src/arch/aarch64/hypervisor/psci_handler.c - hafnium - Git at Google

 /*
  * Copyright 2019 The Hafnium Authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     https://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "psci_handler.h"

 #include <stdint.h>

 #include "hf/arch/types.h"

 #include "hf/api.h"
 #include "hf/cpu.h"
 #include "hf/dlog.h"
 #include "hf/panic.h"
 #include "hf/spci.h"
 #include "hf/vm.h"

 #include "psci.h"
 #include "smc.h"

 static uint32_t el3_psci_version;

 void cpu_entry(struct cpu *c);

 /* Performs arch specific boot time initialisation. */
 void arch_one_time_init(void)
 {
 	smc_res_t smc_res =
 		smc32(PSCI_VERSION, 0, 0, 0, 0, 0, 0, SMCCC_CALLER_HYPERVISOR);

 	el3_psci_version = smc_res.res0;

 	/* Check there's nothing unexpected about PSCI. */
 	switch (el3_psci_version) {
 	case PSCI_VERSION_0_2:
 	case PSCI_VERSION_1_0:
 	case PSCI_VERSION_1_1:
 		/* Supported EL3 PSCI version. */
 		dlog("Found PSCI version: %#x\n", el3_psci_version);
 		break;

 	default:
 		/* Unsupported EL3 PSCI version. Log a warning but continue. */
 		dlog("Warning: unknown PSCI version: %#x\n", el3_psci_version);
 		el3_psci_version = 0;
 		break;
 	}
 }

 /**
  * Handles PSCI requests received via HVC or SMC instructions from the primary
  * VM.
  *
  * A minimal PSCI 1.1 interface is offered which can make use of the
  * implementation of PSCI in EL3 by acting as an adapter.
  *
  * Returns true if the request was a PSCI one, false otherwise.
  */
 bool psci_primary_vm_handler(struct vcpu *vcpu, uint32_t func, uintreg_t arg0,
 			     uintreg_t arg1, uintreg_t arg2, uintreg_t *ret)
 {
 	struct cpu *c;
 	smc_res_t smc_res;

 	/*
 	 * If there's a problem with the EL3 PSCI, block standard secure service
 	 * calls by marking them as unknown. Other calls will be allowed to pass
 	 * through.
 	 *
 	 * This blocks more calls than just PSCI so it may need to be made more
 	 * lenient in future.
 	 */
 	if (el3_psci_version == 0) {
 		*ret = SMCCC_ERROR_UNKNOWN;
 		return (func & SMCCC_SERVICE_CALL_MASK) ==
 		       SMCCC_STANDARD_SECURE_SERVICE_CALL;
 	}

 	switch (func & ~SMCCC_CONVENTION_MASK) {
 	case PSCI_VERSION:
 		*ret = PSCI_VERSION_1_1;
 		break;

 	case PSCI_FEATURES:
 		switch (arg0 & ~SMCCC_CONVENTION_MASK) {
 		case PSCI_CPU_SUSPEND:
 			if (el3_psci_version == PSCI_VERSION_0_2) {
 				/*
 				 * PSCI 0.2 doesn't support PSCI_FEATURES so
 				 * report PSCI 0.2 compatible features.
 				 */
 				*ret = 0;
 			} else {
 				/* PSCI 1.x only defines two feature bits. */
 				smc_res = smc32(func, arg0, 0, 0, 0, 0, 0,
 						SMCCC_CALLER_HYPERVISOR);
 				*ret = smc_res.res0 & 0x3;
 			}
 			break;

 		case PSCI_VERSION:
 		case PSCI_FEATURES:
 		case PSCI_SYSTEM_OFF:
 		case PSCI_SYSTEM_RESET:
 		case PSCI_AFFINITY_INFO:
 		case PSCI_CPU_OFF:
 		case PSCI_CPU_ON:
 			/* These are supported without special features. */
 			*ret = 0;
 			break;

 		default:
 			/* Everything else is unsupported. */
 			*ret = PSCI_ERROR_NOT_SUPPORTED;
 			break;
 		}
 		break;

