[mirror_edk2.git] / OvmfPkg / CpuHotplugSmm / CpuHotplug.c

/** @file\r
  Root SMI handler for VCPU hotplug SMIs.\r
\r
  Copyright (c) 2020, Red Hat, Inc.\r
\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
**/\r
\r
#include <CpuHotPlugData.h>                  // CPU_HOT_PLUG_DATA\r
#include <IndustryStandard/Q35MchIch9.h>     // ICH9_APM_CNT\r
#include <IndustryStandard/QemuCpuHotplug.h> // QEMU_CPUHP_CMD_GET_PENDING\r
#include <Library/BaseLib.h>                 // CpuDeadLoop()\r
#include <Library/DebugLib.h>                // ASSERT()\r
#include <Library/MmServicesTableLib.h>      // gMmst\r
#include <Library/PcdLib.h>                  // PcdGetBool()\r
#include <Library/SafeIntLib.h>              // SafeUintnSub()\r
#include <Protocol/MmCpuIo.h>                // EFI_MM_CPU_IO_PROTOCOL\r
#include <Protocol/SmmCpuService.h>          // EFI_SMM_CPU_SERVICE_PROTOCOL\r
#include <Uefi/UefiBaseType.h>               // EFI_STATUS\r
\r
#include "ApicId.h"                          // APIC_ID\r
#include "QemuCpuhp.h"                       // QemuCpuhpWriteCpuSelector()\r
\r
//\r
// We use this protocol for accessing IO Ports.\r
//\r
STATIC EFI_MM_CPU_IO_PROTOCOL *mMmCpuIo;\r
//\r
// The following protocol is used to report the addition or removal of a CPU to\r
// the SMM CPU driver (PiSmmCpuDxeSmm).\r
//\r
STATIC EFI_SMM_CPU_SERVICE_PROTOCOL *mMmCpuService;\r
//\r
// This structure is a communication side-channel between the\r
// EFI_SMM_CPU_SERVICE_PROTOCOL consumer (i.e., this driver) and provider\r
// (i.e., PiSmmCpuDxeSmm).\r
//\r
STATIC CPU_HOT_PLUG_DATA *mCpuHotPlugData;\r
//\r
// SMRAM arrays for fetching the APIC IDs of processors with pending events (of\r
// known event types), for the time of just one MMI.\r
//\r
// The lifetimes of these arrays match that of this driver only because we\r
// don't want to allocate SMRAM at OS runtime, and potentially fail (or\r
// fragment the SMRAM map).\r
//\r
// These arrays provide room for ("possible CPU count" minus one) APIC IDs\r
// each, as we don't expect every possible CPU to appear, or disappear, in a\r
// single MMI. The numbers of used (populated) elements in the arrays are\r
// determined on every MMI separately.\r
//\r
STATIC APIC_ID *mPluggedApicIds;\r
STATIC APIC_ID *mToUnplugApicIds;\r
//\r
// Represents the registration of the CPU Hotplug MMI handler.\r
//\r
STATIC EFI_HANDLE mDispatchHandle;\r
\r
\r
/**\r
  CPU Hotplug MMI handler function.\r
\r
  This is a root MMI handler.\r
\r
  @param[in] DispatchHandle      The unique handle assigned to this handler by\r
                                 EFI_MM_SYSTEM_TABLE.MmiHandlerRegister().\r
\r
  @param[in] Context             Context passed in by\r
                                 EFI_MM_SYSTEM_TABLE.MmiManage(). Due to\r
                                 CpuHotplugMmi() being a root MMI handler,\r
                                 Context is ASSERT()ed to be NULL.\r
\r
  @param[in,out] CommBuffer      Ignored, due to CpuHotplugMmi() being a root\r
