arch/arm64/kvm/psci.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012 - ARM Ltd
  * Author: Marc Zyngier <marc.zyngier@arm.com>
  */

 #include <linux/arm-smccc.h>
 #include <linux/preempt.h>
 #include <linux/kvm_host.h>
 #include <linux/uaccess.h>
 #include <linux/wait.h>

 #include <asm/cputype.h>
 #include <asm/kvm_emulate.h>

 #include <kvm/arm_psci.h>
 #include <kvm/arm_hypercalls.h>

 /*
  * This is an implementation of the Power State Coordination Interface
  * as described in ARM document number ARM DEN 0022A.
  */

 #define AFFINITY_MASK(level)	~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)

 static unsigned long psci_affinity_mask(unsigned long affinity_level)
 {
 	if (affinity_level <= 3)
 		return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);

 	return 0;
 }

 static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
 {
 	/*
 	 * NOTE: For simplicity, we make VCPU suspend emulation to be
 	 * same-as WFI (Wait-for-interrupt) emulation.
 	 *
 	 * This means for KVM the wakeup events are interrupts and
 	 * this is consistent with intended use of StateID as described
 	 * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
 	 *
 	 * Further, we also treat power-down request to be same as
 	 * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
 	 * specification (ARM DEN 0022A). This means all suspend states
 	 * for KVM will preserve the register state.
 	 */
 	kvm_vcpu_wfi(vcpu);

 	return PSCI_RET_SUCCESS;
 }

 static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu,
 					   unsigned long affinity)
 {
 	return !(affinity & ~MPIDR_HWID_BITMASK);
 }

 static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
 {
 	struct vcpu_reset_state *reset_state;
 	struct kvm *kvm = source_vcpu->kvm;
 	struct kvm_vcpu *vcpu = NULL;
 	int ret = PSCI_RET_SUCCESS;
 	unsigned long cpu_id;

 	cpu_id = smccc_get_arg1(source_vcpu);
 	if (!kvm_psci_valid_affinity(source_vcpu, cpu_id))
 		return PSCI_RET_INVALID_PARAMS;

 	vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);

 	/*
 	 * Make sure the caller requested a valid CPU and that the CPU is
 	 * turned off.
 	 */
 	if (!vcpu)
 		return PSCI_RET_INVALID_PARAMS;

 	spin_lock(&vcpu->arch.mp_state_lock);
 	if (!kvm_arm_vcpu_stopped(vcpu)) {
 		if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
 			ret = PSCI_RET_ALREADY_ON;
 		else
 			ret = PSCI_RET_INVALID_PARAMS;

 		goto out_unlock;
 	}

 	reset_state = &vcpu->arch.reset_state;

 	reset_state->pc = smccc_get_arg2(source_vcpu);

 	/* Propagate caller endianness */
 	reset_state->be = kvm_vcpu_is_be(source_vcpu);

 	/*
 	 * NOTE: We always update r0 (or x0) because for PSCI v0.1
 	 * the general purpose registers are undefined upon CPU_ON.
 	 */
 	reset_state->r0 = smccc_get_arg3(source_vcpu);

 	reset_state->reset = true;
 	kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);

 	/*
 	 * Make sure the reset request is observed if the RUNNABLE mp_state is
 	 * observed.
 	 */
 	smp_wmb();

 	WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE);
 	kvm_vcpu_wake_up(vcpu);

 out_unlock:
 	spin_unlock(&vcpu->arch.mp_state_lock);
 	return ret;
 }

 static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
 {
 	int matching_cpus = 0;
 	unsigned long i, mpidr;
 	unsigned long target_affinity;
 	unsigned long target_affinity_mask;
 	unsigned long lowest_affinity_level;
 	struct kvm *kvm = vcpu->kvm;
 	struct kvm_vcpu *tmp;

 	target_affinity = smccc_get_arg1(vcpu);
 	lowest_affinity_level = smccc_get_arg2(vcpu);

 	if (!kvm_psci_valid_affinity(vcpu, target_affinity))
 		return PSCI_RET_INVALID_PARAMS;

 	/* Determine target affinity mask */
 	target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
 	if (!target_affinity_mask)
 		return PSCI_RET_INVALID_PARAMS;

 	/* Ignore other bits of target affinity */
 	target_affinity &= target_affinity_mask;

