root/arch/powerpc/kvm/book3s_32_mmu.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright SUSE Linux Products GmbH 2009
 *
 * Authors: Alexander Graf <agraf@suse.de>
 */

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

#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>

/* #define DEBUG_MMU */
/* #define DEBUG_MMU_PTE */
/* #define DEBUG_MMU_PTE_IP 0xfff14c40 */

#ifdef DEBUG_MMU
#define dprintk(X...) printk(KERN_INFO X)
#else
#define dprintk(X...) do { } while(0)
#endif

#ifdef DEBUG_MMU_PTE
#define dprintk_pte(X...) printk(KERN_INFO X)
#else
#define dprintk_pte(X...) do { } while(0)
#endif

#define PTEG_FLAG_ACCESSED      0x00000100
#define PTEG_FLAG_DIRTY         0x00000080
#ifndef SID_SHIFT
#define SID_SHIFT               28
#endif

static inline bool check_debug_ip(struct kvm_vcpu *vcpu)
{
#ifdef DEBUG_MMU_PTE_IP
        return vcpu->arch.regs.nip == DEBUG_MMU_PTE_IP;
#else
        return true;
#endif
}

static inline u32 sr_vsid(u32 sr_raw)
{
        return sr_raw & 0x0fffffff;
}

static inline bool sr_valid(u32 sr_raw)
{
        return (sr_raw & 0x80000000) ? false : true;
}

static inline bool sr_ks(u32 sr_raw)
{
        return (sr_raw & 0x40000000) ? true: false;
}

static inline bool sr_kp(u32 sr_raw)
{
        return (sr_raw & 0x20000000) ? true: false;
}

static int kvmppc_mmu_book3s_32_xlate_bat(struct kvm_vcpu *vcpu, gva_t eaddr,
                                          struct kvmppc_pte *pte, bool data,
                                          bool iswrite);
static int kvmppc_mmu_book3s_32_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
                                             u64 *vsid);

static u32 find_sr(struct kvm_vcpu *vcpu, gva_t eaddr)
{
        return kvmppc_get_sr(vcpu, (eaddr >> 28) & 0xf);
}

static u64 kvmppc_mmu_book3s_32_ea_to_vp(struct kvm_vcpu *vcpu, gva_t eaddr,
                                         bool data)
{
        u64 vsid;
        struct kvmppc_pte pte;

        if (!kvmppc_mmu_book3s_32_xlate_bat(vcpu, eaddr, &pte, data, false))
                return pte.vpage;

        kvmppc_mmu_book3s_32_esid_to_vsid(vcpu, eaddr >> SID_SHIFT, &vsid);
        return (((u64)eaddr >> 12) & 0xffff) | (vsid << 16);
}

static hva_t kvmppc_mmu_book3s_32_get_pteg(struct kvm_vcpu *vcpu,
                                      u32 sre, gva_t eaddr,
                                      bool primary)
{
        struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
        u32 page, hash, pteg, htabmask;
        hva_t r;

        page = (eaddr & 0x0FFFFFFF) >> 12;
        htabmask = ((vcpu_book3s->sdr1 & 0x1FF) << 16) | 0xFFC0;

        hash = ((sr_vsid(sre) ^ page) << 6);
        if (!primary)
                hash = ~hash;
        hash &= htabmask;

        pteg = (vcpu_book3s->sdr1 & 0xffff0000) | hash;

        dprintk("MMU: pc=0x%lx eaddr=0x%lx sdr1=0x%llx pteg=0x%x vsid=0x%x\n",
                kvmppc_get_pc(vcpu), eaddr, vcpu_book3s->sdr1, pteg,
                sr_vsid(sre));

        r = gfn_to_hva(vcpu->kvm, pteg >> PAGE_SHIFT);
        if (kvm_is_error_hva(r))
                return r;
        return r | (pteg & ~PAGE_MASK);
}

static u32 kvmppc_mmu_book3s_32_get_ptem(u32 sre, gva_t eaddr, bool primary)
{
        return ((eaddr & 0x0fffffff) >> 22) | (sr_vsid(sre) << 7) |
               (primary ? 0 : 0x40) | 0x80000000;
}

static int kvmppc_mmu_book3s_32_xlate_bat(struct kvm_vcpu *vcpu, gva_t eaddr,
                                          struct kvmppc_pte *pte, bool data,
                                          bool iswrite)
{
        struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
        struct kvmppc_bat *bat;
        int i;

        for (i = 0; i < 8; i++) {
                if (data)
                        bat = &vcpu_book3s->dbat[i];
                else
                        bat = &vcpu_book3s->ibat[i];

                if (kvmppc_get_msr(vcpu) & MSR_PR) {
                        if (!bat->vp)
                                continue;
                } else {
                        if (!bat->vs)
                                continue;
                }

                if (check_debug_ip(vcpu))
                {
                        dprintk_pte("%cBAT %02d: 0x%lx - 0x%x (0x%x)\n",
                                    data ? 'd' : 'i', i, eaddr, bat->bepi,
                                    bat->bepi_mask);
                }
                if ((eaddr & bat->bepi_mask) == bat->bepi) {
                        u64 vsid;
                        kvmppc_mmu_book3s_32_esid_to_vsid(vcpu,
                                eaddr >> SID_SHIFT, &vsid);
                        vsid <<= 16;
                        pte->vpage = (((u64)eaddr >> 12) & 0xffff) | vsid;