 	case PSCI_SYSTEM_OFF:
 		smc32(PSCI_SYSTEM_OFF, 0, 0, 0, 0, 0, 0,
 		      SMCCC_CALLER_HYPERVISOR);
 		panic("System off failed");
 		break;

 	case PSCI_SYSTEM_RESET:
 		smc32(PSCI_SYSTEM_RESET, 0, 0, 0, 0, 0, 0,
 		      SMCCC_CALLER_HYPERVISOR);
 		panic("System reset failed");
 		break;

 	case PSCI_AFFINITY_INFO:
 		c = cpu_find(arg0);
 		if (!c) {
 			*ret = PSCI_ERROR_INVALID_PARAMETERS;
 			break;
 		}

 		if (arg1 != 0) {
 			*ret = PSCI_ERROR_NOT_SUPPORTED;
 			break;
 		}

 		sl_lock(&c->lock);
 		if (c->is_on) {
 			*ret = PSCI_RETURN_ON;
 		} else {
 			*ret = PSCI_RETURN_OFF;
 		}
 		sl_unlock(&c->lock);
 		break;

 	case PSCI_CPU_SUSPEND: {
 		/*
 		 * Update vcpu state to wake from the provided entry point but
 		 * if suspend returns, for example because it failed or was a
 		 * standby power state, the SMC will return and the updated
 		 * vcpu registers will be ignored.
 		 */
 		arch_regs_set_pc_arg(&vcpu->regs, ipa_init(arg1), arg2);
 		smc_res = smc64(PSCI_CPU_SUSPEND, arg0, (uintreg_t)&cpu_entry,
 				(uintreg_t)vcpu->cpu, 0, 0, 0,
 				SMCCC_CALLER_HYPERVISOR);
 		*ret = smc_res.res0;
 		break;
 	}

 	case PSCI_CPU_OFF:
 		cpu_off(vcpu->cpu);
 		smc32(PSCI_CPU_OFF, 0, 0, 0, 0, 0, 0, SMCCC_CALLER_HYPERVISOR);
 		panic("CPU off failed");
 		break;

 	case PSCI_CPU_ON:
 		c = cpu_find(arg0);
 		if (!c) {
 			*ret = PSCI_ERROR_INVALID_PARAMETERS;
 			break;
 		}

 		if (cpu_on(c, ipa_init(arg1), arg2)) {
 			*ret = PSCI_ERROR_ALREADY_ON;
 			break;
 		}

 		/*
 		 * There's a race when turning a CPU on when it's in the
 		 * process of turning off. We need to loop here while it is
 		 * reported that the CPU is on (because it's about to turn
 		 * itself off).
 		 */
 		do {
 			smc_res = smc64(PSCI_CPU_ON, arg0,
 					(uintreg_t)&cpu_entry, (uintreg_t)c, 0,
 					0, 0, SMCCC_CALLER_HYPERVISOR);
 			*ret = smc_res.res0;
 		} while (*ret == PSCI_ERROR_ALREADY_ON);

 		if (*ret != PSCI_RETURN_SUCCESS) {
 			cpu_off(c);
 		}
 		break;

 	case PSCI_MIGRATE:
 	case PSCI_MIGRATE_INFO_TYPE:
 	case PSCI_MIGRATE_INFO_UP_CPU:
 	case PSCI_CPU_FREEZE:
 	case PSCI_CPU_DEFAULT_SUSPEND:
 	case PSCI_NODE_HW_STATE:
 	case PSCI_SYSTEM_SUSPEND:
 	case PSCI_SET_SYSPEND_MODE:
 	case PSCI_STAT_RESIDENCY:
 	case PSCI_STAT_COUNT:
 	case PSCI_SYSTEM_RESET2:
 	case PSCI_MEM_PROTECT:
 	case PSCI_MEM_PROTECT_CHECK_RANGE:
 		/* Block all other known PSCI calls. */
 		*ret = PSCI_ERROR_NOT_SUPPORTED;
 		break;

 	default:
 		return false;
 	}

 	return true;
 }

 /**
  * Convert a PSCI CPU / affinity ID for a secondary VM to the corresponding vCPU
  * index.
  */
 spci_vcpu_index_t vcpu_id_to_index(cpu_id_t vcpu_id)
 {
 	/* For now we use indices as IDs for the purposes of PSCI. */
 	return vcpu_id;
 }