 	/*
 	 * If one or more VCPU matching target affinity are running
 	 * then ON else OFF
 	 */
 	kvm_for_each_vcpu(i, tmp, kvm) {
 		mpidr = kvm_vcpu_get_mpidr_aff(tmp);
 		if ((mpidr & target_affinity_mask) == target_affinity) {
 			matching_cpus++;
 			if (!kvm_arm_vcpu_stopped(tmp))
 				return PSCI_0_2_AFFINITY_LEVEL_ON;
 		}
 	}

 	if (!matching_cpus)
 		return PSCI_RET_INVALID_PARAMS;

 	return PSCI_0_2_AFFINITY_LEVEL_OFF;
 }

 static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
 {
 	unsigned long i;
 	struct kvm_vcpu *tmp;

 	/*
 	 * The KVM ABI specifies that a system event exit may call KVM_RUN
 	 * again and may perform shutdown/reboot at a later time that when the
 	 * actual request is made.  Since we are implementing PSCI and a
 	 * caller of PSCI reboot and shutdown expects that the system shuts
 	 * down or reboots immediately, let's make sure that VCPUs are not run
 	 * after this call is handled and before the VCPUs have been
 	 * re-initialized.
 	 */
 	kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
 		spin_lock(&tmp->arch.mp_state_lock);
 		WRITE_ONCE(tmp->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED);
 		spin_unlock(&tmp->arch.mp_state_lock);
 	}
 	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);

 	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
 	vcpu->run->system_event.type = type;
 	vcpu->run->system_event.ndata = 1;
 	vcpu->run->system_event.data[0] = flags;
 	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 }

 static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
 {
 	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, 0);
 }

 static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
 {
 	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET, 0);
 }

 static void kvm_psci_system_reset2(struct kvm_vcpu *vcpu)
 {
 	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET,
 				 KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2);
 }

 static void kvm_psci_system_suspend(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;

 	memset(&run->system_event, 0, sizeof(vcpu->run->system_event));
 	run->system_event.type = KVM_SYSTEM_EVENT_SUSPEND;
 	run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 }

 static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
 {
 	int i;

 	/*
 	 * Zero the input registers' upper 32 bits. They will be fully
 	 * zeroed on exit, so we're fine changing them in place.
 	 */
 	for (i = 1; i < 4; i++)
 		vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i)));
 }

 static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
 {
 	/*
 	 * Prevent 32 bit guests from calling 64 bit PSCI functions.
 	 */
 	if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
 		return PSCI_RET_NOT_SUPPORTED;

 	return 0;
 }

 static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
 {
 	u32 psci_fn = smccc_get_function(vcpu);
 	unsigned long val;
 	int ret = 1;

 	switch (psci_fn) {
 	case PSCI_0_2_FN_PSCI_VERSION:
 		/*
 		 * Bits[31:16] = Major Version = 0
 		 * Bits[15:0] = Minor Version = 2
 		 */
 		val = KVM_ARM_PSCI_0_2;
 		break;
 	case PSCI_0_2_FN_CPU_SUSPEND:
 	case PSCI_0_2_FN64_CPU_SUSPEND:
 		val = kvm_psci_vcpu_suspend(vcpu);
 		break;
 	case PSCI_0_2_FN_CPU_OFF:
 		kvm_arm_vcpu_power_off(vcpu);
 		val = PSCI_RET_SUCCESS;
 		break;
 	case PSCI_0_2_FN_CPU_ON:
 		kvm_psci_narrow_to_32bit(vcpu);
 		fallthrough;
 	case PSCI_0_2_FN64_CPU_ON:
 		val = kvm_psci_vcpu_on(vcpu);
 		break;
 	case PSCI_0_2_FN_AFFINITY_INFO:
 		kvm_psci_narrow_to_32bit(vcpu);
 		fallthrough;
 	case PSCI_0_2_FN64_AFFINITY_INFO:
 		val = kvm_psci_vcpu_affinity_info(vcpu);
 		break;
 	case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
 		/*
 		 * Trusted OS is MP hence does not require migration
 	         * or
 		 * Trusted OS is not present
 		 */
 		val = PSCI_0_2_TOS_MP;
 		break;
 	case PSCI_0_2_FN_SYSTEM_OFF:
 		kvm_psci_system_off(vcpu);
 		/*
 		 * We shouldn't be going back to guest VCPU after
 		 * receiving SYSTEM_OFF request.
 		 *
 		 * If user space accidentally/deliberately resumes
 		 * guest VCPU after SYSTEM_OFF request then guest
 		 * VCPU should see internal failure from PSCI return
 		 * value. To achieve this, we preload r0 (or x0) with
 		 * PSCI return value INTERNAL_FAILURE.
 		 */
 		val = PSCI_RET_INTERNAL_FAILURE;
 		ret = 0;
 		break;
 	case PSCI_0_2_FN_SYSTEM_RESET:
 		kvm_psci_system_reset(vcpu);
 		/*
 		 * Same reason as SYSTEM_OFF for preloading r0 (or x0)
 		 * with PSCI return value INTERNAL_FAILURE.
 		 */
 		val = PSCI_RET_INTERNAL_FAILURE;
 		ret = 0;
 		break;
 	default:
 		val = PSCI_RET_NOT_SUPPORTED;
 		break;
 	}

