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![Alexander Graf](/assets/img/avatar_default.png)
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>
339 lines
8.3 KiB
C
339 lines
8.3 KiB
C
/*
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* Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
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*
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* Authors:
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* Alexander Graf <agraf@suse.de>
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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, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <linux/kvm_host.h>
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#include <linux/hash.h>
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#include <linux/slab.h>
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#include "trace.h"
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#include <asm/kvm_ppc.h>
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#include <asm/kvm_book3s.h>
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#include <asm/machdep.h>
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#include <asm/mmu_context.h>
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#include <asm/hw_irq.h>
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#define PTE_SIZE 12
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static struct kmem_cache *hpte_cache;
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static inline u64 kvmppc_mmu_hash_pte(u64 eaddr)
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{
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return hash_64(eaddr >> PTE_SIZE, HPTEG_HASH_BITS_PTE);
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}
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static inline u64 kvmppc_mmu_hash_pte_long(u64 eaddr)
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{
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return hash_64((eaddr & 0x0ffff000) >> PTE_SIZE,
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HPTEG_HASH_BITS_PTE_LONG);
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}
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static inline u64 kvmppc_mmu_hash_vpte(u64 vpage)
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{
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return hash_64(vpage & 0xfffffffffULL, HPTEG_HASH_BITS_VPTE);
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}
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static inline u64 kvmppc_mmu_hash_vpte_long(u64 vpage)
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{
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return hash_64((vpage & 0xffffff000ULL) >> 12,
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HPTEG_HASH_BITS_VPTE_LONG);
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}
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void kvmppc_mmu_hpte_cache_map(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
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{
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u64 index;
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trace_kvm_book3s_mmu_map(pte);
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spin_lock(&vcpu->arch.mmu_lock);
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/* Add to ePTE list */
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index = kvmppc_mmu_hash_pte(pte->pte.eaddr);
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hlist_add_head_rcu(&pte->list_pte, &vcpu->arch.hpte_hash_pte[index]);
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/* Add to ePTE_long list */
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index = kvmppc_mmu_hash_pte_long(pte->pte.eaddr);
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hlist_add_head_rcu(&pte->list_pte_long,
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&vcpu->arch.hpte_hash_pte_long[index]);
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/* Add to vPTE list */
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index = kvmppc_mmu_hash_vpte(pte->pte.vpage);
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hlist_add_head_rcu(&pte->list_vpte, &vcpu->arch.hpte_hash_vpte[index]);
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/* Add to vPTE_long list */
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index = kvmppc_mmu_hash_vpte_long(pte->pte.vpage);
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hlist_add_head_rcu(&pte->list_vpte_long,
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&vcpu->arch.hpte_hash_vpte_long[index]);
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spin_unlock(&vcpu->arch.mmu_lock);
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}
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static void free_pte_rcu(struct rcu_head *head)
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{
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struct hpte_cache *pte = container_of(head, struct hpte_cache, rcu_head);
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kmem_cache_free(hpte_cache, pte);
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}
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static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
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{
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trace_kvm_book3s_mmu_invalidate(pte);
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/* Different for 32 and 64 bit */
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kvmppc_mmu_invalidate_pte(vcpu, 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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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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static void kvmppc_mmu_pte_flush_all(struct kvm_vcpu *vcpu)
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{
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struct hpte_cache *pte;
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struct hlist_node *node;
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int i;
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rcu_read_lock();
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for (i = 0; i < HPTEG_HASH_NUM_VPTE_LONG; i++) {
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struct hlist_head *list = &vcpu->arch.hpte_hash_vpte_long[i];
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hlist_for_each_entry_rcu(pte, node, list, list_vpte_long)
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invalidate_pte(vcpu, pte);
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}
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rcu_read_unlock();
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}
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static void kvmppc_mmu_pte_flush_page(struct kvm_vcpu *vcpu, ulong guest_ea)
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{
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struct hlist_head *list;
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struct hlist_node *node;
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struct hpte_cache *pte;
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/* Find the list of entries in the map */
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list = &vcpu->arch.hpte_hash_pte[kvmppc_mmu_hash_pte(guest_ea)];
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rcu_read_lock();
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/* Check the list for matching entries and invalidate */
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hlist_for_each_entry_rcu(pte, node, list, list_pte)
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if ((pte->pte.eaddr & ~0xfffUL) == guest_ea)
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invalidate_pte(vcpu, pte);
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rcu_read_unlock();
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}
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static void kvmppc_mmu_pte_flush_long(struct kvm_vcpu *vcpu, ulong guest_ea)
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{
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struct hlist_head *list;
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struct hlist_node *node;
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struct hpte_cache *pte;
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/* Find the list of entries in the map */
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list = &vcpu->arch.hpte_hash_pte_long[
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kvmppc_mmu_hash_pte_long(guest_ea)];
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rcu_read_lock();
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/* Check the list for matching entries and invalidate */
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hlist_for_each_entry_rcu(pte, node, list, list_pte_long)
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if ((pte->pte.eaddr & 0x0ffff000UL) == guest_ea)
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invalidate_pte(vcpu, pte);
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rcu_read_unlock();
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}
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void kvmppc_mmu_pte_flush(struct kvm_vcpu *vcpu, ulong guest_ea, ulong ea_mask)
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{
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trace_kvm_book3s_mmu_flush("", vcpu, guest_ea, ea_mask);
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guest_ea &= ea_mask;
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switch (ea_mask) {
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case ~0xfffUL:
