forked from luck/tmp_suning_uos_patched
KVM: PPC: Make invalidation code more reliable
There is a race condition in the pte invalidation code path where we can't be sure if a pte was invalidated already. So let's move the spin lock around to get rid of the race. Signed-off-by: Alexander Graf <agraf@suse.de>
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@ -92,10 +92,6 @@ static void free_pte_rcu(struct rcu_head *head)
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static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
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{
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/* pte already invalidated? */
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if (hlist_unhashed(&pte->list_pte))
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return;
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trace_kvm_book3s_mmu_invalidate(pte);
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/* Different for 32 and 64 bit */
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@ -103,18 +99,24 @@ static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
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spin_lock(&vcpu->arch.mmu_lock);
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/* pte already invalidated in between? */
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if (hlist_unhashed(&pte->list_pte)) {
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spin_unlock(&vcpu->arch.mmu_lock);
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return;
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}
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hlist_del_init_rcu(&pte->list_pte);
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hlist_del_init_rcu(&pte->list_pte_long);
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hlist_del_init_rcu(&pte->list_vpte);
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hlist_del_init_rcu(&pte->list_vpte_long);
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spin_unlock(&vcpu->arch.mmu_lock);
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if (pte->pte.may_write)
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kvm_release_pfn_dirty(pte->pfn);
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else
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kvm_release_pfn_clean(pte->pfn);
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spin_unlock(&vcpu->arch.mmu_lock);
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vcpu->arch.hpte_cache_count--;
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call_rcu(&pte->rcu_head, free_pte_rcu);
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}
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