 	smccc_set_retval(vcpu, val, 0, 0, 0);
 	return ret;
 }

 static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
 {
 	unsigned long val = PSCI_RET_NOT_SUPPORTED;
 	u32 psci_fn = smccc_get_function(vcpu);
 	struct kvm *kvm = vcpu->kvm;
 	u32 arg;
 	int ret = 1;

 	switch(psci_fn) {
 	case PSCI_0_2_FN_PSCI_VERSION:
 		val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
 		break;
 	case PSCI_1_0_FN_PSCI_FEATURES:
 		arg = smccc_get_arg1(vcpu);
 		val = kvm_psci_check_allowed_function(vcpu, arg);
 		if (val)
 			break;

 		val = PSCI_RET_NOT_SUPPORTED;

 		switch(arg) {
 		case PSCI_0_2_FN_PSCI_VERSION:
 		case PSCI_0_2_FN_CPU_SUSPEND:
 		case PSCI_0_2_FN64_CPU_SUSPEND:
 		case PSCI_0_2_FN_CPU_OFF:
 		case PSCI_0_2_FN_CPU_ON:
 		case PSCI_0_2_FN64_CPU_ON:
 		case PSCI_0_2_FN_AFFINITY_INFO:
 		case PSCI_0_2_FN64_AFFINITY_INFO:
 		case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
 		case PSCI_0_2_FN_SYSTEM_OFF:
 		case PSCI_0_2_FN_SYSTEM_RESET:
 		case PSCI_1_0_FN_PSCI_FEATURES:
 		case ARM_SMCCC_VERSION_FUNC_ID:
 			val = 0;
 			break;
 		case PSCI_1_0_FN_SYSTEM_SUSPEND:
 		case PSCI_1_0_FN64_SYSTEM_SUSPEND:
 			if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags))
 				val = 0;
 			break;
 		case PSCI_1_1_FN_SYSTEM_RESET2:
 		case PSCI_1_1_FN64_SYSTEM_RESET2:
 			if (minor >= 1)
 				val = 0;
 			break;
 		}
 		break;
 	case PSCI_1_0_FN_SYSTEM_SUSPEND:
 		kvm_psci_narrow_to_32bit(vcpu);
 		fallthrough;
 	case PSCI_1_0_FN64_SYSTEM_SUSPEND:
 		/*
 		 * Return directly to userspace without changing the vCPU's
 		 * registers. Userspace depends on reading the SMCCC parameters
 		 * to implement SYSTEM_SUSPEND.
 		 */
 		if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags)) {
 			kvm_psci_system_suspend(vcpu);
 			return 0;
 		}
 		break;
 	case PSCI_1_1_FN_SYSTEM_RESET2:
 		kvm_psci_narrow_to_32bit(vcpu);
 		fallthrough;
 	case PSCI_1_1_FN64_SYSTEM_RESET2:
 		if (minor >= 1) {
 			arg = smccc_get_arg1(vcpu);

 			if (arg <= PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET ||
 			    arg >= PSCI_1_1_RESET_TYPE_VENDOR_START) {
 				kvm_psci_system_reset2(vcpu);
 				vcpu_set_reg(vcpu, 0, PSCI_RET_INTERNAL_FAILURE);
 				return 0;
 			}

 			val = PSCI_RET_INVALID_PARAMS;
 			break;
 		}
 		break;
 	default:
 		return kvm_psci_0_2_call(vcpu);
 	}

