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}