/*
   * Copyright (C) 2009 SUSE Linux Products GmbH. All rights reserved.
   *
   * Authors:
   *     Alexander Graf <agraf@suse.de>
   *     Kevin Wolf <mail@kevin-wolf.de>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License, version 2, as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
   */
  
  #include <linux/kvm_host.h>
  
  #include <asm/kvm_ppc.h>
  #include <asm/kvm_book3s.h>
  #include <asm/mmu-hash64.h>
  #include <asm/machdep.h>
  #include <asm/mmu_context.h>
  #include <asm/hw_irq.h>

  #include "trace.h"

  
  #define PTE_SIZE 12

  void kvmppc_mmu_invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)

  {

  	ppc_md.hpte_invalidate(pte->slot, pte->host_va,
  			       MMU_PAGE_4K, MMU_SEGSIZE_256M,
  			       false);

  }
  
  /* We keep 512 gvsid->hvsid entries, mapping the guest ones to the array using
   * a hash, so we don't waste cycles on looping */
  static u16 kvmppc_sid_hash(struct kvm_vcpu *vcpu, u64 gvsid)
  {

  	return (u16)(((gvsid >> (SID_MAP_BITS * 7)) & SID_MAP_MASK) ^
  		     ((gvsid >> (SID_MAP_BITS * 6)) & SID_MAP_MASK) ^
  		     ((gvsid >> (SID_MAP_BITS * 5)) & SID_MAP_MASK) ^
  		     ((gvsid >> (SID_MAP_BITS * 4)) & SID_MAP_MASK) ^
  		     ((gvsid >> (SID_MAP_BITS * 3)) & SID_MAP_MASK) ^
  		     ((gvsid >> (SID_MAP_BITS * 2)) & SID_MAP_MASK) ^
  		     ((gvsid >> (SID_MAP_BITS * 1)) & SID_MAP_MASK) ^
  		     ((gvsid >> (SID_MAP_BITS * 0)) & SID_MAP_MASK));

  }

  static struct kvmppc_sid_map *find_sid_vsid(struct kvm_vcpu *vcpu, u64 gvsid)
  {
  	struct kvmppc_sid_map *map;
  	u16 sid_map_mask;

  	if (vcpu->arch.shared->msr & MSR_PR)

  		gvsid |= VSID_PR;
  
  	sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
  	map = &to_book3s(vcpu)->sid_map[sid_map_mask];

  	if (map->valid && (map->guest_vsid == gvsid)) {

  		trace_kvm_book3s_slb_found(gvsid, map->host_vsid);

  		return map;
  	}
  
  	map = &to_book3s(vcpu)->sid_map[SID_MAP_MASK - sid_map_mask];

  	if (map->valid && (map->guest_vsid == gvsid)) {

  		trace_kvm_book3s_slb_found(gvsid, map->host_vsid);

  		return map;
  	}

  	trace_kvm_book3s_slb_fail(sid_map_mask, gvsid);

  	return NULL;
  }
  
  int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte)
  {
  	pfn_t hpaddr;
  	ulong hash, hpteg, va;
  	u64 vsid;
  	int ret;
  	int rflags = 0x192;
  	int vflags = 0;
  	int attempt = 0;
  	struct kvmppc_sid_map *map;
  
  	/* Get host physical address for gpa */

  	hpaddr = kvmppc_gfn_to_pfn(vcpu, orig_pte->raddr >> PAGE_SHIFT);

  	if (is_error_pfn(hpaddr)) {

  		printk(KERN_INFO "Couldn't get guest page for gfn %lx!
  ", orig_pte->eaddr);

  		return -EINVAL;
  	}
  	hpaddr <<= PAGE_SHIFT;

  	hpaddr |= orig_pte->raddr & (~0xfffULL & ~PAGE_MASK);

  
  	/* and write the mapping ea -> hpa into the pt */
  	vcpu->arch.mmu.esid_to_vsid(vcpu, orig_pte->eaddr >> SID_SHIFT, &vsid);
  	map = find_sid_vsid(vcpu, vsid);
  	if (!map) {

  		ret = kvmppc_mmu_map_segment(vcpu, orig_pte->eaddr);
  		WARN_ON(ret < 0);

  		map = find_sid_vsid(vcpu, vsid);
  	}

  	if (!map) {
  		printk(KERN_ERR "KVM: Segment map for 0x%llx (0x%lx) failed
  ",
  				vsid, orig_pte->eaddr);
  		WARN_ON(true);
  		return -EINVAL;
  	}

  
  	vsid = map->host_vsid;
  	va = hpt_va(orig_pte->eaddr, vsid, MMU_SEGSIZE_256M);
  
  	if (!orig_pte->may_write)
  		rflags |= HPTE_R_PP;
  	else
  		mark_page_dirty(vcpu->kvm, orig_pte->raddr >> PAGE_SHIFT);
  
  	if (!orig_pte->may_execute)
  		rflags |= HPTE_R_N;
  
  	hash = hpt_hash(va, PTE_SIZE, MMU_SEGSIZE_256M);
  
  map_again:
  	hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
  
  	/* In case we tried normal mapping already, let's nuke old entries */
  	if (attempt > 1)
  		if (ppc_md.hpte_remove(hpteg) < 0)
  			return -1;
  
  	ret = ppc_md.hpte_insert(hpteg, va, hpaddr, rflags, vflags, MMU_PAGE_4K, MMU_SEGSIZE_256M);
  
  	if (ret < 0) {
  		/* If we couldn't map a primary PTE, try a secondary */

  		hash = ~hash;

  		vflags ^= HPTE_V_SECONDARY;

  		attempt++;

  		goto map_again;
  	} else {

  		struct hpte_cache *pte = kvmppc_mmu_hpte_cache_next(vcpu);

  		trace_kvm_book3s_64_mmu_map(rflags, hpteg, va, hpaddr, orig_pte);

