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![Alexander Graf](/assets/img/avatar_default.png)
When running the 64-bit Book3s PR code without CONFIG_PREEMPT_NONE, we were doing a few things wrong, most notably access to PACA fields without making sure that the pointers stay stable accross the access (preempt_disable()). This patch moves to_svcpu towards a get/put model which allows us to disable preemption while accessing the shadow vcpu fields in the PACA. That way we can run preemptible and everyone's happy! Reported-by: Jörg Sommer <joerg@alea.gnuu.de> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
329 lines
8.3 KiB
C
329 lines
8.3 KiB
C
/*
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* Copyright (C) 2009 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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* Kevin Wolf <mail@kevin-wolf.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 <asm/kvm_ppc.h>
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#include <asm/kvm_book3s.h>
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#include <asm/mmu-hash64.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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#include "trace.h"
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#define PTE_SIZE 12
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void kvmppc_mmu_invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
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{
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ppc_md.hpte_invalidate(pte->slot, pte->host_va,
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MMU_PAGE_4K, MMU_SEGSIZE_256M,
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false);
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}
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/* We keep 512 gvsid->hvsid entries, mapping the guest ones to the array using
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* a hash, so we don't waste cycles on looping */
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static u16 kvmppc_sid_hash(struct kvm_vcpu *vcpu, u64 gvsid)
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{
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return (u16)(((gvsid >> (SID_MAP_BITS * 7)) & SID_MAP_MASK) ^
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((gvsid >> (SID_MAP_BITS * 6)) & SID_MAP_MASK) ^
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((gvsid >> (SID_MAP_BITS * 5)) & SID_MAP_MASK) ^
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((gvsid >> (SID_MAP_BITS * 4)) & SID_MAP_MASK) ^
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((gvsid >> (SID_MAP_BITS * 3)) & SID_MAP_MASK) ^
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((gvsid >> (SID_MAP_BITS * 2)) & SID_MAP_MASK) ^
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((gvsid >> (SID_MAP_BITS * 1)) & SID_MAP_MASK) ^
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((gvsid >> (SID_MAP_BITS * 0)) & SID_MAP_MASK));
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}
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static struct kvmppc_sid_map *find_sid_vsid(struct kvm_vcpu *vcpu, u64 gvsid)
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{
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struct kvmppc_sid_map *map;
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u16 sid_map_mask;
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if (vcpu->arch.shared->msr & MSR_PR)
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gvsid |= VSID_PR;
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sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
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map = &to_book3s(vcpu)->sid_map[sid_map_mask];
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if (map->valid && (map->guest_vsid == gvsid)) {
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trace_kvm_book3s_slb_found(gvsid, map->host_vsid);
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return map;
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}
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map = &to_book3s(vcpu)->sid_map[SID_MAP_MASK - sid_map_mask];
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if (map->valid && (map->guest_vsid == gvsid)) {
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trace_kvm_book3s_slb_found(gvsid, map->host_vsid);
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return map;
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}
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trace_kvm_book3s_slb_fail(sid_map_mask, gvsid);
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return NULL;
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}
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int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte)
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{
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pfn_t hpaddr;
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ulong hash, hpteg, va;
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u64 vsid;
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int ret;
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int rflags = 0x192;
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int vflags = 0;
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int attempt = 0;
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struct kvmppc_sid_map *map;
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int r = 0;
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/* Get host physical address for gpa */
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hpaddr = kvmppc_gfn_to_pfn(vcpu, orig_pte->raddr >> PAGE_SHIFT);
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if (is_error_pfn(hpaddr)) {
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printk(KERN_INFO "Couldn't get guest page for gfn %lx!\n", orig_pte->eaddr);
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r = -EINVAL;
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goto out;
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}
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hpaddr <<= PAGE_SHIFT;
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hpaddr |= orig_pte->raddr & (~0xfffULL & ~PAGE_MASK);
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/* and write the mapping ea -> hpa into the pt */
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vcpu->arch.mmu.esid_to_vsid(vcpu, orig_pte->eaddr >> SID_SHIFT, &vsid);
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map = find_sid_vsid(vcpu, vsid);
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if (!map) {
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ret = kvmppc_mmu_map_segment(vcpu, orig_pte->eaddr);
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WARN_ON(ret < 0);
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map = find_sid_vsid(vcpu, vsid);
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}
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if (!map) {
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printk(KERN_ERR "KVM: Segment map for 0x%llx (0x%lx) failed\n",
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vsid, orig_pte->eaddr);
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WARN_ON(true);
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r = -EINVAL;
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goto out;
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}
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vsid = map->host_vsid;
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va = hpt_va(orig_pte->eaddr, vsid, MMU_SEGSIZE_256M);
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if (!orig_pte->may_write)
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rflags |= HPTE_R_PP;
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else
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mark_page_dirty(vcpu->kvm, orig_pte->raddr >> PAGE_SHIFT);
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if (!orig_pte->may_execute)
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rflags |= HPTE_R_N;
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hash = hpt_hash(va, PTE_SIZE, MMU_SEGSIZE_256M);
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map_again:
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hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
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/* In case we tried normal mapping already, let's nuke old entries */
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if (attempt > 1)
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if (ppc_md.hpte_remove(hpteg) < 0) {
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r = -1;
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goto out;
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}
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ret = ppc_md.hpte_insert(hpteg, va, hpaddr, rflags, vflags, MMU_PAGE_4K, MMU_SEGSIZE_256M);
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if (ret < 0) {
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/* If we couldn't map a primary PTE, try a secondary */
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hash = ~hash;
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vflags ^= HPTE_V_SECONDARY;
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attempt++;
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goto map_again;
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} else {
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struct hpte_cache *pte = kvmppc_mmu_hpte_cache_next(vcpu);
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trace_kvm_book3s_64_mmu_map(rflags, hpteg, va, hpaddr, orig_pte);
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/* The ppc_md code may give us a secondary entry even though we
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asked for a primary. Fix up. */
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if ((ret & _PTEIDX_SECONDARY) && !(vflags & HPTE_V_SECONDARY)) {
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hash = ~hash;
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hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
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}
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pte->slot = hpteg + (ret & 7);
