[~andy/linux] / arch / powerpc / kvm / book3s_hv.c

/*
 * Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
 * Copyright (C) 2009. SUSE Linux Products GmbH. All rights reserved.
 *
 * Authors:
 *    Paul Mackerras <paulus@au1.ibm.com>
 *    Alexander Graf <agraf@suse.de>
 *    Kevin Wolf <mail@kevin-wolf.de>
 *
 * Description: KVM functions specific to running on Book 3S
 * processors in hypervisor mode (specifically POWER7 and later).
 *
 * This file is derived from arch/powerpc/kvm/book3s.c,
 * by Alexander Graf <agraf@suse.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.
 */

#include <linux/kvm_host.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/anon_inodes.h>
#include <linux/cpumask.h>
#include <linux/spinlock.h>
#include <linux/page-flags.h>
#include <linux/srcu.h>

#include <asm/reg.h>
#include <asm/cputable.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/mmu_context.h>
#include <asm/lppaca.h>
#include <asm/processor.h>
#include <asm/cputhreads.h>
#include <asm/page.h>
#include <asm/hvcall.h>
#include <asm/switch_to.h>
#include <asm/smp.h>
#include <linux/gfp.h>
#include <linux/vmalloc.h>
#include <linux/highmem.h>
#include <linux/hugetlb.h>

/* #define EXIT_DEBUG */
/* #define EXIT_DEBUG_SIMPLE */
/* #define EXIT_DEBUG_INT */

/* Used to indicate that a guest page fault needs to be handled */
#define RESUME_PAGE_FAULT       (RESUME_GUEST | RESUME_FLAG_ARCH1)

/* Used as a "null" value for timebase values */
#define TB_NIL  (~(u64)0)

static void kvmppc_end_cede(struct kvm_vcpu *vcpu);
static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu);

void kvmppc_fast_vcpu_kick(struct kvm_vcpu *vcpu)
{
        int me;
        int cpu = vcpu->cpu;
        wait_queue_head_t *wqp;

        wqp = kvm_arch_vcpu_wq(vcpu);
        if (waitqueue_active(wqp)) {
                wake_up_interruptible(wqp);
                ++vcpu->stat.halt_wakeup;
        }

        me = get_cpu();

        /* CPU points to the first thread of the core */
        if (cpu != me && cpu >= 0 && cpu < nr_cpu_ids) {
                int real_cpu = cpu + vcpu->arch.ptid;
                if (paca[real_cpu].kvm_hstate.xics_phys)
                        xics_wake_cpu(real_cpu);
                else if (cpu_online(cpu))
                        smp_send_reschedule(cpu);
        }
        put_cpu();
}

/*
 * We use the vcpu_load/put functions to measure stolen time.
 * Stolen time is counted as time when either the vcpu is able to
 * run as part of a virtual core, but the task running the vcore
 * is preempted or sleeping, or when the vcpu needs something done
 * in the kernel by the task running the vcpu, but that task is
 * preempted or sleeping.  Those two things have to be counted
 * separately, since one of the vcpu tasks will take on the job
 * of running the core, and the other vcpu tasks in the vcore will
 * sleep waiting for it to do that, but that sleep shouldn't count
 * as stolen time.
 *
 * Hence we accumulate stolen time when the vcpu can run as part of
 * a vcore using vc->stolen_tb, and the stolen time when the vcpu
 * needs its task to do other things in the kernel (for example,
 * service a page fault) in busy_stolen.  We don't accumulate
 * stolen time for a vcore when it is inactive, or for a vcpu
 * when it is in state RUNNING or NOTREADY.  NOTREADY is a bit of
 * a misnomer; it means that the vcpu task is not executing in
 * the KVM_VCPU_RUN ioctl, i.e. it is in userspace or elsewhere in
 * the kernel.  We don't have any way of dividing up that time
 * between time that the vcpu is genuinely stopped, time that
 * the task is actively working on behalf of the vcpu, and time
 * that the task is preempted, so we don't count any of it as
 * stolen.
 *
 * Updates to busy_stolen are protected by arch.tbacct_lock;
 * updates to vc->stolen_tb are protected by the arch.tbacct_lock
 * of the vcpu that has taken responsibility for running the vcore
 * (i.e. vc->runner).  The stolen times are measured in units of
 * timebase ticks.  (Note that the != TB_NIL checks below are
 * purely defensive; they should never fail.)
 */

