/* * 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/preempt.h> #include <linux/kvm_host.h> #include <linux/wait.h> #include <asm/cputype.h> #include <asm/kvm_emulate.h> #include <asm/kvm_psci.h> #include <asm/kvm_host.h> #include <uapi/linux/psci.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_block(vcpu); return PSCI_RET_SUCCESS; } static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu) { vcpu->arch.power_off = true; } static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) { struct kvm *kvm = source_vcpu->kvm; struct kvm_vcpu *vcpu = NULL; struct swait_queue_head *wq; unsigned long cpu_id; unsigned long context_id; phys_addr_t target_pc; cpu_id = vcpu_get_reg(source_vcpu, 1) & MPIDR_HWID_BITMASK; if (vcpu_mode_is_32bit(source_vcpu)) cpu_id &= ~((u32) 0); 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; if (!vcpu->arch.power_off) { if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1) return PSCI_RET_ALREADY_ON; else return PSCI_RET_INVALID_PARAMS; } target_pc = vcpu_get_reg(source_vcpu, 2); context_id = vcpu_get_reg(source_vcpu, 3); 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; /* * NOTE: We always update r0 (or x0) because for PSCI v0.1 * the general puspose registers are undefined upon CPU_ON. */ vcpu_set_reg(vcpu, 0, context_id); vcpu->arch.power_off = false; smp_mb(); /* Make sure the above is visible */ wq = kvm_arch_vcpu_wq(vcpu); swake_up(wq); return PSCI_RET_SUCCESS; } static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu) { int i, matching_cpus = 0; unsigned long 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 = vcpu_get_reg(vcpu, 1); lowest_affinity_level = vcpu_get_reg(vcpu, 2); /* 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 (!tmp->arch.power_off) 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) { int 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) { tmp->arch.power_off = true; kvm_vcpu_kick(tmp); } memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event)); vcpu->run->system_event.type = type; 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); } static void kvm_psci_system_reset(struct kvm_vcpu *vcpu) { kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET); } int kvm_psci_version(struct kvm_vcpu *vcpu) { if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features)) return KVM_ARM_PSCI_0_2; return KVM_ARM_PSCI_0_1; } static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) { int ret = 1; unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0); unsigned long val; switch (psci_fn) { case PSCI_0_2_FN_PSCI_VERSION: /* * Bits[31:16] = Major Version = 0 * Bits[15:0] = Minor Version = 2 */ val = 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_psci_vcpu_off(vcpu); val = PSCI_RET_SUCCESS; break; case PSCI_0_2_FN_CPU_ON: case PSCI_0_2_FN64_CPU_ON: val = kvm_psci_vcpu_on(vcpu); break; case PSCI_0_2_FN_AFFINITY_INFO: 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 should'nt be going back to guest VCPU after * receiving SYSTEM_OFF request. * * If user space accidently/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; } vcpu_set_reg(vcpu, 0, val); return ret; } static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) { unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0); unsigned long val; switch (psci_fn) { case KVM_PSCI_FN_CPU_OFF: kvm_psci_vcpu_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; } vcpu_set_reg(vcpu, 0, val); 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) { switch (kvm_psci_version(vcpu)) { 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: return -EINVAL; }; }