSmiFeatures &= RequestedFeaturesMask;\r
a316d7ac LE	133	QemuFwCfgSelectItem (mRequestedFeaturesItem);\r
	134	QemuFwCfgWriteBytes (sizeof mSmiFeatures, &mSmiFeatures);\r
	135	\r
	136	//\r
	137	// Invoke feature validation in QEMU. If the selection is accepted, the\r
	138	// features will be locked down. If the selection is rejected, feature\r
	139	// negotiation remains open; however we don't know what to do in that case,\r
	140	// so that's a fatal error.\r
	141	//\r
	142	QemuFwCfgSelectItem (mFeaturesOkItem);\r
	143	if (QemuFwCfgRead8 () != 1) {\r
	144	DEBUG ((DEBUG_ERROR, "%a: negotiation failed for feature bitmap 0x%Lx\n",\r
	145	__FUNCTION__, mSmiFeatures));\r
	146	goto FatalError;\r
	147	}\r
	148	\r
	149	if ((mSmiFeatures & ICH9_LPC_SMI_F_BROADCAST) == 0) {\r
	150	//\r
	151	// If we can't get broadcast SMIs from QEMU, that's acceptable too,\r
	152	// although not optimal.\r
	153	//\r
	154	DEBUG ((DEBUG_INFO, "%a: SMI broadcast unavailable\n", __FUNCTION__));\r
	155	} else {\r
	156	//\r
	157	// Configure the traditional AP sync / SMI delivery mode for\r
	158	// PiSmmCpuDxeSmm. Effectively, restore the UefiCpuPkg defaults, from which\r
	159	// the original QEMU behavior (i.e., unicast SMI) used to differ.\r
	160	//\r
	161	if (RETURN_ERROR (PcdSet64S (PcdCpuSmmApSyncTimeout, 1000000)) \|\|\r
	162	RETURN_ERROR (PcdSet8S (PcdCpuSmmSyncMode, 0x00))) {\r
	163	DEBUG ((DEBUG_ERROR, "%a: PiSmmCpuDxeSmm PCD configuration failed\n",\r
	164	__FUNCTION__));\r
	165	goto FatalError;\r
	166	}\r
	167	DEBUG ((DEBUG_INFO, "%a: using SMI broadcast\n", __FUNCTION__));\r
	168	}\r
	169	\r
5ba203b5 LE	170	if ((mSmiFeatures & ICH9_LPC_SMI_F_CPU_HOTPLUG) == 0) {\r
	171	DEBUG ((DEBUG_INFO, "%a: CPU hotplug not negotiated\n", __FUNCTION__));\r
	172	} else {\r
	173	DEBUG ((DEBUG_INFO, "%a: CPU hotplug with SMI negotiated\n",\r
	174	__FUNCTION__));\r
	175	}\r
	176	\r
f3bdfc41 AA	177	if ((mSmiFeatures & ICH9_LPC_SMI_F_CPU_HOT_UNPLUG) == 0) {\r
	178	DEBUG ((DEBUG_INFO, "%a: CPU hot-unplug not negotiated\n", __FUNCTION__));\r
	179	} else {\r
	180	DEBUG ((DEBUG_INFO, "%a: CPU hot-unplug with SMI negotiated\n",\r
	181	__FUNCTION__));\r
	182	}\r
	183	\r
a316d7ac LE	184	//\r
	185	// Negotiation successful (although we may not have gotten the optimal\r
	186	// feature set).\r
	187	//\r
	188	return TRUE;\r
	189	\r
	190	FatalError:\r
	191	ASSERT (FALSE);\r
	192	CpuDeadLoop ();\r
	193	//\r
	194	// Keep the compiler happy.\r
	195	//\r
	196	return FALSE;\r
	197	}\r
	198	\r
	199	/**\r
36a6aa6c	200	FW_CFG_BOOT_SCRIPT_CALLBACK_FUNCTION provided to QemuFwCfgS3Lib.\r