                                 MMI handler.\r
\r
  @param[in,out] CommBufferSize  Ignored, due to CpuHotplugMmi() being a root\r
                                 MMI handler.\r
\r
  @retval EFI_SUCCESS                       The MMI was handled and the MMI\r
                                            source was quiesced. When returned\r
                                            by a non-root MMI handler,\r
                                            EFI_SUCCESS terminates the\r
                                            processing of MMI handlers in\r
                                            EFI_MM_SYSTEM_TABLE.MmiManage().\r
                                            For a root MMI handler (i.e., for\r
                                            the present function too),\r
                                            EFI_SUCCESS behaves identically to\r
                                            EFI_WARN_INTERRUPT_SOURCE_QUIESCED,\r
                                            as further root MMI handlers are\r
                                            going to be called by\r
                                            EFI_MM_SYSTEM_TABLE.MmiManage()\r
                                            anyway.\r
\r
  @retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED  The MMI source has been quiesced,\r
                                              but other handlers should still\r
                                              be called.\r
\r
  @retval EFI_WARN_INTERRUPT_SOURCE_PENDING   The MMI source is still pending,\r
                                              and other handlers should still\r
                                              be called.\r
\r
  @retval EFI_INTERRUPT_PENDING               The MMI source could not be\r
                                              quiesced.\r
**/\r
STATIC\r
EFI_STATUS\r
EFIAPI\r
CpuHotplugMmi (\r
  IN EFI_HANDLE DispatchHandle,\r
  IN CONST VOID *Context        OPTIONAL,\r
  IN OUT VOID   *CommBuffer     OPTIONAL,\r
  IN OUT UINTN  *CommBufferSize OPTIONAL\r
  )\r
{\r
  EFI_STATUS Status;\r
  UINT8      ApmControl;\r
  UINT32     PluggedCount;\r
  UINT32     ToUnplugCount;\r
\r
  //\r
  // Assert that we are entering this function due to our root MMI handler\r
  // registration.\r
  //\r
  ASSERT (DispatchHandle == mDispatchHandle);\r
  //\r
  // When MmiManage() is invoked to process root MMI handlers, the caller (the\r
  // MM Core) is expected to pass in a NULL Context. MmiManage() then passes\r
  // the same NULL Context to individual handlers.\r
  //\r
  ASSERT (Context == NULL);\r
  //\r
  // Read the MMI command value from the APM Control Port, to see if this is an\r
  // MMI we should care about.\r
  //\r
  Status = mMmCpuIo->Io.Read (mMmCpuIo, MM_IO_UINT8, ICH9_APM_CNT, 1,\r
                          &ApmControl);\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((DEBUG_ERROR, "%a: failed to read ICH9_APM_CNT: %r\n", __FUNCTION__,\r
      Status));\r
    //\r