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pte->host_va = va;
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pte->pte = *orig_pte;
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pte->pfn = hpaddr >> PAGE_SHIFT;
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kvmppc_mmu_hpte_cache_map(vcpu, pte);
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}
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out:
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return r;
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}
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static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
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{
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struct kvmppc_sid_map *map;
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struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
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u16 sid_map_mask;
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static int backwards_map = 0;
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if (vcpu->arch.shared->msr & MSR_PR)
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gvsid |= VSID_PR;
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/* We might get collisions that trap in preceding order, so let's
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map them differently */
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sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
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if (backwards_map)
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sid_map_mask = SID_MAP_MASK - sid_map_mask;
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map = &to_book3s(vcpu)->sid_map[sid_map_mask];
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/* Make sure we're taking the other map next time */
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backwards_map = !backwards_map;
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/* Uh-oh ... out of mappings. Let's flush! */
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if (vcpu_book3s->vsid_next == vcpu_book3s->vsid_max) {
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vcpu_book3s->vsid_next = vcpu_book3s->vsid_first;
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memset(vcpu_book3s->sid_map, 0,
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sizeof(struct kvmppc_sid_map) * SID_MAP_NUM);
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kvmppc_mmu_pte_flush(vcpu, 0, 0);
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kvmppc_mmu_flush_segments(vcpu);
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}
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map->host_vsid = vcpu_book3s->vsid_next++;
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map->guest_vsid = gvsid;
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map->valid = true;
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trace_kvm_book3s_slb_map(sid_map_mask, gvsid, map->host_vsid);
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return map;
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}
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static int kvmppc_mmu_next_segment(struct kvm_vcpu *vcpu, ulong esid)
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{
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struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
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int i;
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int max_slb_size = 64;
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int found_inval = -1;
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int r;
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if (!svcpu->slb_max)
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svcpu->slb_max = 1;
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/* Are we overwriting? */
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for (i = 1; i < svcpu->slb_max; i++) {
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if (!(svcpu->slb[i].esid & SLB_ESID_V))
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found_inval = i;
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else if ((svcpu->slb[i].esid & ESID_MASK) == esid) {
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r = i;
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goto out;
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}
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}
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/* Found a spare entry that was invalidated before */
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if (found_inval > 0) {
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r = found_inval;
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goto out;
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}
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/* No spare invalid entry, so create one */
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if (mmu_slb_size < 64)
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max_slb_size = mmu_slb_size;
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/* Overflowing -> purge */
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if ((svcpu->slb_max) == max_slb_size)
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kvmppc_mmu_flush_segments(vcpu);
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r = svcpu->slb_max;
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svcpu->slb_max++;
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out:
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svcpu_put(svcpu);
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return r;
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}
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int kvmppc_mmu_map_segment(struct kvm_vcpu *vcpu, ulong eaddr)
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{
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struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
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u64 esid = eaddr >> SID_SHIFT;
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u64 slb_esid = (eaddr & ESID_MASK) | SLB_ESID_V;
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u64 slb_vsid = SLB_VSID_USER;
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u64 gvsid;
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int slb_index;
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struct kvmppc_sid_map *map;
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int r = 0;
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slb_index = kvmppc_mmu_next_segment(vcpu, eaddr & ESID_MASK);
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if (vcpu->arch.mmu.esid_to_vsid(vcpu, esid, &gvsid)) {
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/* Invalidate an entry */
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svcpu->slb[slb_index].esid = 0;
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r = -ENOENT;
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goto out;
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}
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map = find_sid_vsid(vcpu, gvsid);
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if (!map)
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map = create_sid_map(vcpu, gvsid);
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map->guest_esid = esid;
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slb_vsid |= (map->host_vsid << 12);
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slb_vsid &= ~SLB_VSID_KP;
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slb_esid |= slb_index;
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svcpu->slb[slb_index].esid = slb_esid;
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svcpu->slb[slb_index].vsid = slb_vsid;
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trace_kvm_book3s_slbmte(slb_vsid, slb_esid);
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out:
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svcpu_put(svcpu);
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return r;
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}
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void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
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{
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struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
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svcpu->slb_max = 1;
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svcpu->slb[0].esid = 0;
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svcpu_put(svcpu);
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}
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void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
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{
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kvmppc_mmu_hpte_destroy(vcpu);
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__destroy_context(to_book3s(vcpu)->context_id[0]);
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}
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int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
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{
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struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
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int err;
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err = __init_new_context();
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if (err < 0)
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return -1;
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vcpu3s->context_id[0] = err;
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vcpu3s->vsid_max = ((vcpu3s->context_id[0] + 1) << USER_ESID_BITS) - 1;
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vcpu3s->vsid_first = vcpu3s->context_id[0] << USER_ESID_BITS;
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vcpu3s->vsid_next = vcpu3s->vsid_first;
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kvmppc_mmu_hpte_init(vcpu);
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return 0;
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}
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