a316d7ac	201	**/\r
36a6aa6c	202	STATIC\r
a316d7ac	203	VOID\r
36a6aa6c LE	204	EFIAPI\r
	205	AppendFwCfgBootScript (\r
	206	IN OUT VOID *Context, OPTIONAL\r
	207	IN OUT VOID *ExternalScratchBuffer\r
a316d7ac LE	208	)\r
	209	{\r
	210	SCRATCH_BUFFER *ScratchBuffer;\r
36a6aa6c	211	RETURN_STATUS Status;\r
a316d7ac	212	\r
36a6aa6c	213	ScratchBuffer = ExternalScratchBuffer;\r
a316d7ac LE	214	\r
a316d7ac LE	215	//\r
36a6aa6c	216	// Write the negotiated feature bitmap into "etc/smi/requested-features".\r
a316d7ac	217	//\r
36a6aa6c LE	218	ScratchBuffer->Features = mSmiFeatures;\r
	219	Status = QemuFwCfgS3ScriptWriteBytes (mRequestedFeaturesItem,\r
	220	sizeof ScratchBuffer->Features);\r
	221	if (RETURN_ERROR (Status)) {\r
a316d7ac LE	222	goto FatalError;\r
	223	}\r
	224	\r
	225	//\r
36a6aa6c LE	226	// Read back "etc/smi/features-ok". This invokes the feature validation &\r
36a6aa6c LE	227	// lockdown. (The validation succeeded at first boot.)\r
a316d7ac	228	//\r
36a6aa6c LE	229	Status = QemuFwCfgS3ScriptReadBytes (mFeaturesOkItem,\r
	230	sizeof ScratchBuffer->FeaturesOk);\r
	231	if (RETURN_ERROR (Status)) {\r
a316d7ac LE	232	goto FatalError;\r
	233	}\r
	234	\r
	235	//\r
36a6aa6c LE	236	// If "etc/smi/features-ok" read as 1, we're good. Otherwise, hang the S3\r
36a6aa6c LE	237	// resume process.\r
a316d7ac	238	//\r
36a6aa6c LE	239	Status = QemuFwCfgS3ScriptCheckValue (&ScratchBuffer->FeaturesOk,\r
	240	sizeof ScratchBuffer->FeaturesOk, MAX_UINT8, 1);\r
	241	if (RETURN_ERROR (Status)) {\r
a316d7ac LE	242	goto FatalError;\r
	243	}\r
	244	\r
36a6aa6c LE	245	DEBUG ((DEBUG_VERBOSE, "%a: SMI feature negotiation boot script saved\n",\r
36a6aa6c LE	246	__FUNCTION__));\r
a316d7ac LE	247	return;\r
	248	\r
	249	FatalError:\r
	250	ASSERT (FALSE);\r
	251	CpuDeadLoop ();\r
	252	}\r
36a6aa6c LE	253	\r
	254	\r
	255	/**\r
	256	Append a boot script fragment that will re-select the previously negotiated\r
	257	SMI features during S3 resume.\r
	258	**/\r
	259	VOID\r
	260	SaveSmiFeatures (\r
	261	VOID\r
	262	)\r
	263	{\r
	264	RETURN_STATUS Status;\r
	265	\r
	266	//\r
	267	// We are already running at TPL_CALLBACK, on the stack of\r
	268	// OnS3SaveStateInstalled(). But that's okay, we can easily queue more\r
	269	// notification functions while executing a notification function.\r
	270	//\r
	271	Status = QemuFwCfgS3CallWhenBootScriptReady (AppendFwCfgBootScript, NULL,\r
	272	sizeof (SCRATCH_BUFFER));\r
	273	if (RETURN_ERROR (Status)) {\r
	274	ASSERT (FALSE);\r
	275	CpuDeadLoop ();\r
	276	}\r
	277	}\r