// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2009 SUSE Linux Products GmbH. All rights reserved.
 *
 * Authors:
 *     Alexander Graf <agraf@suse.de>
 *     Kevin Wolf <mail@kevin-wolf.de>
 */

#include <linux/kvm_host.h>
#include <linux/pkeys.h>

#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/book3s/64/mmu-hash.h>
#include <asm/machdep.h>
#include <asm/mmu_context.h>
#include <asm/hw_irq.h>
#include "trace_pr.h"
#include "book3s.h"

#define PTE_SIZE 12

void kvmppc_mmu_invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
{
        mmu_hash_ops.hpte_invalidate(pte->slot, pte->host_vpn,
                                     pte->pagesize, pte->pagesize,
                                     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 (kvmppc_get_msr(vcpu) & 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,
                        bool iswrite)
{
        unsigned long vpn;
        kvm_pfn_t hpaddr;
        ulong hash, hpteg;
        u64 vsid;
        int ret;
        int rflags = 0x192;
        int vflags = 0;
        int attempt = 0;
        struct kvmppc_sid_map *map;
        int r = 0;
        int hpsize = MMU_PAGE_4K;
        bool writable;
        unsigned long mmu_seq;
        struct kvm *kvm = vcpu->kvm;
        struct hpte_cache *cpte;
        unsigned long gfn = orig_pte->raddr >> PAGE_SHIFT;
        unsigned long pfn;
        struct page *page;

        /* used to check for invalidations in progress */
        mmu_seq = kvm->mmu_invalidate_seq;
        smp_rmb();

        /* Get host physical address for gpa */
        pfn = kvmppc_gpa_to_pfn(vcpu, orig_pte->raddr, iswrite, &writable, &page);
        if (is_error_noslot_pfn(pfn)) {
                printk(KERN_INFO "Couldn't get guest page for gpa %lx!\n",
                       orig_pte->raddr);
                r = -EINVAL;
                goto out;
        }
        hpaddr = pfn << PAGE_SHIFT;

        /* 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\n",
                                vsid, orig_pte->eaddr);
                WARN_ON(true);
                r = -EINVAL;
                goto out;
        }

        vpn = hpt_vpn(orig_pte->eaddr, map->host_vsid, MMU_SEGSIZE_256M);

        if (!orig_pte->may_write || !writable)
                rflags |= PP_RXRX;
        else
                mark_page_dirty(vcpu->kvm, gfn);

        if (!orig_pte->may_execute)
                rflags |= HPTE_R_N;
        else
                kvmppc_mmu_flush_icache(pfn);

        rflags |= pte_to_hpte_pkey_bits(0, HPTE_USE_KERNEL_KEY);
        rflags = (rflags & ~HPTE_R_WIMG) | orig_pte->wimg;

        /*
         * Use 64K pages if possible; otherwise, on 64K page kernels,
         * we need to transfer 4 more bits from guest real to host real addr.
         */
        if (vsid & VSID_64K)
                hpsize = MMU_PAGE_64K;
        else
                hpaddr |= orig_pte->raddr & (~0xfffULL & ~PAGE_MASK);

        hash = hpt_hash(vpn, mmu_psize_defs[hpsize].shift, MMU_SEGSIZE_256M);

        cpte = kvmppc_mmu_hpte_cache_next(vcpu);

        spin_lock(&kvm->mmu_lock);
        if (!cpte || mmu_invalidate_retry(kvm, mmu_seq)) {
                r = -EAGAIN;
                goto out_unlock;
        }

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 (mmu_hash_ops.hpte_remove(hpteg) < 0) {
                        r = -1;
                        goto out_unlock;
                }

        ret = mmu_hash_ops.hpte_insert(hpteg, vpn, hpaddr, rflags, vflags,
                                       hpsize, hpsize, MMU_SEGSIZE_256M);

        if (ret == -1) {
                /* If we couldn't map a primary PTE, try a secondary */
                hash = ~hash;
                vflags ^= HPTE_V_SECONDARY;
                attempt++;
                goto map_again;
        } else if (ret < 0) {
                r = -EIO;
                goto out_unlock;
        } else {
                trace_kvm_book3s_64_mmu_map(rflags, hpteg,
                                            vpn, hpaddr, orig_pte);