 /**
  * Handles PSCI requests received via HVC or SMC instructions from a secondary
  * VM.
  *
  * A minimal PSCI 1.1 interface is offered which can start and stop vCPUs in
  * collaboration with the scheduler in the primary VM.
  *
  * Returns true if the request was a PSCI one, false otherwise.
  */
 bool psci_secondary_vm_handler(struct vcpu *vcpu, uint32_t func, uintreg_t arg0,
 			       uintreg_t arg1, uintreg_t arg2, uintreg_t *ret,
 			       struct vcpu **next)
 {
 	switch (func & ~SMCCC_CONVENTION_MASK) {
 	case PSCI_VERSION:
 		*ret = PSCI_VERSION_1_1;
 		break;

 	case PSCI_FEATURES:
 		switch (arg0 & ~SMCCC_CONVENTION_MASK) {
 		case PSCI_CPU_SUSPEND:
 			/*
 			 * Does not offer OS-initiated mode but does use
 			 * extended StateID Format.
 			 */
 			*ret = 0x2;
 			break;

 		case PSCI_VERSION:
 		case PSCI_FEATURES:
 		case PSCI_AFFINITY_INFO:
 		case PSCI_CPU_OFF:
 		case PSCI_CPU_ON:
 			/* These are supported without special features. */
 			*ret = 0;
 			break;

 		default:
 			/* Everything else is unsupported. */
 			*ret = PSCI_ERROR_NOT_SUPPORTED;
 			break;
 		}
 		break;

 	case PSCI_AFFINITY_INFO: {
 		cpu_id_t target_affinity = arg0;
 		uint32_t lowest_affinity_level = arg1;
 		struct vm *vm = vcpu->vm;
 		struct vcpu_locked target_vcpu;
 		spci_vcpu_index_t target_vcpu_index =
 			vcpu_id_to_index(target_affinity);

 		if (lowest_affinity_level != 0) {
 			/* Affinity levels greater than 0 not supported. */
 			*ret = PSCI_ERROR_INVALID_PARAMETERS;
 			break;
 		}

 		if (target_vcpu_index >= vm->vcpu_count) {
 			*ret = PSCI_ERROR_INVALID_PARAMETERS;
 			break;
 		}

 		target_vcpu = vcpu_lock(vm_get_vcpu(vm, target_vcpu_index));
 		*ret = vcpu_is_off(target_vcpu) ? PSCI_RETURN_OFF
 						: PSCI_RETURN_ON;
 		vcpu_unlock(&target_vcpu);
 		break;
 	}

 	case PSCI_CPU_SUSPEND: {
 		/*
 		 * Downgrade suspend request to WFI and return SUCCESS, as
 		 * allowed by the specification.
 		 */
 		*next = api_wait_for_interrupt(vcpu);
 		*ret = PSCI_RETURN_SUCCESS;
 		break;
 	}

 	case PSCI_CPU_OFF:
 		/*
 		 * Should never return to the caller, but in case it somehow
 		 * does.
 		 */
 		*ret = PSCI_ERROR_DENIED;
 		/* Tell the scheduler not to run the vCPU again. */
 		*next = api_vcpu_off(vcpu);
 		break;

 	case PSCI_CPU_ON: {
 		/* Parameter names as per PSCI specification. */
 		cpu_id_t target_cpu = arg0;
 		ipaddr_t entry_point_address = ipa_init(arg1);
 		uint64_t context_id = arg2;
 		spci_vcpu_index_t target_vcpu_index =
 			vcpu_id_to_index(target_cpu);
 		struct vm *vm = vcpu->vm;
 		struct vcpu *target_vcpu;

