book3s_64_mmu_host.c

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/*
 * Copyright (C) 2009 SUSE Linux Products GmbH. All rights reserved.
 *
 * Authors:
 *     Alexander Graf <[email protected]>
 *     Kevin Wolf <[email protected]>
 *
 * 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_vpn,
                   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)
{
    unsigned long vpn;
    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;

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

    vsid = map->host_vsid;
    vpn = hpt_vpn(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;
    else
        kvmppc_mmu_flush_icache(hpaddr >> PAGE_SHIFT);

    hash = hpt_hash(vpn, 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) {
            r = -1;
            goto out;
        }

    ret = ppc_md.hpte_insert(hpteg, vpn, 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,
                        vpn, 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_vpn = vpn;
        pte->pte = *orig_pte;
        pte->pfn = hpaddr >> PAGE_SHIFT;

        kvmppc_mmu_hpte_cache_map(vcpu, pte);
    }

out:
    return r;
}

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->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);
    }
    map->host_vsid = vsid_scramble(vcpu_book3s->proto_vsid_next++, 256M);

    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;

    if (!svcpu->slb_max)
        svcpu->slb_max = 1;

    /* Are we overwriting? */
    for (i = 1; 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;

    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_segments(struct kvm_vcpu *vcpu)
{
    struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
    svcpu->slb_max = 1;
    svcpu->slb[0].esid = 0;
    svcpu_put(svcpu);
}

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

    kvmppc_mmu_hpte_init(vcpu);

    return 0;
}