void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
        struct kvmppc_vcore *vc = vcpu->arch.vcore;

        spin_lock(&vcpu->arch.tbacct_lock);
        if (vc->runner == vcpu && vc->vcore_state != VCORE_INACTIVE &&
            vc->preempt_tb != TB_NIL) {
                vc->stolen_tb += mftb() - vc->preempt_tb;
                vc->preempt_tb = TB_NIL;
        }
        if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST &&
            vcpu->arch.busy_preempt != TB_NIL) {
                vcpu->arch.busy_stolen += mftb() - vcpu->arch.busy_preempt;
                vcpu->arch.busy_preempt = TB_NIL;
        }
        spin_unlock(&vcpu->arch.tbacct_lock);
}

void kvmppc_core_vcpu_put(struct kvm_vcpu *vcpu)
{
        struct kvmppc_vcore *vc = vcpu->arch.vcore;

        spin_lock(&vcpu->arch.tbacct_lock);
        if (vc->runner == vcpu && vc->vcore_state != VCORE_INACTIVE)
                vc->preempt_tb = mftb();
        if (vcpu->arch.state == KVMPPC_VCPU_BUSY_IN_HOST)
                vcpu->arch.busy_preempt = mftb();
        spin_unlock(&vcpu->arch.tbacct_lock);
}

void kvmppc_set_msr(struct kvm_vcpu *vcpu, u64 msr)
{
        vcpu->arch.shregs.msr = msr;
        kvmppc_end_cede(vcpu);
}

void kvmppc_set_pvr(struct kvm_vcpu *vcpu, u32 pvr)
{
        vcpu->arch.pvr = pvr;
}

void kvmppc_dump_regs(struct kvm_vcpu *vcpu)
{
        int r;

        pr_err("vcpu %p (%d):\n", vcpu, vcpu->vcpu_id);
        pr_err("pc  = %.16lx  msr = %.16llx  trap = %x\n",
               vcpu->arch.pc, vcpu->arch.shregs.msr, vcpu->arch.trap);
        for (r = 0; r < 16; ++r)
                pr_err("r%2d = %.16lx  r%d = %.16lx\n",
                       r, kvmppc_get_gpr(vcpu, r),
                       r+16, kvmppc_get_gpr(vcpu, r+16));
        pr_err("ctr = %.16lx  lr  = %.16lx\n",
               vcpu->arch.ctr, vcpu->arch.lr);
        pr_err("srr0 = %.16llx srr1 = %.16llx\n",
               vcpu->arch.shregs.srr0, vcpu->arch.shregs.srr1);
        pr_err("sprg0 = %.16llx sprg1 = %.16llx\n",
               vcpu->arch.shregs.sprg0, vcpu->arch.shregs.sprg1);
        pr_err("sprg2 = %.16llx sprg3 = %.16llx\n",
               vcpu->arch.shregs.sprg2, vcpu->arch.shregs.sprg3);
        pr_err("cr = %.8x  xer = %.16lx  dsisr = %.8x\n",
               vcpu->arch.cr, vcpu->arch.xer, vcpu->arch.shregs.dsisr);
        pr_err("dar = %.16llx\n", vcpu->arch.shregs.dar);
        pr_err("fault dar = %.16lx dsisr = %.8x\n",
               vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
        pr_err("SLB (%d entries):\n", vcpu->arch.slb_max);
        for (r = 0; r < vcpu->arch.slb_max; ++r)
                pr_err("  ESID = %.16llx VSID = %.16llx\n",
                       vcpu->arch.slb[r].orige, vcpu->arch.slb[r].origv);
        pr_err("lpcr = %.16lx sdr1 = %.16lx last_inst = %.8x\n",
               vcpu->kvm->arch.lpcr, vcpu->kvm->arch.sdr1,
               vcpu->arch.last_inst);
}

struct kvm_vcpu *kvmppc_find_vcpu(struct kvm *kvm, int id)
{
        int r;
        struct kvm_vcpu *v, *ret = NULL;