 		if (target_vcpu_index >= vm->vcpu_count) {
 			*ret = PSCI_ERROR_INVALID_PARAMETERS;
 			break;
 		}

 		target_vcpu = vm_get_vcpu(vm, target_vcpu_index);

 		if (vcpu_secondary_reset_and_start(
 			    target_vcpu, entry_point_address, context_id)) {
 			/*
 			 * Tell the scheduler that it can start running the new
 			 * vCPU now.
 			 */
 			*next = api_wake_up(vcpu, target_vcpu);
 			*ret = PSCI_RETURN_SUCCESS;
 		} else {
 			*ret = PSCI_ERROR_ALREADY_ON;
 		}

 		break;
 	}

 	case PSCI_SYSTEM_OFF:
 	case PSCI_SYSTEM_RESET:
 	case PSCI_MIGRATE:
 	case PSCI_MIGRATE_INFO_TYPE:
 	case PSCI_MIGRATE_INFO_UP_CPU:
 	case PSCI_CPU_FREEZE:
 	case PSCI_CPU_DEFAULT_SUSPEND:
 	case PSCI_NODE_HW_STATE:
 	case PSCI_SYSTEM_SUSPEND:
 	case PSCI_SET_SYSPEND_MODE:
 	case PSCI_STAT_RESIDENCY:
 	case PSCI_STAT_COUNT:
 	case PSCI_SYSTEM_RESET2:
 	case PSCI_MEM_PROTECT:
 	case PSCI_MEM_PROTECT_CHECK_RANGE:
 		/* Block all other known PSCI calls. */
 		*ret = PSCI_ERROR_NOT_SUPPORTED;
 		break;

 	default:
 		return false;
 	}

 	return true;
 }

 /**
  * Handles PSCI requests received via HVC or SMC instructions from a VM.
  * Requests from primary and secondary VMs are dealt with differently.
  *
  * Returns true if the request was a PSCI one, false otherwise.
  */
 bool psci_handler(struct vcpu *vcpu, uint32_t func, uintreg_t arg0,
 		  uintreg_t arg1, uintreg_t arg2, uintreg_t *ret,
 		  struct vcpu **next)
 {
 	if (vcpu->vm->id == HF_PRIMARY_VM_ID) {
 		return psci_primary_vm_handler(vcpu, func, arg0, arg1, arg2,
 					       ret);
 	}
 	return psci_secondary_vm_handler(vcpu, func, arg0, arg1, arg2, ret,
 					 next);
 }
	/*
	* Copyright 2019 The Hafnium Authors.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* https://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "psci_handler.h"

	#include <stdint.h>

	#include "hf/arch/types.h"

	#include "hf/api.h"
	#include "hf/cpu.h"
	#include "hf/dlog.h"
	#include "hf/panic.h"
	#include "hf/spci.h"
	#include "hf/vm.h"

	#include "psci.h"
	#include "smc.h"

	static uint32_t el3_psci_version;

	void cpu_entry(struct cpu *c);

	/* Performs arch specific boot time initialisation. */
	void arch_one_time_init(void)
	{
	smc_res_t smc_res =
	smc32(PSCI_VERSION, 0, 0, 0, 0, 0, 0, SMCCC_CALLER_HYPERVISOR);

	el3_psci_version = smc_res.res0;

	/* Check there's nothing unexpected about PSCI. */
	switch (el3_psci_version) {
	case PSCI_VERSION_0_2:
	case PSCI_VERSION_1_0:
	case PSCI_VERSION_1_1:
	/* Supported EL3 PSCI version. */
	dlog("Found PSCI version: %#x\n", el3_psci_version);
	break;

	default:
	/* Unsupported EL3 PSCI version. Log a warning but continue. */
	dlog("Warning: unknown PSCI version: %#x\n", el3_psci_version);
	el3_psci_version = 0;
	break;
	}
	}

