LXR linux/arch/arm/kvm/psci.c

   1/*
   2 * Copyright (C) 2012 - ARM Ltd
   3 * Author: Marc Zyngier <marc.zyngier@arm.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18#include <linux/kvm_host.h>
  19#include <linux/wait.h>
  20
  21#include <asm/cputype.h>
  22#include <asm/kvm_emulate.h>
  23#include <asm/kvm_psci.h>
  24
  25/*
  26 * This is an implementation of the Power State Coordination Interface
  27 * as described in ARM document number ARM DEN 0022A.
  28 */
  29
  30static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
  31{
  32        vcpu->arch.pause = true;
  33}
  34
  35static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
  36{
  37        struct kvm *kvm = source_vcpu->kvm;
  38        struct kvm_vcpu *vcpu = NULL, *tmp;
  39        wait_queue_head_t *wq;
  40        unsigned long cpu_id;
  41        unsigned long mpidr;
  42        phys_addr_t target_pc;
  43        int i;
  44
  45        cpu_id = *vcpu_reg(source_vcpu, 1);
  46        if (vcpu_mode_is_32bit(source_vcpu))
  47                cpu_id &= ~((u32) 0);
  48
  49        kvm_for_each_vcpu(i, tmp, kvm) {
  50                mpidr = kvm_vcpu_get_mpidr(tmp);
  51                if ((mpidr & MPIDR_HWID_BITMASK) == (cpu_id & MPIDR_HWID_BITMASK)) {
  52                        vcpu = tmp;
  53                        break;
  54                }
  55        }
  56
  57        /*
  58         * Make sure the caller requested a valid CPU and that the CPU is
  59         * turned off.
  60         */
  61        if (!vcpu || !vcpu->arch.pause)
  62                return KVM_PSCI_RET_INVAL;
  63
  64        target_pc = *vcpu_reg(source_vcpu, 2);
  65
  66        kvm_reset_vcpu(vcpu);
  67
  68        /* Gracefully handle Thumb2 entry point */
  69        if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
  70                target_pc &= ~((phys_addr_t) 1);
  71                vcpu_set_thumb(vcpu);
  72        }
  73
  74        /* Propagate caller endianness */
  75        if (kvm_vcpu_is_be(source_vcpu))
  76                kvm_vcpu_set_be(vcpu);
  77
  78        *vcpu_pc(vcpu) = target_pc;
  79        vcpu->arch.pause = false;
  80        smp_mb();               /* Make sure the above is visible */
  81
  82        wq = kvm_arch_vcpu_wq(vcpu);
  83        wake_up_interruptible(wq);
  84
  85        return KVM_PSCI_RET_SUCCESS;
  86}
  87
  88/**
  89 * kvm_psci_call - handle PSCI call if r0 value is in range
  90 * @vcpu: Pointer to the VCPU struct
  91 *
  92 * Handle PSCI calls from guests through traps from HVC instructions.
  93 * The calling convention is similar to SMC calls to the secure world where
  94 * the function number is placed in r0 and this function returns true if the
  95 * function number specified in r0 is withing the PSCI range, and false
  96 * otherwise.
  97 */
  98bool kvm_psci_call(struct kvm_vcpu *vcpu)
  99{
 100        unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0);
 101        unsigned long val;
 102
 103        switch (psci_fn) {
 104        case KVM_PSCI_FN_CPU_OFF:
 105                kvm_psci_vcpu_off(vcpu);
 106                val = KVM_PSCI_RET_SUCCESS;
 107                break;
 108        case KVM_PSCI_FN_CPU_ON:
 109                val = kvm_psci_vcpu_on(vcpu);
 110                break;
 111        case KVM_PSCI_FN_CPU_SUSPEND:
 112        case KVM_PSCI_FN_MIGRATE:
 113                val = KVM_PSCI_RET_NI;
 114                break;
 115
 116        default:
 117                return false;
 118        }
 119
 120        *vcpu_reg(vcpu, 0) = val;
 121        return true;
 122}
 123