                        pte->raddr = bat->brpn | (eaddr & ~bat->bepi_mask);
                        pte->may_read = bat->pp;
                        pte->may_write = bat->pp > 1;
                        pte->may_execute = true;
                        if (!pte->may_read) {
                                printk(KERN_INFO "BAT is not readable!\n");
                                continue;
                        }
                        if (iswrite && !pte->may_write) {
                                dprintk_pte("BAT is read-only!\n");
                                continue;
                        }

                        return 0;
                }
        }

        return -ENOENT;
}

static int kvmppc_mmu_book3s_32_xlate_pte(struct kvm_vcpu *vcpu, gva_t eaddr,
                                     struct kvmppc_pte *pte, bool data,
                                     bool iswrite, bool primary)
{
        u32 sre;
        hva_t ptegp;
        u32 pteg[16];
        u32 pte0, pte1;
        u32 ptem = 0;
        int i;
        int found = 0;

        sre = find_sr(vcpu, eaddr);

        dprintk_pte("SR 0x%lx: vsid=0x%x, raw=0x%x\n", eaddr >> 28,
                    sr_vsid(sre), sre);

        pte->vpage = kvmppc_mmu_book3s_32_ea_to_vp(vcpu, eaddr, data);

        ptegp = kvmppc_mmu_book3s_32_get_pteg(vcpu, sre, eaddr, primary);
        if (kvm_is_error_hva(ptegp)) {
                printk(KERN_INFO "KVM: Invalid PTEG!\n");
                goto no_page_found;
        }

        ptem = kvmppc_mmu_book3s_32_get_ptem(sre, eaddr, primary);

        if(copy_from_user(pteg, (void __user *)ptegp, sizeof(pteg))) {
                printk_ratelimited(KERN_ERR
                        "KVM: Can't copy data from 0x%lx!\n", ptegp);
                goto no_page_found;
        }

        for (i=0; i<16; i+=2) {
                pte0 = be32_to_cpu(pteg[i]);
                pte1 = be32_to_cpu(pteg[i + 1]);
                if (ptem == pte0) {
                        u8 pp;

                        pte->raddr = (pte1 & ~(0xFFFULL)) | (eaddr & 0xFFF);
                        pp = pte1 & 3;

                        if ((sr_kp(sre) &&  (kvmppc_get_msr(vcpu) & MSR_PR)) ||
                            (sr_ks(sre) && !(kvmppc_get_msr(vcpu) & MSR_PR)))
                                pp |= 4;

                        pte->may_write = false;
                        pte->may_read = false;
                        pte->may_execute = true;
                        switch (pp) {
                                case 0:
                                case 1:
                                case 2:
                                case 6:
                                        pte->may_write = true;
                                        fallthrough;
                                case 3:
                                case 5:
                                case 7:
                                        pte->may_read = true;
                                        break;
                        }

                        dprintk_pte("MMU: Found PTE -> %x %x - %x\n",
                                    pte0, pte1, pp);
                        found = 1;
                        break;
                }
        }

        /* Update PTE C and A bits, so the guest's swapper knows we used the
           page */
        if (found) {
                u32 pte_r = pte1;
                char __user *addr = (char __user *) (ptegp + (i+1) * sizeof(u32));

                /*
                 * Use single-byte writes to update the HPTE, to
                 * conform to what real hardware does.
                 */
                if (pte->may_read && !(pte_r & PTEG_FLAG_ACCESSED)) {
                        pte_r |= PTEG_FLAG_ACCESSED;
                        put_user(pte_r >> 8, addr + 2);
                }
                if (iswrite && pte->may_write && !(pte_r & PTEG_FLAG_DIRTY)) {
                        pte_r |= PTEG_FLAG_DIRTY;
                        put_user(pte_r, addr + 3);
                }
                if (!pte->may_read || (iswrite && !pte->may_write))
                        return -EPERM;
                return 0;
        }

no_page_found:

        if (check_debug_ip(vcpu)) {
                dprintk_pte("KVM MMU: No PTE found (sdr1=0x%llx ptegp=0x%lx)\n",
                            to_book3s(vcpu)->sdr1, ptegp);
                for (i=0; i<16; i+=2) {
                        dprintk_pte("   %02d: 0x%x - 0x%x (0x%x)\n",
                                    i, be32_to_cpu(pteg[i]),
                                    be32_to_cpu(pteg[i+1]), ptem);
                }
        }

        return -ENOENT;
}

static int kvmppc_mmu_book3s_32_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
                                      struct kvmppc_pte *pte, bool data,
                                      bool iswrite)
{
        int r;
        ulong mp_ea = vcpu->arch.magic_page_ea;

        pte->eaddr = eaddr;
        pte->page_size = MMU_PAGE_4K;

