/*
 * 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.
 *
 * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>

#include <asm/tlbflush.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/mmu-hash64.h>
#include <asm/hvcall.h>
#include <asm/synch.h>
#include <asm/ppc-opcode.h>
#include <asm/cputable.h>

/* For now use fixed-size 16MB page table */
#define HPT_ORDER       24
#define HPT_NPTEG       (1ul << (HPT_ORDER - 7))        /* 128B per pteg */
#define HPT_HASH_MASK   (HPT_NPTEG - 1)

/* Pages in the VRMA are 16MB pages */
#define VRMA_PAGE_ORDER 24
#define VRMA_VSID       0x1ffffffUL     /* 1TB VSID reserved for VRMA */

/* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */
#define MAX_LPID_970    63
#define NR_LPIDS        (LPID_RSVD + 1)
unsigned long lpid_inuse[BITS_TO_LONGS(NR_LPIDS)];

long kvmppc_alloc_hpt(struct kvm *kvm)
{
        unsigned long hpt;
        unsigned long lpid;

        hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|__GFP_NOWARN,
                               HPT_ORDER - PAGE_SHIFT);
        if (!hpt) {
                pr_err("kvm_alloc_hpt: Couldn't alloc HPT\n");
                return -ENOMEM;
        }
        kvm->arch.hpt_virt = hpt;

        do {
                lpid = find_first_zero_bit(lpid_inuse, NR_LPIDS);
                if (lpid >= NR_LPIDS) {
                        pr_err("kvm_alloc_hpt: No LPIDs free\n");
                        free_pages(hpt, HPT_ORDER - PAGE_SHIFT);
                        return -ENOMEM;
                }
        } while (test_and_set_bit(lpid, lpid_inuse));

        kvm->arch.sdr1 = __pa(hpt) | (HPT_ORDER - 18);
        kvm->arch.lpid = lpid;

        pr_info("KVM guest htab at %lx, LPID %lx\n", hpt, lpid);
        return 0;
}

void kvmppc_free_hpt(struct kvm *kvm)
{
        clear_bit(kvm->arch.lpid, lpid_inuse);
        free_pages(kvm->arch.hpt_virt, HPT_ORDER - PAGE_SHIFT);
}

void kvmppc_map_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem)
{
        unsigned long i;
        unsigned long npages = kvm->arch.ram_npages;
        unsigned long pfn;
        unsigned long *hpte;
        unsigned long hash;
        struct kvmppc_pginfo *pginfo = kvm->arch.ram_pginfo;

        if (!pginfo)
                return;

        /* VRMA can't be > 1TB */
        if (npages > 1ul << (40 - kvm->arch.ram_porder))
                npages = 1ul << (40 - kvm->arch.ram_porder);
        /* Can't use more than 1 HPTE per HPTEG */
        if (npages > HPT_NPTEG)
                npages = HPT_NPTEG;

        for (i = 0; i < npages; ++i) {
                pfn = pginfo[i].pfn;
                if (!pfn)
                        break;
                /* can't use hpt_hash since va > 64 bits */
                hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25))) & HPT_HASH_MASK;
                /*
                 * We assume that the hash table is empty and no
                 * vcpus are using it at this stage.  Since we create
                 * at most one HPTE per HPTEG, we just assume entry 7
                 * is available and use it.
                 */
                hpte = (unsigned long *) (kvm->arch.hpt_virt + (hash << 7));
                hpte += 7 * 2;
                /* HPTE low word - RPN, protection, etc. */
                hpte[1] = (pfn << PAGE_SHIFT) | HPTE_R_R | HPTE_R_C |
                        HPTE_R_M | PP_RWXX;
                wmb();
                hpte[0] = HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)) |
                        (i << (VRMA_PAGE_ORDER - 16)) | HPTE_V_BOLTED |
                        HPTE_V_LARGE | HPTE_V_VALID;
        }
}

int kvmppc_mmu_hv_init(void)
{
        unsigned long host_lpid, rsvd_lpid;

        if (!cpu_has_feature(CPU_FTR_HVMODE))
                return -EINVAL;

        memset(lpid_inuse, 0, sizeof(lpid_inuse));

        if (cpu_has_feature(CPU_FTR_ARCH_206)) {
                host_lpid = mfspr(SPRN_LPID);   /* POWER7 */
                rsvd_lpid = LPID_RSVD;
        } else {
                host_lpid = 0;                  /* PPC970 */
                rsvd_lpid = MAX_LPID_970;
        }

        set_bit(host_lpid, lpid_inuse);
        /* rsvd_lpid is reserved for use in partition switching */
        set_bit(rsvd_lpid, lpid_inuse);

        return 0;
}

void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
{
}

static void kvmppc_mmu_book3s_64_hv_reset_msr(struct kvm_vcpu *vcpu)
{
        kvmppc_set_msr(vcpu, MSR_SF | MSR_ME);
}

static int kvmppc_mmu_book3s_64_hv_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
                                struct kvmppc_pte *gpte, bool data)
{
        return -ENOENT;
}

void kvmppc_mmu_book3s_hv_init(struct kvm_vcpu *vcpu)
{
        struct kvmppc_mmu *mmu = &vcpu->arch.mmu;

        if (cpu_has_feature(CPU_FTR_ARCH_206))
                vcpu->arch.slb_nr = 32;         /* POWER7 */
        else
                vcpu->arch.slb_nr = 64;

        mmu->xlate = kvmppc_mmu_book3s_64_hv_xlate;
        mmu->reset_msr = kvmppc_mmu_book3s_64_hv_reset_msr;

        vcpu->arch.hflags |= BOOK3S_HFLAG_SLB;
}