 	smccc_set_retval(vcpu, val, 0, 0, 0);
 	return ret;
 }

 static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
 {
 	u32 psci_fn = smccc_get_function(vcpu);
 	unsigned long val;

 	switch (psci_fn) {
 	case KVM_PSCI_FN_CPU_OFF:
 		kvm_arm_vcpu_power_off(vcpu);
 		val = PSCI_RET_SUCCESS;
 		break;
 	case KVM_PSCI_FN_CPU_ON:
 		val = kvm_psci_vcpu_on(vcpu);
 		break;
 	default:
 		val = PSCI_RET_NOT_SUPPORTED;
 		break;
 	}

 	smccc_set_retval(vcpu, val, 0, 0, 0);
 	return 1;
 }

 /**
  * kvm_psci_call - handle PSCI call if r0 value is in range
  * @vcpu: Pointer to the VCPU struct
  *
  * Handle PSCI calls from guests through traps from HVC instructions.
  * The calling convention is similar to SMC calls to the secure world
  * where the function number is placed in r0.
  *
  * This function returns: > 0 (success), 0 (success but exit to user
  * space), and < 0 (errors)
  *
  * Errors:
  * -EINVAL: Unrecognized PSCI function
  */
 int kvm_psci_call(struct kvm_vcpu *vcpu)
 {
 	u32 psci_fn = smccc_get_function(vcpu);
 	int version = kvm_psci_version(vcpu);
 	unsigned long val;

 	val = kvm_psci_check_allowed_function(vcpu, psci_fn);
 	if (val) {
 		smccc_set_retval(vcpu, val, 0, 0, 0);
 		return 1;
 	}

 	switch (version) {
 	case KVM_ARM_PSCI_1_1:
 		return kvm_psci_1_x_call(vcpu, 1);
 	case KVM_ARM_PSCI_1_0:
 		return kvm_psci_1_x_call(vcpu, 0);
 	case KVM_ARM_PSCI_0_2:
 		return kvm_psci_0_2_call(vcpu);
 	case KVM_ARM_PSCI_0_1:
 		return kvm_psci_0_1_call(vcpu);
 	default:
 		WARN_ONCE(1, "Unknown PSCI version %d", version);
 		smccc_set_retval(vcpu, SMCCC_RET_NOT_SUPPORTED, 0, 0, 0);
 		return 1;
 	}
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2012 - ARM Ltd
	* Author: Marc Zyngier <marc.zyngier@arm.com>
	*/

	#include <linux/arm-smccc.h>
	#include <linux/preempt.h>
	#include <linux/kvm_host.h>
	#include <linux/uaccess.h>
	#include <linux/wait.h>

	#include <asm/cputype.h>
	#include <asm/kvm_emulate.h>

	#include <kvm/arm_psci.h>
	#include <kvm/arm_hypercalls.h>

	/*
	* This is an implementation of the Power State Coordination Interface
	* as described in ARM document number ARM DEN 0022A.
	*/

	#define AFFINITY_MASK(level) ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)

	static unsigned long psci_affinity_mask(unsigned long affinity_level)
	{
	if (affinity_level <= 3)
	return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);

	return 0;
	}

	static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
	{
	/*
	* NOTE: For simplicity, we make VCPU suspend emulation to be
	* same-as WFI (Wait-for-interrupt) emulation.
	*
	* This means for KVM the wakeup events are interrupts and
	* this is consistent with intended use of StateID as described
	* in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
	*
	* Further, we also treat power-down request to be same as
	* stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
	* specification (ARM DEN 0022A). This means all suspend states
	* for KVM will preserve the register state.
	*/
	kvm_vcpu_wfi(vcpu);

	return PSCI_RET_SUCCESS;
	}

	static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu,
	unsigned long affinity)
	{
	return !(affinity & ~MPIDR_HWID_BITMASK);
	}

	static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
	{
	struct vcpu_reset_state *reset_state;
	struct kvm *kvm = source_vcpu->kvm;
	struct kvm_vcpu *vcpu = NULL;
	int ret = PSCI_RET_SUCCESS;
	unsigned long cpu_id;

	cpu_id = smccc_get_arg1(source_vcpu);
	if (!kvm_psci_valid_affinity(source_vcpu, cpu_id))
	return PSCI_RET_INVALID_PARAMS;

	vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);