                /*
                 * The mmu_hash_ops 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);
                }

                cpte->slot = hpteg + (ret & 7);
                cpte->host_vpn = vpn;
                cpte->pte = *orig_pte;
                cpte->pfn = pfn;
                cpte->pagesize = hpsize;

                kvmppc_mmu_hpte_cache_map(vcpu, cpte);
                cpte = NULL;
        }

out_unlock:
        /* FIXME: Don't unconditionally pass unused=false. */
        kvm_release_faultin_page(kvm, page, false,
                                 orig_pte->may_write && writable);
        spin_unlock(&kvm->mmu_lock);
        if (cpte)
                kvmppc_mmu_hpte_cache_free(cpte);

out:
        return r;
}

void kvmppc_mmu_unmap_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)
{
        u64 mask = 0xfffffffffULL;
        u64 vsid;

        vcpu->arch.mmu.esid_to_vsid(vcpu, pte->eaddr >> SID_SHIFT, &vsid);
        if (vsid & VSID_64K)
                mask = 0xffffffff0ULL;
        kvmppc_mmu_pte_vflush(vcpu, pte->vpage, mask);
}

static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
{
        unsigned long vsid_bits = VSID_BITS_65_256M;
        struct kvmppc_sid_map *map;
        struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
        u16 sid_map_mask;
        static int backwards_map;

        if (kvmppc_get_msr(vcpu) & 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->proto_vsid_next == vcpu_book3s->proto_vsid_max) {
                vcpu_book3s->proto_vsid_next = vcpu_book3s->proto_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);
        }

        if (mmu_has_feature(MMU_FTR_68_BIT_VA))
                vsid_bits = VSID_BITS_256M;

        map->host_vsid = vsid_scramble(vcpu_book3s->proto_vsid_next++,
                                       VSID_MULTIPLIER_256M, vsid_bits);

        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)
{
        struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
        int i;
        int max_slb_size = 64;
        int found_inval = -1;
        int r;

        /* Are we overwriting? */
        for (i = 0; i < svcpu->slb_max; i++) {
                if (!(svcpu->slb[i].esid & SLB_ESID_V))
                        found_inval = i;
                else if ((svcpu->slb[i].esid & ESID_MASK) == esid) {
                        r = i;
                        goto out;
                }
        }

        /* Found a spare entry that was invalidated before */
        if (found_inval >= 0) {
                r = found_inval;
                goto out;
        }

        /* No spare invalid entry, so create one */

        if (mmu_slb_size < 64)
                max_slb_size = mmu_slb_size;

        /* Overflowing -> purge */
        if ((svcpu->slb_max) == max_slb_size)
                kvmppc_mmu_flush_segments(vcpu);

        r = svcpu->slb_max;
        svcpu->slb_max++;

out:
        svcpu_put(svcpu);
        return r;
}

int kvmppc_mmu_map_segment(struct kvm_vcpu *vcpu, ulong eaddr)
{
        struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
        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;
        int r = 0;

        slb_index = kvmppc_mmu_next_segment(vcpu, eaddr & ESID_MASK);

        if (vcpu->arch.mmu.esid_to_vsid(vcpu, esid, &gvsid)) {
                /* Invalidate an entry */
                svcpu->slb[slb_index].esid = 0;
                r = -ENOENT;
                goto out;
        }

        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;

#ifdef CONFIG_PPC_64K_PAGES
        /* Set host segment base page size to 64K if possible */
        if (gvsid & VSID_64K)
                slb_vsid |= mmu_psize_defs[MMU_PAGE_64K].sllp;
#endif

        svcpu->slb[slb_index].esid = slb_esid;
        svcpu->slb[slb_index].vsid = slb_vsid;

        trace_kvm_book3s_slbmte(slb_vsid, slb_esid);

out:
        svcpu_put(svcpu);
        return r;
}

void kvmppc_mmu_flush_segment(struct kvm_vcpu *vcpu, ulong ea, ulong seg_size)
{
        struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
        ulong seg_mask = -seg_size;
        int i;

        for (i = 0; i < svcpu->slb_max; i++) {
                if ((svcpu->slb[i].esid & SLB_ESID_V) &&
                    (svcpu->slb[i].esid & seg_mask) == ea) {
                        /* Invalidate this entry */
                        svcpu->slb[i].esid = 0;
                }
        }

        svcpu_put(svcpu);
}

void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
{
        struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
        svcpu->slb_max = 0;
        svcpu->slb[0].esid = 0;
        svcpu_put(svcpu);
}

void kvmppc_mmu_destroy_pr(struct kvm_vcpu *vcpu)
{
        kvmppc_mmu_hpte_destroy(vcpu);
        __destroy_context(to_book3s(vcpu)->context_id[0]);
}

int kvmppc_mmu_init_pr(struct kvm_vcpu *vcpu)
{
        struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
        int err;

        err = hash__alloc_context_id();
        if (err < 0)
                return -1;
        vcpu3s->context_id[0] = err;

        vcpu3s->proto_vsid_max = ((u64)(vcpu3s->context_id[0] + 1)
                                  << ESID_BITS) - 1;
        vcpu3s->proto_vsid_first = (u64)vcpu3s->context_id[0] << ESID_BITS;
        vcpu3s->proto_vsid_next = vcpu3s->proto_vsid_first;

        kvmppc_mmu_hpte_init(vcpu);

        return 0;
}