        mutex_lock(&kvm->lock);
        kvm_for_each_vcpu(r, v, kvm) {
                if (v->vcpu_id == id) {
                        ret = v;
                        break;
                }
        }
        mutex_unlock(&kvm->lock);
        return ret;
}

static void init_vpa(struct kvm_vcpu *vcpu, struct lppaca *vpa)
{
        vpa->shared_proc = 1;
        vpa->yield_count = 1;
}

static int set_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *v,
                   unsigned long addr, unsigned long len)
{
        /* check address is cacheline aligned */
        if (addr & (L1_CACHE_BYTES - 1))
                return -EINVAL;
        spin_lock(&vcpu->arch.vpa_update_lock);
        if (v->next_gpa != addr || v->len != len) {
                v->next_gpa = addr;
                v->len = addr ? len : 0;
                v->update_pending = 1;
        }
        spin_unlock(&vcpu->arch.vpa_update_lock);
        return 0;
}

/* Length for a per-processor buffer is passed in at offset 4 in the buffer */
struct reg_vpa {
        u32 dummy;
        union {
                u16 hword;
                u32 word;
        } length;
};

static int vpa_is_registered(struct kvmppc_vpa *vpap)
{
        if (vpap->update_pending)
                return vpap->next_gpa != 0;
        return vpap->pinned_addr != NULL;
}

static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
                                       unsigned long flags,
                                       unsigned long vcpuid, unsigned long vpa)
{
        struct kvm *kvm = vcpu->kvm;
        unsigned long len, nb;
        void *va;
        struct kvm_vcpu *tvcpu;
        int err;
        int subfunc;
        struct kvmppc_vpa *vpap;

        tvcpu = kvmppc_find_vcpu(kvm, vcpuid);
        if (!tvcpu)
                return H_PARAMETER;

        subfunc = (flags >> H_VPA_FUNC_SHIFT) & H_VPA_FUNC_MASK;
        if (subfunc == H_VPA_REG_VPA || subfunc == H_VPA_REG_DTL ||
            subfunc == H_VPA_REG_SLB) {
                /* Registering new area - address must be cache-line aligned */
                if ((vpa & (L1_CACHE_BYTES - 1)) || !vpa)
                        return H_PARAMETER;

                /* convert logical addr to kernel addr and read length */
                va = kvmppc_pin_guest_page(kvm, vpa, &nb);
                if (va == NULL)
                        return H_PARAMETER;
                if (subfunc == H_VPA_REG_VPA)
                        len = ((struct reg_vpa *)va)->length.hword;
                else
                        len = ((struct reg_vpa *)va)->length.word;
                kvmppc_unpin_guest_page(kvm, va, vpa, false);

                /* Check length */
                if (len > nb || len < sizeof(struct reg_vpa))
                        return H_PARAMETER;
        } else {
                vpa = 0;
                len = 0;
        }

        err = H_PARAMETER;
        vpap = NULL;
        spin_lock(&tvcpu->arch.vpa_update_lock);

        switch (subfunc) {
        case H_VPA_REG_VPA:             /* register VPA */
                if (len < sizeof(struct lppaca))
                        break;
                vpap = &tvcpu->arch.vpa;
                err = 0;
                break;

        case H_VPA_REG_DTL:             /* register DTL */
                if (len < sizeof(struct dtl_entry))
                        break;
                len -= len % sizeof(struct dtl_entry);

                /* Check that they have previously registered a VPA */
                err = H_RESOURCE;
                if (!vpa_is_registered(&tvcpu->arch.vpa))
                        break;

                vpap = &tvcpu->arch.dtl;
                err = 0;
                break;

        case H_VPA_REG_SLB:             /* register SLB shadow buffer */
                /* Check that they have previously registered a VPA */
                err = H_RESOURCE;
                if (!vpa_is_registered(&tvcpu->arch.vpa))
                        break;

                vpap = &tvcpu->arch.slb_shadow;
                err = 0;
                break;

        case H_VPA_DEREG_VPA:           /* deregister VPA */
                /* Check they don't still have a DTL or SLB buf registered */
                err = H_RESOURCE;
                if (vpa_is_registered(&tvcpu->arch.dtl) ||
                    vpa_is_registered(&tvcpu->arch.slb_shadow))
                        break;