    // We couldn't even determine if the MMI was for us or not.\r
    //\r
    goto Fatal;\r
  }\r
\r
  if (ApmControl != ICH9_APM_CNT_CPU_HOTPLUG) {\r
    //\r
    // The MMI is not for us.\r
    //\r
    return EFI_WARN_INTERRUPT_SOURCE_QUIESCED;\r
  }\r
\r
  //\r
  // Collect the CPUs with pending events.\r
  //\r
  Status = QemuCpuhpCollectApicIds (\r
             mMmCpuIo,\r
             mCpuHotPlugData->ArrayLength,     // PossibleCpuCount\r
             mCpuHotPlugData->ArrayLength - 1, // ApicIdCount\r
             mPluggedApicIds,\r
             &PluggedCount,\r
             mToUnplugApicIds,\r
             &ToUnplugCount\r
             );\r
  if (EFI_ERROR (Status)) {\r
    goto Fatal;\r
  }\r
  if (ToUnplugCount > 0) {\r
    DEBUG ((DEBUG_ERROR, "%a: hot-unplug is not supported yet\n",\r
      __FUNCTION__));\r
    goto Fatal;\r
  }\r
\r
  //\r
  // We've handled this MMI.\r
  //\r
  return EFI_SUCCESS;\r
\r
Fatal:\r
  ASSERT (FALSE);\r
  CpuDeadLoop ();\r
  //\r
  // We couldn't handle this MMI.\r
  //\r
  return EFI_INTERRUPT_PENDING;\r
}\r
\r
\r
//\r
// Entry point function of this driver.\r
//\r
EFI_STATUS\r
EFIAPI\r
CpuHotplugEntry (\r
  IN EFI_HANDLE       ImageHandle,\r
  IN EFI_SYSTEM_TABLE *SystemTable\r
  )\r
{\r
  EFI_STATUS Status;\r
  UINTN      Size;\r
\r
  //\r
  // This module should only be included when SMM support is required.\r
  //\r
  ASSERT (FeaturePcdGet (PcdSmmSmramRequire));\r
  //\r
  // This driver depends on the dynamically detected "SMRAM at default SMBASE"\r
  // feature.\r
  //\r
  if (!PcdGetBool (PcdQ35SmramAtDefaultSmbase)) {\r
    return EFI_UNSUPPORTED;\r
  }\r
\r
  //\r
  // Errors from here on are fatal; we cannot allow the boot to proceed if we\r
  // can't set up this driver to handle CPU hotplug.\r
  //\r
  // First, collect the protocols needed later. All of these protocols are\r
  // listed in our module DEPEX.\r
  //\r
  Status = gMmst->MmLocateProtocol (&gEfiMmCpuIoProtocolGuid,\r
                    NULL /* Registration */, (VOID **)&mMmCpuIo);\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((DEBUG_ERROR, "%a: locate MmCpuIo: %r\n", __FUNCTION__, Status));\r
    goto Fatal;\r
  }\r
  Status = gMmst->MmLocateProtocol (&gEfiSmmCpuServiceProtocolGuid,\r
                    NULL /* Registration */, (VOID **)&mMmCpuService);\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((DEBUG_ERROR, "%a: locate MmCpuService: %r\n", __FUNCTION__,\r
      Status));\r
    goto Fatal;\r
  }\r
\r
  //\r
  // Our DEPEX on EFI_SMM_CPU_SERVICE_PROTOCOL guarantees that PiSmmCpuDxeSmm\r
  // has pointed PcdCpuHotPlugDataAddress to CPU_HOT_PLUG_DATA in SMRAM.\r
  //\r
  mCpuHotPlugData = (VOID *)(UINTN)PcdGet64 (PcdCpuHotPlugDataAddress);\r
  if (mCpuHotPlugData == NULL) {\r
    Status = EFI_NOT_FOUND;\r
    DEBUG ((DEBUG_ERROR, "%a: CPU_HOT_PLUG_DATA: %r\n", __FUNCTION__, Status));\r
    goto Fatal;\r
  }\r
  //\r
  // If the possible CPU count is 1, there's nothing for this driver to do.\r
  //\r
  if (mCpuHotPlugData->ArrayLength == 1) {\r
