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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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24a7f67575
Currently, kvmtool unconditionally declares that HVC should be used to call PSCI, so the function numbers in the DT tell the guest nothing about the function ID namespace or calling convention for SMC. We already assume that the guest will examine and honour the DT, since there is no way it could possibly guess the KVM-specific PSCI function IDs otherwise. So let's not encourage guests to violate what's specified in the DT by using SMC to make the call. [ Modified to apply to top of kvm/arm tree - Christoffer ] Signed-off-by: Dave P Martin <Dave.Martin@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
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 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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