	/**
	* Handles PSCI requests received via HVC or SMC instructions from the primary
	* VM.
	*
	* A minimal PSCI 1.1 interface is offered which can make use of the
	* implementation of PSCI in EL3 by acting as an adapter.
	*
	* Returns true if the request was a PSCI one, false otherwise.
	*/
	bool psci_primary_vm_handler(struct vcpu *vcpu, uint32_t func, uintreg_t arg0,
	uintreg_t arg1, uintreg_t arg2, uintreg_t *ret)
	{
	struct cpu *c;
	smc_res_t smc_res;

	/*
	* If there's a problem with the EL3 PSCI, block standard secure service
	* calls by marking them as unknown. Other calls will be allowed to pass
	* through.
	*
	* This blocks more calls than just PSCI so it may need to be made more
	* lenient in future.
	*/
	if (el3_psci_version == 0) {
	*ret = SMCCC_ERROR_UNKNOWN;
	return (func & SMCCC_SERVICE_CALL_MASK) ==
	SMCCC_STANDARD_SECURE_SERVICE_CALL;
	}

	switch (func & ~SMCCC_CONVENTION_MASK) {
	case PSCI_VERSION:
	*ret = PSCI_VERSION_1_1;
	break;

	case PSCI_FEATURES:
	switch (arg0 & ~SMCCC_CONVENTION_MASK) {
	case PSCI_CPU_SUSPEND:
	if (el3_psci_version == PSCI_VERSION_0_2) {
	/*
	* PSCI 0.2 doesn't support PSCI_FEATURES so
	* report PSCI 0.2 compatible features.
	*/
	*ret = 0;
	} else {
	/* PSCI 1.x only defines two feature bits. */
	smc_res = smc32(func, arg0, 0, 0, 0, 0, 0,
	SMCCC_CALLER_HYPERVISOR);
	*ret = smc_res.res0 & 0x3;
	}
	break;

	case PSCI_VERSION:
	case PSCI_FEATURES:
	case PSCI_SYSTEM_OFF:
	case PSCI_SYSTEM_RESET:
	case PSCI_AFFINITY_INFO:
	case PSCI_CPU_OFF:
	case PSCI_CPU_ON:
	/* These are supported without special features. */
	*ret = 0;
	break;

	default:
	/* Everything else is unsupported. */
	*ret = PSCI_ERROR_NOT_SUPPORTED;
	break;
	}
	break;

	case PSCI_SYSTEM_OFF:
	smc32(PSCI_SYSTEM_OFF, 0, 0, 0, 0, 0, 0,
	SMCCC_CALLER_HYPERVISOR);
	panic("System off failed");
	break;

	case PSCI_SYSTEM_RESET:
	smc32(PSCI_SYSTEM_RESET, 0, 0, 0, 0, 0, 0,
	SMCCC_CALLER_HYPERVISOR);
	panic("System reset failed");
	break;

	case PSCI_AFFINITY_INFO:
	c = cpu_find(arg0);
	if (!c) {
	*ret = PSCI_ERROR_INVALID_PARAMETERS;
	break;
	}

	if (arg1 != 0) {
	*ret = PSCI_ERROR_NOT_SUPPORTED;
	break;
	}

	sl_lock(&c->lock);
	if (c->is_on) {
	*ret = PSCI_RETURN_ON;
	} else {
	*ret = PSCI_RETURN_OFF;
	}
	sl_unlock(&c->lock);
	break;

	case PSCI_CPU_SUSPEND: {
	/*
	* Update vcpu state to wake from the provided entry point but
	* if suspend returns, for example because it failed or was a
	* standby power state, the SMC will return and the updated
	* vcpu registers will be ignored.
	*/
	arch_regs_set_pc_arg(&vcpu->regs, ipa_init(arg1), arg2);
	smc_res = smc64(PSCI_CPU_SUSPEND, arg0, (uintreg_t)&cpu_entry,
	(uintreg_t)vcpu->cpu, 0, 0, 0,
	SMCCC_CALLER_HYPERVISOR);
	*ret = smc_res.res0;
	break;
	}