    return EFI_UNSUPPORTED;\r
  }\r
  //\r
  // Allocate the data structures that depend on the possible CPU count.\r
  //\r
  if (RETURN_ERROR (SafeUintnSub (mCpuHotPlugData->ArrayLength, 1, &Size)) ||\r
      RETURN_ERROR (SafeUintnMult (sizeof (APIC_ID), Size, &Size))) {\r
    Status = EFI_ABORTED;\r
    DEBUG ((DEBUG_ERROR, "%a: invalid CPU_HOT_PLUG_DATA\n", __FUNCTION__));\r
    goto Fatal;\r
  }\r
  Status = gMmst->MmAllocatePool (EfiRuntimeServicesData, Size,\r
                    (VOID **)&mPluggedApicIds);\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((DEBUG_ERROR, "%a: MmAllocatePool(): %r\n", __FUNCTION__, Status));\r
    goto Fatal;\r
  }\r
  Status = gMmst->MmAllocatePool (EfiRuntimeServicesData, Size,\r
                    (VOID **)&mToUnplugApicIds);\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((DEBUG_ERROR, "%a: MmAllocatePool(): %r\n", __FUNCTION__, Status));\r
    goto ReleasePluggedApicIds;\r
  }\r
\r
  //\r
  // Sanity-check the CPU hotplug interface.\r
  //\r
  // Both of the following features are part of QEMU 5.0, introduced primarily\r
  // in commit range 3e08b2b9cb64..3a61c8db9d25:\r
  //\r
  // (a) the QEMU_CPUHP_CMD_GET_ARCH_ID command of the modern CPU hotplug\r
  //     interface,\r
  //\r
  // (b) the "SMRAM at default SMBASE" feature.\r
  //\r
  // From these, (b) is restricted to 5.0+ machine type versions, while (a)\r
  // does not depend on machine type version. Because we ensured the stricter\r
  // condition (b) through PcdQ35SmramAtDefaultSmbase above, the (a)\r
  // QEMU_CPUHP_CMD_GET_ARCH_ID command must now be available too. While we\r
  // can't verify the presence of precisely that command, we can still verify\r
  // (sanity-check) that the modern interface is active, at least.\r
  //\r
  // Consult the "Typical usecases | Detecting and enabling modern CPU hotplug\r
  // interface" section in QEMU's "docs/specs/acpi_cpu_hotplug.txt", on the\r
  // following.\r
  //\r
  QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);\r
  QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);\r
  QemuCpuhpWriteCommand (mMmCpuIo, QEMU_CPUHP_CMD_GET_PENDING);\r
  if (QemuCpuhpReadCommandData2 (mMmCpuIo) != 0) {\r
    Status = EFI_NOT_FOUND;\r
    DEBUG ((DEBUG_ERROR, "%a: modern CPU hotplug interface: %r\n",\r
      __FUNCTION__, Status));\r
    goto ReleaseToUnplugApicIds;\r
  }\r
\r
  //\r
  // Register the handler for the CPU Hotplug MMI.\r
  //\r
  Status = gMmst->MmiHandlerRegister (\r
                    CpuHotplugMmi,\r
                    NULL,            // HandlerType: root MMI handler\r
                    &mDispatchHandle\r
                    );\r
  if (EFI_ERROR (Status)) {\r
    DEBUG ((DEBUG_ERROR, "%a: MmiHandlerRegister(): %r\n", __FUNCTION__,\r
      Status));\r
    goto ReleaseToUnplugApicIds;\r
  }\r
\r
  return EFI_SUCCESS;\r
\r
ReleaseToUnplugApicIds:\r
  gMmst->MmFreePool (mToUnplugApicIds);\r
  mToUnplugApicIds = NULL;\r
\r
ReleasePluggedApicIds:\r
