| Marc Zyngier | aa024c2 | 2013-01-20 18:28:13 -0500 | [diff] [blame] | 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/kvm_emulate.h> |
| 22 | #include <asm/kvm_psci.h> |
| 23 | |
| 24 | /* |
| 25 | * This is an implementation of the Power State Coordination Interface |
| 26 | * as described in ARM document number ARM DEN 0022A. |
| 27 | */ |
| 28 | |
| 29 | static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu) |
| 30 | { |
| 31 | vcpu->arch.pause = true; |
| 32 | } |
| 33 | |
| 34 | static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) |
| 35 | { |
| 36 | struct kvm *kvm = source_vcpu->kvm; |
| 37 | struct kvm_vcpu *vcpu; |
| 38 | wait_queue_head_t *wq; |
| 39 | unsigned long cpu_id; |
| 40 | phys_addr_t target_pc; |
| 41 | |
| 42 | cpu_id = *vcpu_reg(source_vcpu, 1); |
| 43 | if (vcpu_mode_is_32bit(source_vcpu)) |
| 44 | cpu_id &= ~((u32) 0); |
| 45 | |
| 46 | if (cpu_id >= atomic_read(&kvm->online_vcpus)) |
| 47 | return KVM_PSCI_RET_INVAL; |
| 48 | |
| 49 | target_pc = *vcpu_reg(source_vcpu, 2); |
| 50 | |
| 51 | vcpu = kvm_get_vcpu(kvm, cpu_id); |
| 52 | |
| 53 | wq = kvm_arch_vcpu_wq(vcpu); |
| 54 | if (!waitqueue_active(wq)) |
| 55 | return KVM_PSCI_RET_INVAL; |
| 56 | |
| 57 | kvm_reset_vcpu(vcpu); |
| 58 | |
| 59 | /* Gracefully handle Thumb2 entry point */ |
| 60 | if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) { |
| 61 | target_pc &= ~((phys_addr_t) 1); |
| 62 | vcpu_set_thumb(vcpu); |
| 63 | } |
| 64 | |
| 65 | *vcpu_pc(vcpu) = target_pc; |
| 66 | vcpu->arch.pause = false; |
| 67 | smp_mb(); /* Make sure the above is visible */ |
| 68 | |
| 69 | wake_up_interruptible(wq); |
| 70 | |
| 71 | return KVM_PSCI_RET_SUCCESS; |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * kvm_psci_call - handle PSCI call if r0 value is in range |
| 76 | * @vcpu: Pointer to the VCPU struct |
| 77 | * |
| 78 | * Handle PSCI calls from guests through traps from HVC or SMC instructions. |
| 79 | * The calling convention is similar to SMC calls to the secure world where |
| 80 | * the function number is placed in r0 and this function returns true if the |
| 81 | * function number specified in r0 is withing the PSCI range, and false |
| 82 | * otherwise. |
| 83 | */ |
| 84 | bool kvm_psci_call(struct kvm_vcpu *vcpu) |
| 85 | { |
| 86 | unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0); |
| 87 | unsigned long val; |
| 88 | |
| 89 | switch (psci_fn) { |
| 90 | case KVM_PSCI_FN_CPU_OFF: |
| 91 | kvm_psci_vcpu_off(vcpu); |
| 92 | val = KVM_PSCI_RET_SUCCESS; |
| 93 | break; |
| 94 | case KVM_PSCI_FN_CPU_ON: |
| 95 | val = kvm_psci_vcpu_on(vcpu); |
| 96 | break; |
| 97 | case KVM_PSCI_FN_CPU_SUSPEND: |
| 98 | case KVM_PSCI_FN_MIGRATE: |
| 99 | val = KVM_PSCI_RET_NI; |
| 100 | break; |
| 101 | |
| 102 | default: |
| 103 | return false; |
| 104 | } |
| 105 | |
| 106 | *vcpu_reg(vcpu, 0) = val; |
| 107 | return true; |
| 108 | } |