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kernel/linux-imx6_3.14.28/arch/arm/kvm/psci.c 3.03 KB
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  /*
   * Copyright (C) 2012 - ARM Ltd
   * Author: Marc Zyngier <marc.zyngier@arm.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  #include <linux/kvm_host.h>
  #include <linux/wait.h>
  
  #include <asm/cputype.h>
  #include <asm/kvm_emulate.h>
  #include <asm/kvm_psci.h>
  
  /*
   * This is an implementation of the Power State Coordination Interface
   * as described in ARM document number ARM DEN 0022A.
   */
  
  static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
  {
  	vcpu->arch.pause = true;
  }
  
  static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
  {
  	struct kvm *kvm = source_vcpu->kvm;
  	struct kvm_vcpu *vcpu = NULL, *tmp;
  	wait_queue_head_t *wq;
  	unsigned long cpu_id;
  	unsigned long mpidr;
  	phys_addr_t target_pc;
  	int i;
  
  	cpu_id = *vcpu_reg(source_vcpu, 1);
  	if (vcpu_mode_is_32bit(source_vcpu))
  		cpu_id &= ~((u32) 0);
  
  	kvm_for_each_vcpu(i, tmp, kvm) {
  		mpidr = kvm_vcpu_get_mpidr(tmp);
  		if ((mpidr & MPIDR_HWID_BITMASK) == (cpu_id & MPIDR_HWID_BITMASK)) {
  			vcpu = tmp;
  			break;
  		}
  	}
  
  	/*
  	 * Make sure the caller requested a valid CPU and that the CPU is
  	 * turned off.
  	 */
  	if (!vcpu || !vcpu->arch.pause)
  		return KVM_PSCI_RET_INVAL;
  
  	target_pc = *vcpu_reg(source_vcpu, 2);
  
  	kvm_reset_vcpu(vcpu);
  
  	/* Gracefully handle Thumb2 entry point */
  	if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
  		target_pc &= ~((phys_addr_t) 1);
  		vcpu_set_thumb(vcpu);
  	}
  
  	/* Propagate caller endianness */
  	if (kvm_vcpu_is_be(source_vcpu))
  		kvm_vcpu_set_be(vcpu);
  
  	*vcpu_pc(vcpu) = target_pc;
  	vcpu->arch.pause = false;
  	smp_mb();		/* Make sure the above is visible */
  
  	wq = kvm_arch_vcpu_wq(vcpu);
  	wake_up_interruptible(wq);
  
  	return KVM_PSCI_RET_SUCCESS;
  }
  
  /**
   * 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 and this function returns true if the
   * function number specified in r0 is withing the PSCI range, and false
   * otherwise.
   */
  bool kvm_psci_call(struct kvm_vcpu *vcpu)
  {
  	unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
  	unsigned long val;
  
  	switch (psci_fn) {
  	case KVM_PSCI_FN_CPU_OFF:
  		kvm_psci_vcpu_off(vcpu);
  		val = KVM_PSCI_RET_SUCCESS;
  		break;
  	case KVM_PSCI_FN_CPU_ON:
  		val = kvm_psci_vcpu_on(vcpu);
  		break;
  	case KVM_PSCI_FN_CPU_SUSPEND:
  	case KVM_PSCI_FN_MIGRATE:
  		val = KVM_PSCI_RET_NI;
  		break;
  
  	default:
  		return false;
  	}
  
  	*vcpu_reg(vcpu, 0) = val;
  	return true;
  }