  gMmst->MmFreePool (mPluggedApicIds);\r
  mPluggedApicIds = NULL;\r
\r
Fatal:\r
  ASSERT (FALSE);\r
  CpuDeadLoop ();\r
  return Status;\r
}\r
Commit	Line	Data
17efae27 LE	1	/** @file\r
	2	Root SMI handler for VCPU hotplug SMIs.\r
	3	\r
	4	Copyright (c) 2020, Red Hat, Inc.\r
	5	\r
	6	SPDX-License-Identifier: BSD-2-Clause-Patent\r
	7	**/\r
	8	\r
17cb8ddb	9	#include <CpuHotPlugData.h> // CPU_HOT_PLUG_DATA\r
17efae27	10	#include <IndustryStandard/Q35MchIch9.h> // ICH9_APM_CNT\r
f668e788	11	#include <IndustryStandard/QemuCpuHotplug.h> // QEMU_CPUHP_CMD_GET_PENDING\r
17efae27 LE	12	#include <Library/BaseLib.h> // CpuDeadLoop()\r
	13	#include <Library/DebugLib.h> // ASSERT()\r
	14	#include <Library/MmServicesTableLib.h> // gMmst\r
	15	#include <Library/PcdLib.h> // PcdGetBool()\r
17cb8ddb	16	#include <Library/SafeIntLib.h> // SafeUintnSub()\r
17efae27	17	#include <Protocol/MmCpuIo.h> // EFI_MM_CPU_IO_PROTOCOL\r
17cb8ddb	18	#include <Protocol/SmmCpuService.h> // EFI_SMM_CPU_SERVICE_PROTOCOL\r
17efae27 LE	19	#include <Uefi/UefiBaseType.h> // EFI_STATUS\r
17efae27 LE	20	\r
17cb8ddb	21	#include "ApicId.h" // APIC_ID\r
f668e788 LE	22	#include "QemuCpuhp.h" // QemuCpuhpWriteCpuSelector()\r
f668e788 LE	23	\r
17efae27 LE	24	//\r
	25	// We use this protocol for accessing IO Ports.\r
	26	//\r
	27	STATIC EFI_MM_CPU_IO_PROTOCOL *mMmCpuIo;\r
	28	//\r
17cb8ddb LE	29	// The following protocol is used to report the addition or removal of a CPU to\r
	30	// the SMM CPU driver (PiSmmCpuDxeSmm).\r
	31	//\r
	32	STATIC EFI_SMM_CPU_SERVICE_PROTOCOL *mMmCpuService;\r
	33	//\r
	34	// This structure is a communication side-channel between the\r
	35	// EFI_SMM_CPU_SERVICE_PROTOCOL consumer (i.e., this driver) and provider\r
	36	// (i.e., PiSmmCpuDxeSmm).\r
	37	//\r
	38	STATIC CPU_HOT_PLUG_DATA *mCpuHotPlugData;\r
	39	//\r
	40	// SMRAM arrays for fetching the APIC IDs of processors with pending events (of\r
	41	// known event types), for the time of just one MMI.\r
	42	//\r
	43	// The lifetimes of these arrays match that of this driver only because we\r
	44	// don't want to allocate SMRAM at OS runtime, and potentially fail (or\r
	45	// fragment the SMRAM map).\r
	46	//\r
	47	// These arrays provide room for ("possible CPU count" minus one) APIC IDs\r
	48	// each, as we don't expect every possible CPU to appear, or disappear, in a\r
	49	// single MMI. The numbers of used (populated) elements in the arrays are\r
	50	// determined on every MMI separately.\r
	51	//\r
	52	STATIC APIC_ID *mPluggedApicIds;\r
	53	STATIC APIC_ID *mToUnplugApicIds;\r
	54	//\r
17efae27 LE	55	// Represents the registration of the CPU Hotplug MMI handler.\r
	56	//\r
	57	STATIC EFI_HANDLE mDispatchHandle;\r
	58	\r
	59	\r
	60	/**\r
	61	CPU Hotplug MMI handler function.\r
	62	\r
	63	This is a root MMI handler.\r
	64	\r
	65	@param[in] DispatchHandle The unique handle assigned to this handler by\r
	66	EFI_MM_SYSTEM_TABLE.MmiHandlerRegister().\r
	67	\r
	68	@param[in] Context Context passed in by\r
	69	EFI_MM_SYSTEM_TABLE.MmiManage(). Due to\r