	case PSCI_CPU_OFF:
	cpu_off(vcpu->cpu);
	smc32(PSCI_CPU_OFF, 0, 0, 0, 0, 0, 0, SMCCC_CALLER_HYPERVISOR);
	panic("CPU off failed");
	break;

	case PSCI_CPU_ON:
	c = cpu_find(arg0);
	if (!c) {
	*ret = PSCI_ERROR_INVALID_PARAMETERS;
	break;
	}

	if (cpu_on(c, ipa_init(arg1), arg2)) {
	*ret = PSCI_ERROR_ALREADY_ON;
	break;
	}

	/*
	* There's a race when turning a CPU on when it's in the
	* process of turning off. We need to loop here while it is
	* reported that the CPU is on (because it's about to turn
	* itself off).
	*/
	do {
	smc_res = smc64(PSCI_CPU_ON, arg0,
	(uintreg_t)&cpu_entry, (uintreg_t)c, 0,
	0, 0, SMCCC_CALLER_HYPERVISOR);
	*ret = smc_res.res0;
	} while (*ret == PSCI_ERROR_ALREADY_ON);

	if (*ret != PSCI_RETURN_SUCCESS) {
	cpu_off(c);
	}
	break;

	case PSCI_MIGRATE:
	case PSCI_MIGRATE_INFO_TYPE:
	case PSCI_MIGRATE_INFO_UP_CPU:
	case PSCI_CPU_FREEZE:
	case PSCI_CPU_DEFAULT_SUSPEND:
	case PSCI_NODE_HW_STATE:
	case PSCI_SYSTEM_SUSPEND:
	case PSCI_SET_SYSPEND_MODE:
	case PSCI_STAT_RESIDENCY:
	case PSCI_STAT_COUNT:
	case PSCI_SYSTEM_RESET2:
	case PSCI_MEM_PROTECT:
	case PSCI_MEM_PROTECT_CHECK_RANGE:
	/* Block all other known PSCI calls. */
	*ret = PSCI_ERROR_NOT_SUPPORTED;
	break;

	default:
	return false;
	}

	return true;
	}

	/**
	* Convert a PSCI CPU / affinity ID for a secondary VM to the corresponding vCPU
	* index.
	*/
	spci_vcpu_index_t vcpu_id_to_index(cpu_id_t vcpu_id)
	{
	/* For now we use indices as IDs for the purposes of PSCI. */
	return vcpu_id;
	}

	/**
	* Handles PSCI requests received via HVC or SMC instructions from a secondary
	* VM.
	*
	* A minimal PSCI 1.1 interface is offered which can start and stop vCPUs in
	* collaboration with the scheduler in the primary VM.
	*
	* Returns true if the request was a PSCI one, false otherwise.
	*/
	bool psci_secondary_vm_handler(struct vcpu *vcpu, uint32_t func, uintreg_t arg0,
	uintreg_t arg1, uintreg_t arg2, uintreg_t *ret,
	struct vcpu **next)
	{
	switch (func & ~SMCCC_CONVENTION_MASK) {
	case PSCI_VERSION:
	*ret = PSCI_VERSION_1_1;
	break;

	case PSCI_FEATURES:
	switch (arg0 & ~SMCCC_CONVENTION_MASK) {
	case PSCI_CPU_SUSPEND:
	/*
	* Does not offer OS-initiated mode but does use
	* extended StateID Format.
	*/
	*ret = 0x2;
	break;

	case PSCI_VERSION:
	case PSCI_FEATURES:
	case PSCI_AFFINITY_INFO:
	case PSCI_CPU_OFF:
	case PSCI_CPU_ON:
	/* These are supported without special features. */
	*ret = 0;
	break;

	default:
	/* Everything else is unsupported. */
	*ret = PSCI_ERROR_NOT_SUPPORTED;
	break;
	}
	break;

	case PSCI_AFFINITY_INFO: {
	cpu_id_t target_affinity = arg0;
	uint32_t lowest_affinity_level = arg1;
	struct vm *vm = vcpu->vm;
	struct vcpu_locked target_vcpu;
	spci_vcpu_index_t target_vcpu_index =
	vcpu_id_to_index(target_affinity);

