335 lines
8.6 KiB
C
335 lines
8.6 KiB
C
/*
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* Copyright (C) 2012 - ARM Ltd
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/preempt.h>
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#include <linux/kvm_host.h>
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#include <linux/wait.h>
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#include <asm/cputype.h>
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#include <asm/kvm_emulate.h>
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#include <asm/kvm_psci.h>
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#include <asm/kvm_host.h>
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#include <uapi/linux/psci.h>
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/*
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* This is an implementation of the Power State Coordination Interface
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* as described in ARM document number ARM DEN 0022A.
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*/
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#define AFFINITY_MASK(level) ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
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static unsigned long psci_affinity_mask(unsigned long affinity_level)
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{
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if (affinity_level <= 3)
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return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
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return 0;
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}
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static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
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{
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/*
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* NOTE: For simplicity, we make VCPU suspend emulation to be
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* same-as WFI (Wait-for-interrupt) emulation.
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*
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* This means for KVM the wakeup events are interrupts and
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* this is consistent with intended use of StateID as described
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* in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
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*
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* Further, we also treat power-down request to be same as
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* stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
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* specification (ARM DEN 0022A). This means all suspend states
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* for KVM will preserve the register state.
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*/
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kvm_vcpu_block(vcpu);
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kvm_clear_request(KVM_REQ_UNHALT, vcpu);
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return PSCI_RET_SUCCESS;
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}
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static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
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{
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vcpu->arch.power_off = true;
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kvm_make_request(KVM_REQ_SLEEP, vcpu);
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kvm_vcpu_kick(vcpu);
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}
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static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
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{
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struct kvm *kvm = source_vcpu->kvm;
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struct kvm_vcpu *vcpu = NULL;
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struct swait_queue_head *wq;
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unsigned long cpu_id;
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unsigned long context_id;
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phys_addr_t target_pc;
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cpu_id = vcpu_get_reg(source_vcpu, 1) & MPIDR_HWID_BITMASK;
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if (vcpu_mode_is_32bit(source_vcpu))
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cpu_id &= ~((u32) 0);
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vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
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/*
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* Make sure the caller requested a valid CPU and that the CPU is
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* turned off.
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*/
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if (!vcpu)
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return PSCI_RET_INVALID_PARAMS;
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if (!vcpu->arch.power_off) {
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if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
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return PSCI_RET_ALREADY_ON;
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else
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return PSCI_RET_INVALID_PARAMS;
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}
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target_pc = vcpu_get_reg(source_vcpu, 2);
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context_id = vcpu_get_reg(source_vcpu, 3);
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kvm_reset_vcpu(vcpu);
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/* Gracefully handle Thumb2 entry point */
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if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
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target_pc &= ~((phys_addr_t) 1);
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vcpu_set_thumb(vcpu);
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}
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/* Propagate caller endianness */
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if (kvm_vcpu_is_be(source_vcpu))
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kvm_vcpu_set_be(vcpu);
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*vcpu_pc(vcpu) = target_pc;
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/*
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* NOTE: We always update r0 (or x0) because for PSCI v0.1
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* the general puspose registers are undefined upon CPU_ON.
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*/
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vcpu_set_reg(vcpu, 0, context_id);
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vcpu->arch.power_off = false;
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smp_mb(); /* Make sure the above is visible */
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wq = kvm_arch_vcpu_wq(vcpu);
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swake_up(wq);
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return PSCI_RET_SUCCESS;
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}
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static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
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{
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int i, matching_cpus = 0;
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unsigned long mpidr;
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unsigned long target_affinity;
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unsigned long target_affinity_mask;
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unsigned long lowest_affinity_level;
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struct kvm *kvm = vcpu->kvm;
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struct kvm_vcpu *tmp;
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target_affinity = vcpu_get_reg(vcpu, 1);
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lowest_affinity_level = vcpu_get_reg(vcpu, 2);
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/* Determine target affinity mask */
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target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
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if (!target_affinity_mask)
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return PSCI_RET_INVALID_PARAMS;
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/* Ignore other bits of target affinity */
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target_affinity &= target_affinity_mask;
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/*
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* If one or more VCPU matching target affinity are running
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* then ON else OFF
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*/
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kvm_for_each_vcpu(i, tmp, kvm) {
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mpidr = kvm_vcpu_get_mpidr_aff(tmp);
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if ((mpidr & target_affinity_mask) == target_affinity) {
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matching_cpus++;
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if (!tmp->arch.power_off)
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return PSCI_0_2_AFFINITY_LEVEL_ON;
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}
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}
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if (!matching_cpus)
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return PSCI_RET_INVALID_PARAMS;
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return PSCI_0_2_AFFINITY_LEVEL_OFF;
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}
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static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
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{
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int i;
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struct kvm_vcpu *tmp;
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/*
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* The KVM ABI specifies that a system event exit may call KVM_RUN
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* again and may perform shutdown/reboot at a later time that when the
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* actual request is made. Since we are implementing PSCI and a
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* caller of PSCI reboot and shutdown expects that the system shuts
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* down or reboots immediately, let's make sure that VCPUs are not run
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* after this call is handled and before the VCPUs have been
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* re-initialized.