	70	CpuHotplugMmi() being a root MMI handler,\r
	71	Context is ASSERT()ed to be NULL.\r
	72	\r
	73	@param[in,out] CommBuffer Ignored, due to CpuHotplugMmi() being a root\r
	74	MMI handler.\r
	75	\r
	76	@param[in,out] CommBufferSize Ignored, due to CpuHotplugMmi() being a root\r
	77	MMI handler.\r
	78	\r
	79	@retval EFI_SUCCESS The MMI was handled and the MMI\r
	80	source was quiesced. When returned\r
	81	by a non-root MMI handler,\r
	82	EFI_SUCCESS terminates the\r
	83	processing of MMI handlers in\r
	84	EFI_MM_SYSTEM_TABLE.MmiManage().\r
	85	For a root MMI handler (i.e., for\r
	86	the present function too),\r
	87	EFI_SUCCESS behaves identically to\r
	88	EFI_WARN_INTERRUPT_SOURCE_QUIESCED,\r
	89	as further root MMI handlers are\r
	90	going to be called by\r
	91	EFI_MM_SYSTEM_TABLE.MmiManage()\r
	92	anyway.\r
	93	\r
	94	@retval EFI_WARN_INTERRUPT_SOURCE_QUIESCED The MMI source has been quiesced,\r
	95	but other handlers should still\r
	96	be called.\r
	97	\r
	98	@retval EFI_WARN_INTERRUPT_SOURCE_PENDING The MMI source is still pending,\r
	99	and other handlers should still\r
	100	be called.\r
	101	\r
	102	@retval EFI_INTERRUPT_PENDING The MMI source could not be\r
	103	quiesced.\r
	104	**/\r
	105	STATIC\r
	106	EFI_STATUS\r
	107	EFIAPI\r
	108	CpuHotplugMmi (\r
	109	IN EFI_HANDLE DispatchHandle,\r
	110	IN CONST VOID *Context OPTIONAL,\r
	111	IN OUT VOID *CommBuffer OPTIONAL,\r
	112	IN OUT UINTN *CommBufferSize OPTIONAL\r
	113	)\r
	114	{\r
	115	EFI_STATUS Status;\r
	116	UINT8 ApmControl;\r
17cb8ddb LE	117	UINT32 PluggedCount;\r
17cb8ddb LE	118	UINT32 ToUnplugCount;\r
17efae27 LE	119	\r
	120	//\r
	121	// Assert that we are entering this function due to our root MMI handler\r
	122	// registration.\r
	123	//\r
	124	ASSERT (DispatchHandle == mDispatchHandle);\r
	125	//\r
	126	// When MmiManage() is invoked to process root MMI handlers, the caller (the\r
	127	// MM Core) is expected to pass in a NULL Context. MmiManage() then passes\r
	128	// the same NULL Context to individual handlers.\r
	129	//\r
	130	ASSERT (Context == NULL);\r
	131	//\r
	132	// Read the MMI command value from the APM Control Port, to see if this is an\r
	133	// MMI we should care about.\r
	134	//\r
	135	Status = mMmCpuIo->Io.Read (mMmCpuIo, MM_IO_UINT8, ICH9_APM_CNT, 1,\r
	136	&ApmControl);\r
	137	if (EFI_ERROR (Status)) {\r
	138	DEBUG ((DEBUG_ERROR, "%a: failed to read ICH9_APM_CNT: %r\n", __FUNCTION__,\r
	139	Status));\r
	140	//\r
	141	// We couldn't even determine if the MMI was for us or not.\r
	142	//\r
	143	goto Fatal;\r
	144	}\r
	145	\r
	146	if (ApmControl != ICH9_APM_CNT_CPU_HOTPLUG) {\r
	147	//\r
	148	// The MMI is not for us.\r
	149	//\r
	150	return EFI_WARN_INTERRUPT_SOURCE_QUIESCED;\r
	151	}\r
	152	\r
17cb8ddb LE	153	//\r
	154	// Collect the CPUs with pending events.\r
	155	//\r
	156	Status = QemuCpuhpCollectApicIds (\r
	157	mMmCpuIo,\r
	158	mCpuHotPlugData->ArrayLength, // PossibleCpuCount\r
	159	mCpuHotPlugData->ArrayLength - 1, // ApicIdCount\r