	/*
	* Make sure the caller requested a valid CPU and that the CPU is
	* turned off.
	*/
	if (!vcpu)
	return PSCI_RET_INVALID_PARAMS;

	spin_lock(&vcpu->arch.mp_state_lock);
	if (!kvm_arm_vcpu_stopped(vcpu)) {
	if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
	ret = PSCI_RET_ALREADY_ON;
	else
	ret = PSCI_RET_INVALID_PARAMS;

	goto out_unlock;
	}

	reset_state = &vcpu->arch.reset_state;

	reset_state->pc = smccc_get_arg2(source_vcpu);

	/* Propagate caller endianness */
	reset_state->be = kvm_vcpu_is_be(source_vcpu);

	/*
	* NOTE: We always update r0 (or x0) because for PSCI v0.1
	* the general purpose registers are undefined upon CPU_ON.
	*/
	reset_state->r0 = smccc_get_arg3(source_vcpu);

	reset_state->reset = true;
	kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);

	/*
	* Make sure the reset request is observed if the RUNNABLE mp_state is
	* observed.
	*/
	smp_wmb();

	WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE);
	kvm_vcpu_wake_up(vcpu);

	out_unlock:
	spin_unlock(&vcpu->arch.mp_state_lock);
	return ret;
	}

	static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
	{
	int matching_cpus = 0;
	unsigned long i, mpidr;
	unsigned long target_affinity;
	unsigned long target_affinity_mask;
	unsigned long lowest_affinity_level;
	struct kvm *kvm = vcpu->kvm;
	struct kvm_vcpu *tmp;

	target_affinity = smccc_get_arg1(vcpu);
	lowest_affinity_level = smccc_get_arg2(vcpu);

	if (!kvm_psci_valid_affinity(vcpu, target_affinity))
	return PSCI_RET_INVALID_PARAMS;

	/* Determine target affinity mask */
	target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
	if (!target_affinity_mask)
	return PSCI_RET_INVALID_PARAMS;

	/* Ignore other bits of target affinity */
	target_affinity &= target_affinity_mask;

	/*
	* If one or more VCPU matching target affinity are running
	* then ON else OFF
	*/
	kvm_for_each_vcpu(i, tmp, kvm) {
	mpidr = kvm_vcpu_get_mpidr_aff(tmp);
	if ((mpidr & target_affinity_mask) == target_affinity) {
	matching_cpus++;
	if (!kvm_arm_vcpu_stopped(tmp))
	return PSCI_0_2_AFFINITY_LEVEL_ON;
	}
	}

	if (!matching_cpus)
	return PSCI_RET_INVALID_PARAMS;

	return PSCI_0_2_AFFINITY_LEVEL_OFF;
	}

	static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
	{
	unsigned long i;
	struct kvm_vcpu *tmp;

	/*
	* The KVM ABI specifies that a system event exit may call KVM_RUN
	* again and may perform shutdown/reboot at a later time that when the
	* actual request is made. Since we are implementing PSCI and a
	* caller of PSCI reboot and shutdown expects that the system shuts
	* down or reboots immediately, let's make sure that VCPUs are not run
	* after this call is handled and before the VCPUs have been
	* re-initialized.
	*/
	kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
	spin_lock(&tmp->arch.mp_state_lock);
	WRITE_ONCE(tmp->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED);
	spin_unlock(&tmp->arch.mp_state_lock);
	}
	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);

	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
	vcpu->run->system_event.type = type;
	vcpu->run->system_event.ndata = 1;
	vcpu->run->system_event.data[0] = flags;
	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
	}

	static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
	{
	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN, 0);
	}

	static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
	{
	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET, 0);
	}

	static void kvm_psci_system_reset2(struct kvm_vcpu *vcpu)
	{
	kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET,
	KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2);
	}

	static void kvm_psci_system_suspend(struct kvm_vcpu *vcpu)
	{
	struct kvm_run *run = vcpu->run;

	memset(&run->system_event, 0, sizeof(vcpu->run->system_event));
	run->system_event.type = KVM_SYSTEM_EVENT_SUSPEND;
	run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
	}

	static void kvm_psci_narrow_to_32bit(struct kvm_vcpu *vcpu)
	{
	int i;