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*/
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kvm_for_each_vcpu(i, tmp, vcpu->kvm)
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tmp->arch.power_off = true;
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kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
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memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
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vcpu->run->system_event.type = type;
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vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
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}
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static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
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{
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kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
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}
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static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
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{
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kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
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}
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int kvm_psci_version(struct kvm_vcpu *vcpu)
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{
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if (test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features))
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return KVM_ARM_PSCI_0_2;
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return KVM_ARM_PSCI_0_1;
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}
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static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
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{
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struct kvm *kvm = vcpu->kvm;
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unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
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unsigned long val;
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int ret = 1;
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switch (psci_fn) {
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case PSCI_0_2_FN_PSCI_VERSION:
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/*
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* Bits[31:16] = Major Version = 0
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* Bits[15:0] = Minor Version = 2
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*/
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val = 2;
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break;
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case PSCI_0_2_FN_CPU_SUSPEND:
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case PSCI_0_2_FN64_CPU_SUSPEND:
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val = kvm_psci_vcpu_suspend(vcpu);
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break;
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case PSCI_0_2_FN_CPU_OFF:
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kvm_psci_vcpu_off(vcpu);
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val = PSCI_RET_SUCCESS;
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break;
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case PSCI_0_2_FN_CPU_ON:
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case PSCI_0_2_FN64_CPU_ON:
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mutex_lock(&kvm->lock);
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val = kvm_psci_vcpu_on(vcpu);
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mutex_unlock(&kvm->lock);
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break;
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case PSCI_0_2_FN_AFFINITY_INFO:
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case PSCI_0_2_FN64_AFFINITY_INFO:
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val = kvm_psci_vcpu_affinity_info(vcpu);
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break;
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case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
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/*
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* Trusted OS is MP hence does not require migration
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* or
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* Trusted OS is not present
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*/
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val = PSCI_0_2_TOS_MP;
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break;
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case PSCI_0_2_FN_SYSTEM_OFF:
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kvm_psci_system_off(vcpu);
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/*
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* We should'nt be going back to guest VCPU after
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* receiving SYSTEM_OFF request.
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*
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* If user space accidently/deliberately resumes
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* guest VCPU after SYSTEM_OFF request then guest
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* VCPU should see internal failure from PSCI return
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* value. To achieve this, we preload r0 (or x0) with
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* PSCI return value INTERNAL_FAILURE.
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*/
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val = PSCI_RET_INTERNAL_FAILURE;
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ret = 0;
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break;
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case PSCI_0_2_FN_SYSTEM_RESET:
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kvm_psci_system_reset(vcpu);
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/*
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* Same reason as SYSTEM_OFF for preloading r0 (or x0)
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* with PSCI return value INTERNAL_FAILURE.
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*/
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val = PSCI_RET_INTERNAL_FAILURE;
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ret = 0;
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break;
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default:
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val = PSCI_RET_NOT_SUPPORTED;
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break;
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}
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vcpu_set_reg(vcpu, 0, val);
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return ret;
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}
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static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
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{
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struct kvm *kvm = vcpu->kvm;
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unsigned long psci_fn = vcpu_get_reg(vcpu, 0) & ~((u32) 0);
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unsigned long val;
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switch (psci_fn) {
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case KVM_PSCI_FN_CPU_OFF:
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kvm_psci_vcpu_off(vcpu);
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val = PSCI_RET_SUCCESS;
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break;
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case KVM_PSCI_FN_CPU_ON:
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mutex_lock(&kvm->lock);
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val = kvm_psci_vcpu_on(vcpu);
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mutex_unlock(&kvm->lock);
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break;
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default:
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val = PSCI_RET_NOT_SUPPORTED;
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break;
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}
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vcpu_set_reg(vcpu, 0, val);
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return 1;
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}
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/**
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* kvm_psci_call - handle PSCI call if r0 value is in range
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* @vcpu: Pointer to the VCPU struct
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*
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* Handle PSCI calls from guests through traps from HVC instructions.
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* The calling convention is similar to SMC calls to the secure world
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* where the function number is placed in r0.
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*
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* This function returns: > 0 (success), 0 (success but exit to user
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* space), and < 0 (errors)
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*
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* Errors:
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* -EINVAL: Unrecognized PSCI function
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*/
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int kvm_psci_call(struct kvm_vcpu *vcpu)
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{
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switch (kvm_psci_version(vcpu)) {
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case KVM_ARM_PSCI_0_2:
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return kvm_psci_0_2_call(vcpu);
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case KVM_ARM_PSCI_0_1:
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return kvm_psci_0_1_call(vcpu);
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default:
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return -EINVAL;
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};
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}
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