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KVM: PPC: Book3S HV: Fix check for running inside guest in global_invalidates()
The global_invalidates() function contains a check that is intended to tell whether we are currently executing in the context of a hypercall issued by the guest. The reason is that the optimization of using a local TLB invalidate instruction is only valid in that context. The check was testing local_paca->kvm_hstate.kvm_vcore, which gets set when entering the guest but no longer gets cleared when exiting the guest. To fix this, we use the kvm_vcpu field instead, which does get cleared when exiting the guest, by the kvmppc_release_hwthread() calls inside kvmppc_run_core(). The effect of having the check wrong was that when kvmppc_do_h_remove() got called from htab_write() on the destination machine during a migration, it cleared the current cpu's bit in kvm->arch.need_tlb_flush. This meant that when the guest started running in the destination VM, it may miss out on doing a complete TLB flush, and therefore may end up using stale TLB entries from a previous guest that used the same LPID value. This should make migration more reliable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
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1 changed files with 2 additions and 1 deletions
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@ -42,13 +42,14 @@ static int global_invalidates(struct kvm *kvm, unsigned long flags)
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/*
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* If there is only one vcore, and it's currently running,
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* as indicated by local_paca->kvm_hstate.kvm_vcpu being set,
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* we can use tlbiel as long as we mark all other physical
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* cores as potentially having stale TLB entries for this lpid.
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* If we're not using MMU notifiers, we never take pages away
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* from the guest, so we can use tlbiel if requested.
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* Otherwise, don't use tlbiel.
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*/
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if (kvm->arch.online_vcores == 1 && local_paca->kvm_hstate.kvm_vcore)
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if (kvm->arch.online_vcores == 1 && local_paca->kvm_hstate.kvm_vcpu)
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global = 0;
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else if (kvm->arch.using_mmu_notifiers)
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global = 1;
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