	/*
	* Zero the input registers' upper 32 bits. They will be fully
	* zeroed on exit, so we're fine changing them in place.
	*/
	for (i = 1; i < 4; i++)
	vcpu_set_reg(vcpu, i, lower_32_bits(vcpu_get_reg(vcpu, i)));
	}

	static unsigned long kvm_psci_check_allowed_function(struct kvm_vcpu *vcpu, u32 fn)
	{
	/*
	* Prevent 32 bit guests from calling 64 bit PSCI functions.
	*/
	if ((fn & PSCI_0_2_64BIT) && vcpu_mode_is_32bit(vcpu))
	return PSCI_RET_NOT_SUPPORTED;

	return 0;
	}

	static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
	{
	u32 psci_fn = smccc_get_function(vcpu);
	unsigned long val;
	int ret = 1;

	switch (psci_fn) {
	case PSCI_0_2_FN_PSCI_VERSION:
	/*
	* Bits[31:16] = Major Version = 0
	* Bits[15:0] = Minor Version = 2
	*/
	val = KVM_ARM_PSCI_0_2;
	break;
	case PSCI_0_2_FN_CPU_SUSPEND:
	case PSCI_0_2_FN64_CPU_SUSPEND:
	val = kvm_psci_vcpu_suspend(vcpu);
	break;
	case PSCI_0_2_FN_CPU_OFF:
	kvm_arm_vcpu_power_off(vcpu);
	val = PSCI_RET_SUCCESS;
	break;
	case PSCI_0_2_FN_CPU_ON:
	kvm_psci_narrow_to_32bit(vcpu);
	fallthrough;
	case PSCI_0_2_FN64_CPU_ON:
	val = kvm_psci_vcpu_on(vcpu);
	break;
	case PSCI_0_2_FN_AFFINITY_INFO:
	kvm_psci_narrow_to_32bit(vcpu);
	fallthrough;
	case PSCI_0_2_FN64_AFFINITY_INFO:
	val = kvm_psci_vcpu_affinity_info(vcpu);
	break;
	case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
	/*
	* Trusted OS is MP hence does not require migration
	* or
	* Trusted OS is not present
	*/
	val = PSCI_0_2_TOS_MP;
	break;
	case PSCI_0_2_FN_SYSTEM_OFF:
	kvm_psci_system_off(vcpu);
	/*
	* We shouldn't be going back to guest VCPU after
	* receiving SYSTEM_OFF request.
	*
	* If user space accidentally/deliberately resumes
	* guest VCPU after SYSTEM_OFF request then guest
	* VCPU should see internal failure from PSCI return
	* value. To achieve this, we preload r0 (or x0) with
	* PSCI return value INTERNAL_FAILURE.
	*/
	val = PSCI_RET_INTERNAL_FAILURE;
	ret = 0;
	break;
	case PSCI_0_2_FN_SYSTEM_RESET:
	kvm_psci_system_reset(vcpu);
	/*
	* Same reason as SYSTEM_OFF for preloading r0 (or x0)
	* with PSCI return value INTERNAL_FAILURE.
	*/
	val = PSCI_RET_INTERNAL_FAILURE;
	ret = 0;
	break;
	default:
	val = PSCI_RET_NOT_SUPPORTED;
	break;
	}

	smccc_set_retval(vcpu, val, 0, 0, 0);
	return ret;
	}

	static int kvm_psci_1_x_call(struct kvm_vcpu *vcpu, u32 minor)
	{
	unsigned long val = PSCI_RET_NOT_SUPPORTED;
	u32 psci_fn = smccc_get_function(vcpu);
	struct kvm *kvm = vcpu->kvm;
	u32 arg;
	int ret = 1;

	switch(psci_fn) {
	case PSCI_0_2_FN_PSCI_VERSION:
	val = minor == 0 ? KVM_ARM_PSCI_1_0 : KVM_ARM_PSCI_1_1;
	break;
	case PSCI_1_0_FN_PSCI_FEATURES:
	arg = smccc_get_arg1(vcpu);
	val = kvm_psci_check_allowed_function(vcpu, arg);
	if (val)
	break;

	val = PSCI_RET_NOT_SUPPORTED;