	160	mPluggedApicIds,\r
	161	&PluggedCount,\r
	162	mToUnplugApicIds,\r
	163	&ToUnplugCount\r
	164	);\r
	165	if (EFI_ERROR (Status)) {\r
	166	goto Fatal;\r
	167	}\r
	168	if (ToUnplugCount > 0) {\r
	169	DEBUG ((DEBUG_ERROR, "%a: hot-unplug is not supported yet\n",\r
	170	__FUNCTION__));\r
	171	goto Fatal;\r
	172	}\r
	173	\r
17efae27 LE	174	//\r
	175	// We've handled this MMI.\r
	176	//\r
	177	return EFI_SUCCESS;\r
	178	\r
	179	Fatal:\r
	180	ASSERT (FALSE);\r
	181	CpuDeadLoop ();\r
	182	//\r
	183	// We couldn't handle this MMI.\r
	184	//\r
	185	return EFI_INTERRUPT_PENDING;\r
	186	}\r
	187	\r
	188	\r
	189	//\r
	190	// Entry point function of this driver.\r
	191	//\r
	192	EFI_STATUS\r
	193	EFIAPI\r
	194	CpuHotplugEntry (\r
	195	IN EFI_HANDLE ImageHandle,\r
	196	IN EFI_SYSTEM_TABLE *SystemTable\r
	197	)\r
	198	{\r
	199	EFI_STATUS Status;\r
17cb8ddb	200	UINTN Size;\r
17efae27 LE	201	\r
	202	//\r
	203	// This module should only be included when SMM support is required.\r
	204	//\r
	205	ASSERT (FeaturePcdGet (PcdSmmSmramRequire));\r
	206	//\r
	207	// This driver depends on the dynamically detected "SMRAM at default SMBASE"\r
	208	// feature.\r
	209	//\r
	210	if (!PcdGetBool (PcdQ35SmramAtDefaultSmbase)) {\r
	211	return EFI_UNSUPPORTED;\r
	212	}\r
	213	\r
	214	//\r
	215	// Errors from here on are fatal; we cannot allow the boot to proceed if we\r
	216	// can't set up this driver to handle CPU hotplug.\r
	217	//\r
	218	// First, collect the protocols needed later. All of these protocols are\r
	219	// listed in our module DEPEX.\r
	220	//\r
	221	Status = gMmst->MmLocateProtocol (&gEfiMmCpuIoProtocolGuid,\r
	222	NULL /* Registration /, (VOID *)&mMmCpuIo);\r
	223	if (EFI_ERROR (Status)) {\r
	224	DEBUG ((DEBUG_ERROR, "%a: locate MmCpuIo: %r\n", __FUNCTION__, Status));\r
	225	goto Fatal;\r
	226	}\r
17cb8ddb LE	227	Status = gMmst->MmLocateProtocol (&gEfiSmmCpuServiceProtocolGuid,\r
	228	NULL /* Registration /, (VOID *)&mMmCpuService);\r
	229	if (EFI_ERROR (Status)) {\r
	230	DEBUG ((DEBUG_ERROR, "%a: locate MmCpuService: %r\n", __FUNCTION__,\r
	231	Status));\r
	232	goto Fatal;\r
	233	}\r
	234	\r
	235	//\r
	236	// Our DEPEX on EFI_SMM_CPU_SERVICE_PROTOCOL guarantees that PiSmmCpuDxeSmm\r
	237	// has pointed PcdCpuHotPlugDataAddress to CPU_HOT_PLUG_DATA in SMRAM.\r
	238	//\r
	239	mCpuHotPlugData = (VOID *)(UINTN)PcdGet64 (PcdCpuHotPlugDataAddress);\r
	240	if (mCpuHotPlugData == NULL) {\r
	241	Status = EFI_NOT_FOUND;\r
	242	DEBUG ((DEBUG_ERROR, "%a: CPU_HOT_PLUG_DATA: %r\n", __FUNCTION__, Status));\r
	243	goto Fatal;\r
	244	}\r
	245	//\r
	246	// If the possible CPU count is 1, there's nothing for this driver to do.\r
	247	//\r
	248	if (mCpuHotPlugData->ArrayLength == 1) {\r
	249	return EFI_UNSUPPORTED;\r
	250	}\r
	251	//\r
	252	// Allocate the data structures that depend on the possible CPU count.\r
	253	//\r
	254	if (RETURN_ERROR (SafeUintnSub (mCpuHotPlugData->ArrayLength, 1, &Size)) \|\|\r
	255	RETURN_ERROR (SafeUintnMult (sizeof (APIC_ID), Size, &Size))) {\r
	256	Status = EFI_ABORTED;\r