  		/* The ppc_md code may give us a secondary entry even though we
  		   asked for a primary. Fix up. */
  		if ((ret & _PTEIDX_SECONDARY) && !(vflags & HPTE_V_SECONDARY)) {
  			hash = ~hash;
  			hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
  		}

  		pte->slot = hpteg + (ret & 7);
  		pte->host_va = va;
  		pte->pte = *orig_pte;
  		pte->pfn = hpaddr >> PAGE_SHIFT;

  
  		kvmppc_mmu_hpte_cache_map(vcpu, pte);

  	}
  
  	return 0;
  }
  
  static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
  {
  	struct kvmppc_sid_map *map;
  	struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
  	u16 sid_map_mask;
  	static int backwards_map = 0;

  	if (vcpu->arch.shared->msr & MSR_PR)

  		gvsid |= VSID_PR;
  
  	/* We might get collisions that trap in preceding order, so let's
  	   map them differently */
  
  	sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
  	if (backwards_map)
  		sid_map_mask = SID_MAP_MASK - sid_map_mask;
  
  	map = &to_book3s(vcpu)->sid_map[sid_map_mask];
  
  	/* Make sure we're taking the other map next time */
  	backwards_map = !backwards_map;
  
  	/* Uh-oh ... out of mappings. Let's flush! */
  	if (vcpu_book3s->vsid_next == vcpu_book3s->vsid_max) {
  		vcpu_book3s->vsid_next = vcpu_book3s->vsid_first;
  		memset(vcpu_book3s->sid_map, 0,
  		       sizeof(struct kvmppc_sid_map) * SID_MAP_NUM);
  		kvmppc_mmu_pte_flush(vcpu, 0, 0);
  		kvmppc_mmu_flush_segments(vcpu);
  	}
  	map->host_vsid = vcpu_book3s->vsid_next++;
  
  	map->guest_vsid = gvsid;
  	map->valid = true;

  	trace_kvm_book3s_slb_map(sid_map_mask, gvsid, map->host_vsid);

  	return map;
  }
  
  static int kvmppc_mmu_next_segment(struct kvm_vcpu *vcpu, ulong esid)
  {
  	int i;
  	int max_slb_size = 64;
  	int found_inval = -1;
  	int r;

  	if (!to_svcpu(vcpu)->slb_max)
  		to_svcpu(vcpu)->slb_max = 1;

  
  	/* Are we overwriting? */

  	for (i = 1; i < to_svcpu(vcpu)->slb_max; i++) {
  		if (!(to_svcpu(vcpu)->slb[i].esid & SLB_ESID_V))

  			found_inval = i;

  		else if ((to_svcpu(vcpu)->slb[i].esid & ESID_MASK) == esid)

  			return i;
  	}
  
  	/* Found a spare entry that was invalidated before */
  	if (found_inval > 0)
  		return found_inval;
  
  	/* No spare invalid entry, so create one */
  
  	if (mmu_slb_size < 64)
  		max_slb_size = mmu_slb_size;
  
  	/* Overflowing -> purge */

  	if ((to_svcpu(vcpu)->slb_max) == max_slb_size)

  		kvmppc_mmu_flush_segments(vcpu);

  	r = to_svcpu(vcpu)->slb_max;
  	to_svcpu(vcpu)->slb_max++;

  
  	return r;
  }
  
  int kvmppc_mmu_map_segment(struct kvm_vcpu *vcpu, ulong eaddr)
  {
  	u64 esid = eaddr >> SID_SHIFT;
  	u64 slb_esid = (eaddr & ESID_MASK) | SLB_ESID_V;
  	u64 slb_vsid = SLB_VSID_USER;
  	u64 gvsid;
  	int slb_index;
  	struct kvmppc_sid_map *map;
  
  	slb_index = kvmppc_mmu_next_segment(vcpu, eaddr & ESID_MASK);
  
  	if (vcpu->arch.mmu.esid_to_vsid(vcpu, esid, &gvsid)) {
  		/* Invalidate an entry */

  		to_svcpu(vcpu)->slb[slb_index].esid = 0;

  		return -ENOENT;
  	}
  
  	map = find_sid_vsid(vcpu, gvsid);
  	if (!map)
  		map = create_sid_map(vcpu, gvsid);
  
  	map->guest_esid = esid;
  
  	slb_vsid |= (map->host_vsid << 12);
  	slb_vsid &= ~SLB_VSID_KP;
  	slb_esid |= slb_index;

  	to_svcpu(vcpu)->slb[slb_index].esid = slb_esid;
  	to_svcpu(vcpu)->slb[slb_index].vsid = slb_vsid;

  	trace_kvm_book3s_slbmte(slb_vsid, slb_esid);

  
  	return 0;
  }
  
  void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
  {

  	to_svcpu(vcpu)->slb_max = 1;
  	to_svcpu(vcpu)->slb[0].esid = 0;

  }
  
  void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
  {

  	kvmppc_mmu_hpte_destroy(vcpu);

  	__destroy_context(to_book3s(vcpu)->context_id[0]);

  }
  
  int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
  {
  	struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
  	int err;
  
  	err = __init_new_context();
  	if (err < 0)
  		return -1;

  	vcpu3s->context_id[0] = err;

  	vcpu3s->vsid_max = ((vcpu3s->context_id[0] + 1) << USER_ESID_BITS) - 1;
  	vcpu3s->vsid_first = vcpu3s->context_id[0] << USER_ESID_BITS;

  	vcpu3s->vsid_next = vcpu3s->vsid_first;

  	kvmppc_mmu_hpte_init(vcpu);

  	return 0;

  }