	switch(arg) {
	case PSCI_0_2_FN_PSCI_VERSION:
	case PSCI_0_2_FN_CPU_SUSPEND:
	case PSCI_0_2_FN64_CPU_SUSPEND:
	case PSCI_0_2_FN_CPU_OFF:
	case PSCI_0_2_FN_CPU_ON:
	case PSCI_0_2_FN64_CPU_ON:
	case PSCI_0_2_FN_AFFINITY_INFO:
	case PSCI_0_2_FN64_AFFINITY_INFO:
	case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
	case PSCI_0_2_FN_SYSTEM_OFF:
	case PSCI_0_2_FN_SYSTEM_RESET:
	case PSCI_1_0_FN_PSCI_FEATURES:
	case ARM_SMCCC_VERSION_FUNC_ID:
	val = 0;
	break;
	case PSCI_1_0_FN_SYSTEM_SUSPEND:
	case PSCI_1_0_FN64_SYSTEM_SUSPEND:
	if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags))
	val = 0;
	break;
	case PSCI_1_1_FN_SYSTEM_RESET2:
	case PSCI_1_1_FN64_SYSTEM_RESET2:
	if (minor >= 1)
	val = 0;
	break;
	}
	break;
	case PSCI_1_0_FN_SYSTEM_SUSPEND:
	kvm_psci_narrow_to_32bit(vcpu);
	fallthrough;
	case PSCI_1_0_FN64_SYSTEM_SUSPEND:
	/*
	* Return directly to userspace without changing the vCPU's
	* registers. Userspace depends on reading the SMCCC parameters
	* to implement SYSTEM_SUSPEND.
	*/
	if (test_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags)) {
	kvm_psci_system_suspend(vcpu);
	return 0;
	}
	break;
	case PSCI_1_1_FN_SYSTEM_RESET2:
	kvm_psci_narrow_to_32bit(vcpu);
	fallthrough;
	case PSCI_1_1_FN64_SYSTEM_RESET2:
	if (minor >= 1) {
	arg = smccc_get_arg1(vcpu);

	if (arg <= PSCI_1_1_RESET_TYPE_SYSTEM_WARM_RESET \|\|
	arg >= PSCI_1_1_RESET_TYPE_VENDOR_START) {
	kvm_psci_system_reset2(vcpu);
	vcpu_set_reg(vcpu, 0, PSCI_RET_INTERNAL_FAILURE);
	return 0;
	}

	val = PSCI_RET_INVALID_PARAMS;
	break;
	}
	break;
	default:
	return kvm_psci_0_2_call(vcpu);
	}

	smccc_set_retval(vcpu, val, 0, 0, 0);
	return ret;
	}

	static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
	{
	u32 psci_fn = smccc_get_function(vcpu);
	unsigned long val;

	switch (psci_fn) {
	case KVM_PSCI_FN_CPU_OFF:
	kvm_arm_vcpu_power_off(vcpu);
	val = PSCI_RET_SUCCESS;
	break;
	case KVM_PSCI_FN_CPU_ON:
	val = kvm_psci_vcpu_on(vcpu);
	break;
	default:
	val = PSCI_RET_NOT_SUPPORTED;
	break;
	}

	smccc_set_retval(vcpu, val, 0, 0, 0);
	return 1;
	}

	/**
	* kvm_psci_call - handle PSCI call if r0 value is in range
	* @vcpu: Pointer to the VCPU struct
	*
	* Handle PSCI calls from guests through traps from HVC instructions.
	* The calling convention is similar to SMC calls to the secure world
	* where the function number is placed in r0.
	*
	* This function returns: > 0 (success), 0 (success but exit to user
	* space), and < 0 (errors)
	*
	* Errors:
	* -EINVAL: Unrecognized PSCI function
	*/
	int kvm_psci_call(struct kvm_vcpu *vcpu)
	{
	u32 psci_fn = smccc_get_function(vcpu);
	int version = kvm_psci_version(vcpu);
	unsigned long val;

	val = kvm_psci_check_allowed_function(vcpu, psci_fn);
	if (val) {
	smccc_set_retval(vcpu, val, 0, 0, 0);
	return 1;
	}

	switch (version) {
	case KVM_ARM_PSCI_1_1:
	return kvm_psci_1_x_call(vcpu, 1);
	case KVM_ARM_PSCI_1_0:
	return kvm_psci_1_x_call(vcpu, 0);
	case KVM_ARM_PSCI_0_2:
	return kvm_psci_0_2_call(vcpu);
	case KVM_ARM_PSCI_0_1:
	return kvm_psci_0_1_call(vcpu);
	default:
	WARN_ONCE(1, "Unknown PSCI version %d", version);
	smccc_set_retval(vcpu, SMCCC_RET_NOT_SUPPORTED, 0, 0, 0);
	return 1;
	}
	}