	if (lowest_affinity_level != 0) {
	/* Affinity levels greater than 0 not supported. */
	*ret = PSCI_ERROR_INVALID_PARAMETERS;
	break;
	}

	if (target_vcpu_index >= vm->vcpu_count) {
	*ret = PSCI_ERROR_INVALID_PARAMETERS;
	break;
	}

	target_vcpu = vcpu_lock(vm_get_vcpu(vm, target_vcpu_index));
	*ret = vcpu_is_off(target_vcpu) ? PSCI_RETURN_OFF
	: PSCI_RETURN_ON;
	vcpu_unlock(&target_vcpu);
	break;
	}

	case PSCI_CPU_SUSPEND: {
	/*
	* Downgrade suspend request to WFI and return SUCCESS, as
	* allowed by the specification.
	*/
	*next = api_wait_for_interrupt(vcpu);
	*ret = PSCI_RETURN_SUCCESS;
	break;
	}

	case PSCI_CPU_OFF:
	/*
	* Should never return to the caller, but in case it somehow
	* does.
	*/
	*ret = PSCI_ERROR_DENIED;
	/* Tell the scheduler not to run the vCPU again. */
	*next = api_vcpu_off(vcpu);
	break;

	case PSCI_CPU_ON: {
	/* Parameter names as per PSCI specification. */
	cpu_id_t target_cpu = arg0;
	ipaddr_t entry_point_address = ipa_init(arg1);
	uint64_t context_id = arg2;
	spci_vcpu_index_t target_vcpu_index =
	vcpu_id_to_index(target_cpu);
	struct vm *vm = vcpu->vm;
	struct vcpu *target_vcpu;

	if (target_vcpu_index >= vm->vcpu_count) {
	*ret = PSCI_ERROR_INVALID_PARAMETERS;
	break;
	}

	target_vcpu = vm_get_vcpu(vm, target_vcpu_index);

	if (vcpu_secondary_reset_and_start(
	target_vcpu, entry_point_address, context_id)) {
	/*
	* Tell the scheduler that it can start running the new
	* vCPU now.
	*/
	*next = api_wake_up(vcpu, target_vcpu);
	*ret = PSCI_RETURN_SUCCESS;
	} else {
	*ret = PSCI_ERROR_ALREADY_ON;
	}

	break;
	}

	case PSCI_SYSTEM_OFF:
	case PSCI_SYSTEM_RESET:
	case PSCI_MIGRATE:
	case PSCI_MIGRATE_INFO_TYPE:
	case PSCI_MIGRATE_INFO_UP_CPU:
	case PSCI_CPU_FREEZE:
	case PSCI_CPU_DEFAULT_SUSPEND:
	case PSCI_NODE_HW_STATE:
	case PSCI_SYSTEM_SUSPEND:
	case PSCI_SET_SYSPEND_MODE:
	case PSCI_STAT_RESIDENCY:
	case PSCI_STAT_COUNT:
	case PSCI_SYSTEM_RESET2:
	case PSCI_MEM_PROTECT:
	case PSCI_MEM_PROTECT_CHECK_RANGE:
	/* Block all other known PSCI calls. */
	*ret = PSCI_ERROR_NOT_SUPPORTED;
	break;

	default:
	return false;
	}

	return true;
	}

	/**
	* Handles PSCI requests received via HVC or SMC instructions from a VM.
	* Requests from primary and secondary VMs are dealt with differently.
	*
	* Returns true if the request was a PSCI one, false otherwise.
	*/
	bool psci_handler(struct vcpu *vcpu, uint32_t func, uintreg_t arg0,
	uintreg_t arg1, uintreg_t arg2, uintreg_t *ret,
	struct vcpu **next)
	{
	if (vcpu->vm->id == HF_PRIMARY_VM_ID) {
	return psci_primary_vm_handler(vcpu, func, arg0, arg1, arg2,
	ret);
	}
	return psci_secondary_vm_handler(vcpu, func, arg0, arg1, arg2, ret,
	next);
	}