	257	DEBUG ((DEBUG_ERROR, "%a: invalid CPU_HOT_PLUG_DATA\n", __FUNCTION__));\r
	258	goto Fatal;\r
	259	}\r
	260	Status = gMmst->MmAllocatePool (EfiRuntimeServicesData, Size,\r
	261	(VOID **)&mPluggedApicIds);\r
	262	if (EFI_ERROR (Status)) {\r
	263	DEBUG ((DEBUG_ERROR, "%a: MmAllocatePool(): %r\n", __FUNCTION__, Status));\r
	264	goto Fatal;\r
	265	}\r
	266	Status = gMmst->MmAllocatePool (EfiRuntimeServicesData, Size,\r
	267	(VOID **)&mToUnplugApicIds);\r
	268	if (EFI_ERROR (Status)) {\r
	269	DEBUG ((DEBUG_ERROR, "%a: MmAllocatePool(): %r\n", __FUNCTION__, Status));\r
	270	goto ReleasePluggedApicIds;\r
	271	}\r
17efae27	272	\r
f668e788 LE	273	//\r
	274	// Sanity-check the CPU hotplug interface.\r
	275	//\r
	276	// Both of the following features are part of QEMU 5.0, introduced primarily\r
	277	// in commit range 3e08b2b9cb64..3a61c8db9d25:\r
	278	//\r
	279	// (a) the QEMU_CPUHP_CMD_GET_ARCH_ID command of the modern CPU hotplug\r
	280	// interface,\r
	281	//\r
	282	// (b) the "SMRAM at default SMBASE" feature.\r
	283	//\r
	284	// From these, (b) is restricted to 5.0+ machine type versions, while (a)\r
	285	// does not depend on machine type version. Because we ensured the stricter\r
	286	// condition (b) through PcdQ35SmramAtDefaultSmbase above, the (a)\r
	287	// QEMU_CPUHP_CMD_GET_ARCH_ID command must now be available too. While we\r
	288	// can't verify the presence of precisely that command, we can still verify\r
	289	// (sanity-check) that the modern interface is active, at least.\r
	290	//\r
	291	// Consult the "Typical usecases \| Detecting and enabling modern CPU hotplug\r
	292	// interface" section in QEMU's "docs/specs/acpi_cpu_hotplug.txt", on the\r
	293	// following.\r
	294	//\r
	295	QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);\r
	296	QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);\r
	297	QemuCpuhpWriteCommand (mMmCpuIo, QEMU_CPUHP_CMD_GET_PENDING);\r
	298	if (QemuCpuhpReadCommandData2 (mMmCpuIo) != 0) {\r
	299	Status = EFI_NOT_FOUND;\r
	300	DEBUG ((DEBUG_ERROR, "%a: modern CPU hotplug interface: %r\n",\r
	301	__FUNCTION__, Status));\r
17cb8ddb	302	goto ReleaseToUnplugApicIds;\r
f668e788 LE	303	}\r
f668e788 LE	304	\r
17efae27 LE	305	//\r
	306	// Register the handler for the CPU Hotplug MMI.\r
	307	//\r
	308	Status = gMmst->MmiHandlerRegister (\r
	309	CpuHotplugMmi,\r
	310	NULL, // HandlerType: root MMI handler\r
	311	&mDispatchHandle\r
	312	);\r
	313	if (EFI_ERROR (Status)) {\r
	314	DEBUG ((DEBUG_ERROR, "%a: MmiHandlerRegister(): %r\n", __FUNCTION__,\r
	315	Status));\r
17cb8ddb	316	goto ReleaseToUnplugApicIds;\r
17efae27 LE	317	}\r
	318	\r
	319	return EFI_SUCCESS;\r
	320	\r
17cb8ddb LE	321	ReleaseToUnplugApicIds:\r
	322	gMmst->MmFreePool (mToUnplugApicIds);\r
	323	mToUnplugApicIds = NULL;\r
	324	\r
	325	ReleasePluggedApicIds:\r
	326	gMmst->MmFreePool (mPluggedApicIds);\r
	327	mPluggedApicIds = NULL;\r
	328	\r
17efae27 LE	329	Fatal:\r
	330	ASSERT (FALSE);\r
	331	CpuDeadLoop ();\r
	332	return Status;\r
	333	}\r