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kvmppc_mmu_pte_flush_page(vcpu, guest_ea);
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break;
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case 0x0ffff000:
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kvmppc_mmu_pte_flush_long(vcpu, guest_ea);
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break;
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case 0:
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/* Doing a complete flush -> start from scratch */
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kvmppc_mmu_pte_flush_all(vcpu);
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break;
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default:
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WARN_ON(1);
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break;
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}
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}
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/* Flush with mask 0xfffffffff */
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static void kvmppc_mmu_pte_vflush_short(struct kvm_vcpu *vcpu, u64 guest_vp)
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{
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struct hlist_head *list;
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struct hlist_node *node;
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struct hpte_cache *pte;
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u64 vp_mask = 0xfffffffffULL;
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list = &vcpu->arch.hpte_hash_vpte[kvmppc_mmu_hash_vpte(guest_vp)];
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rcu_read_lock();
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/* Check the list for matching entries and invalidate */
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hlist_for_each_entry_rcu(pte, node, list, list_vpte)
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if ((pte->pte.vpage & vp_mask) == guest_vp)
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invalidate_pte(vcpu, pte);
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rcu_read_unlock();
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}
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/* Flush with mask 0xffffff000 */
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static void kvmppc_mmu_pte_vflush_long(struct kvm_vcpu *vcpu, u64 guest_vp)
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{
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struct hlist_head *list;
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struct hlist_node *node;
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struct hpte_cache *pte;
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u64 vp_mask = 0xffffff000ULL;
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list = &vcpu->arch.hpte_hash_vpte_long[
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kvmppc_mmu_hash_vpte_long(guest_vp)];
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rcu_read_lock();
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/* Check the list for matching entries and invalidate */
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hlist_for_each_entry_rcu(pte, node, list, list_vpte_long)
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if ((pte->pte.vpage & vp_mask) == guest_vp)
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invalidate_pte(vcpu, pte);
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rcu_read_unlock();
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}
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void kvmppc_mmu_pte_vflush(struct kvm_vcpu *vcpu, u64 guest_vp, u64 vp_mask)
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{
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trace_kvm_book3s_mmu_flush("v", vcpu, guest_vp, vp_mask);
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guest_vp &= vp_mask;
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switch(vp_mask) {
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case 0xfffffffffULL:
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kvmppc_mmu_pte_vflush_short(vcpu, guest_vp);
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break;
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case 0xffffff000ULL:
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kvmppc_mmu_pte_vflush_long(vcpu, guest_vp);
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break;
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default:
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WARN_ON(1);
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return;
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}
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}
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void kvmppc_mmu_pte_pflush(struct kvm_vcpu *vcpu, ulong pa_start, ulong pa_end)
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{
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struct hlist_node *node;
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struct hpte_cache *pte;
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int i;
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trace_kvm_book3s_mmu_flush("p", vcpu, pa_start, pa_end);
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rcu_read_lock();
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for (i = 0; i < HPTEG_HASH_NUM_VPTE_LONG; i++) {
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struct hlist_head *list = &vcpu->arch.hpte_hash_vpte_long[i];
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hlist_for_each_entry_rcu(pte, node, list, list_vpte_long)
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if ((pte->pte.raddr >= pa_start) &&
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(pte->pte.raddr < pa_end))
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invalidate_pte(vcpu, pte);
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}
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rcu_read_unlock();
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}
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struct hpte_cache *kvmppc_mmu_hpte_cache_next(struct kvm_vcpu *vcpu)
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{
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struct hpte_cache *pte;
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pte = kmem_cache_zalloc(hpte_cache, GFP_KERNEL);
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vcpu->arch.hpte_cache_count++;
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if (vcpu->arch.hpte_cache_count == HPTEG_CACHE_NUM)
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kvmppc_mmu_pte_flush_all(vcpu);
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return pte;
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}
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void kvmppc_mmu_hpte_destroy(struct kvm_vcpu *vcpu)
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{
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kvmppc_mmu_pte_flush(vcpu, 0, 0);
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}
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static void kvmppc_mmu_hpte_init_hash(struct hlist_head *hash_list, int len)
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{
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int i;
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for (i = 0; i < len; i++)
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INIT_HLIST_HEAD(&hash_list[i]);
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}
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int kvmppc_mmu_hpte_init(struct kvm_vcpu *vcpu)
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{
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/* init hpte lookup hashes */
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kvmppc_mmu_hpte_init_hash(vcpu->arch.hpte_hash_pte,
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ARRAY_SIZE(vcpu->arch.hpte_hash_pte));
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kvmppc_mmu_hpte_init_hash(vcpu->arch.hpte_hash_pte_long,
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ARRAY_SIZE(vcpu->arch.hpte_hash_pte_long));
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kvmppc_mmu_hpte_init_hash(vcpu->arch.hpte_hash_vpte,
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ARRAY_SIZE(vcpu->arch.hpte_hash_vpte));
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kvmppc_mmu_hpte_init_hash(vcpu->arch.hpte_hash_vpte_long,
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ARRAY_SIZE(vcpu->arch.hpte_hash_vpte_long));
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spin_lock_init(&vcpu->arch.mmu_lock);
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return 0;
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}
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int kvmppc_mmu_hpte_sysinit(void)
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{
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/* init hpte slab cache */
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hpte_cache = kmem_cache_create("kvm-spt", sizeof(struct hpte_cache),
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sizeof(struct hpte_cache), 0, NULL);
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return 0;
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}
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void kvmppc_mmu_hpte_sysexit(void)
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{
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kmem_cache_destroy(hpte_cache);
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}
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