        /* Magic page override */
        if (unlikely(mp_ea) &&
            unlikely((eaddr & ~0xfffULL) == (mp_ea & ~0xfffULL)) &&
            !(kvmppc_get_msr(vcpu) & MSR_PR)) {
                pte->vpage = kvmppc_mmu_book3s_32_ea_to_vp(vcpu, eaddr, data);
                pte->raddr = vcpu->arch.magic_page_pa | (pte->raddr & 0xfff);
                pte->raddr &= KVM_PAM;
                pte->may_execute = true;
                pte->may_read = true;
                pte->may_write = true;

                return 0;
        }

        r = kvmppc_mmu_book3s_32_xlate_bat(vcpu, eaddr, pte, data, iswrite);
        if (r < 0)
                r = kvmppc_mmu_book3s_32_xlate_pte(vcpu, eaddr, pte,
                                                   data, iswrite, true);
        if (r == -ENOENT)
                r = kvmppc_mmu_book3s_32_xlate_pte(vcpu, eaddr, pte,
                                                   data, iswrite, false);

        return r;
}


static u32 kvmppc_mmu_book3s_32_mfsrin(struct kvm_vcpu *vcpu, u32 srnum)
{
        return kvmppc_get_sr(vcpu, srnum);
}

static void kvmppc_mmu_book3s_32_mtsrin(struct kvm_vcpu *vcpu, u32 srnum,
                                        ulong value)
{
        kvmppc_set_sr(vcpu, srnum, value);
        kvmppc_mmu_map_segment(vcpu, srnum << SID_SHIFT);
}

static void kvmppc_mmu_book3s_32_tlbie(struct kvm_vcpu *vcpu, ulong ea, bool large)
{
        unsigned long i;
        struct kvm_vcpu *v;

        /* flush this VA on all cpus */
        kvm_for_each_vcpu(i, v, vcpu->kvm)
                kvmppc_mmu_pte_flush(v, ea, 0x0FFFF000);
}

static int kvmppc_mmu_book3s_32_esid_to_vsid(struct kvm_vcpu *vcpu, ulong esid,
                                             u64 *vsid)
{
        ulong ea = esid << SID_SHIFT;
        u32 sr;
        u64 gvsid = esid;
        u64 msr = kvmppc_get_msr(vcpu);

        if (msr & (MSR_DR|MSR_IR)) {
                sr = find_sr(vcpu, ea);
                if (sr_valid(sr))
                        gvsid = sr_vsid(sr);
        }

        /* In case we only have one of MSR_IR or MSR_DR set, let's put
           that in the real-mode context (and hope RM doesn't access
           high memory) */
        switch (msr & (MSR_DR|MSR_IR)) {
        case 0:
                *vsid = VSID_REAL | esid;
                break;
        case MSR_IR:
                *vsid = VSID_REAL_IR | gvsid;
                break;
        case MSR_DR:
                *vsid = VSID_REAL_DR | gvsid;
                break;
        case MSR_DR|MSR_IR:
                if (sr_valid(sr))
                        *vsid = sr_vsid(sr);
                else
                        *vsid = VSID_BAT | gvsid;
                break;
        default:
                BUG();
        }

        if (msr & MSR_PR)
                *vsid |= VSID_PR;

        return 0;
}

static bool kvmppc_mmu_book3s_32_is_dcbz32(struct kvm_vcpu *vcpu)
{
        return true;
}


void kvmppc_mmu_book3s_32_init(struct kvm_vcpu *vcpu)
{
        struct kvmppc_mmu *mmu = &vcpu->arch.mmu;

        mmu->mtsrin = kvmppc_mmu_book3s_32_mtsrin;
        mmu->mfsrin = kvmppc_mmu_book3s_32_mfsrin;
        mmu->xlate = kvmppc_mmu_book3s_32_xlate;
        mmu->tlbie = kvmppc_mmu_book3s_32_tlbie;
        mmu->esid_to_vsid = kvmppc_mmu_book3s_32_esid_to_vsid;
        mmu->ea_to_vp = kvmppc_mmu_book3s_32_ea_to_vp;
        mmu->is_dcbz32 = kvmppc_mmu_book3s_32_is_dcbz32;

        mmu->slbmte = NULL;
        mmu->slbmfee = NULL;
        mmu->slbmfev = NULL;
        mmu->slbfee = NULL;
        mmu->slbie = NULL;
        mmu->slbia = NULL;
}