forked from Minki/linux
aa024c2f35
Implement the PSCI specification (ARM DEN 0022A) to control virtual CPUs being "powered" on or off. PSCI/KVM is detected using the KVM_CAP_ARM_PSCI capability. A virtual CPU can now be initialized in a "powered off" state, using the KVM_ARM_VCPU_POWER_OFF feature flag. The guest can use either SMC or HVC to execute a PSCI function. Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
109 lines
2.7 KiB
C
109 lines
2.7 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/kvm_host.h>
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#include <linux/wait.h>
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#include <asm/kvm_emulate.h>
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#include <asm/kvm_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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static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
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{
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vcpu->arch.pause = true;
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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;
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wait_queue_head_t *wq;
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unsigned long cpu_id;
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phys_addr_t target_pc;
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cpu_id = *vcpu_reg(source_vcpu, 1);
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if (vcpu_mode_is_32bit(source_vcpu))
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cpu_id &= ~((u32) 0);
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if (cpu_id >= atomic_read(&kvm->online_vcpus))
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return KVM_PSCI_RET_INVAL;
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target_pc = *vcpu_reg(source_vcpu, 2);
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vcpu = kvm_get_vcpu(kvm, cpu_id);
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wq = kvm_arch_vcpu_wq(vcpu);
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if (!waitqueue_active(wq))
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return KVM_PSCI_RET_INVAL;
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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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*vcpu_pc(vcpu) = target_pc;
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vcpu->arch.pause = false;
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smp_mb(); /* Make sure the above is visible */
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wake_up_interruptible(wq);
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return KVM_PSCI_RET_SUCCESS;
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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 or SMC instructions.
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* The calling convention is similar to SMC calls to the secure world where
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* the function number is placed in r0 and this function returns true if the
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* function number specified in r0 is withing the PSCI range, and false
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* otherwise.
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*/
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bool kvm_psci_call(struct kvm_vcpu *vcpu)
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{
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unsigned long psci_fn = *vcpu_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 = KVM_PSCI_RET_SUCCESS;
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break;
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case KVM_PSCI_FN_CPU_ON:
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val = kvm_psci_vcpu_on(vcpu);
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break;
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case KVM_PSCI_FN_CPU_SUSPEND:
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case KVM_PSCI_FN_MIGRATE:
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val = KVM_PSCI_RET_NI;
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break;
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default:
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return false;
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}
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*vcpu_reg(vcpu, 0) = val;
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return true;
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}
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