                vpap = &tvcpu->arch.vpa;
                err = 0;
                break;

        case H_VPA_DEREG_DTL:           /* deregister DTL */
                vpap = &tvcpu->arch.dtl;
                err = 0;
                break;

        case H_VPA_DEREG_SLB:           /* deregister SLB shadow buffer */
                vpap = &tvcpu->arch.slb_shadow;
                err = 0;
                break;
        }

        if (vpap) {
                vpap->next_gpa = vpa;
                vpap->len = len;
                vpap->update_pending = 1;
        }

        spin_unlock(&tvcpu->arch.vpa_update_lock);

        return err;
}

static void kvmppc_update_vpa(struct kvm_vcpu *vcpu, struct kvmppc_vpa *vpap)
{
        struct kvm *kvm = vcpu->kvm;
        void *va;
        unsigned long nb;
        unsigned long gpa;

        /*
         * We need to pin the page pointed to by vpap->next_gpa,
         * but we can't call kvmppc_pin_guest_page under the lock
         * as it does get_user_pages() and down_read().  So we
         * have to drop the lock, pin the page, then get the lock
         * again and check that a new area didn't get registered
         * in the meantime.
         */
        for (;;) {
                gpa = vpap->next_gpa;
                spin_unlock(&vcpu->arch.vpa_update_lock);
                va = NULL;
                nb = 0;
                if (gpa)
                        va = kvmppc_pin_guest_page(kvm, gpa, &nb);
                spin_lock(&vcpu->arch.vpa_update_lock);
                if (gpa == vpap->next_gpa)
                        break;
                /* sigh... unpin that one and try again */
                if (va)
                        kvmppc_unpin_guest_page(kvm, va, gpa, false);
        }

        vpap->update_pending = 0;
        if (va && nb < vpap->len) {
                /*
                 * If it's now too short, it must be that userspace
                 * has changed the mappings underlying guest memory,
                 * so unregister the region.
                 */
                kvmppc_unpin_guest_page(kvm, va, gpa, false);
                va = NULL;
        }
        if (vpap->pinned_addr)
                kvmppc_unpin_guest_page(kvm, vpap->pinned_addr, vpap->gpa,
                                        vpap->dirty);
        vpap->gpa = gpa;
        vpap->pinned_addr = va;
        vpap->dirty = false;
        if (va)
                vpap->pinned_end = va + vpap->len;
}

static void kvmppc_update_vpas(struct kvm_vcpu *vcpu)
{
        if (!(vcpu->arch.vpa.update_pending ||
              vcpu->arch.slb_shadow.update_pending ||
              vcpu->arch.dtl.update_pending))
                return;

        spin_lock(&vcpu->arch.vpa_update_lock);
        if (vcpu->arch.vpa.update_pending) {
                kvmppc_update_vpa(vcpu, &vcpu->arch.vpa);
                if (vcpu->arch.vpa.pinned_addr)
                        init_vpa(vcpu, vcpu->arch.vpa.pinned_addr);
        }
        if (vcpu->arch.dtl.update_pending) {
                kvmppc_update_vpa(vcpu, &vcpu->arch.dtl);
                vcpu->arch.dtl_ptr = vcpu->arch.dtl.pinned_addr;
                vcpu->arch.dtl_index = 0;
        }
        if (vcpu->arch.slb_shadow.update_pending)
                kvmppc_update_vpa(vcpu, &vcpu->arch.slb_shadow);
        spin_unlock(&vcpu->arch.vpa_update_lock);
}

/*
 * Return the accumulated stolen time for the vcore up until `now'.
 * The caller should hold the vcore lock.
 */
static u64 vcore_stolen_time(struct kvmppc_vcore *vc, u64 now)
{
        u64 p;

        /*
         * If we are the task running the vcore, then since we hold
         * the vcore lock, we can't be preempted, so stolen_tb/preempt_tb
         * can't be updated, so we don't need the tbacct_lock.
         * If the vcore is inactive, it can't become active (since we
         * hold the vcore lock), so the vcpu load/put functions won't
         * update stolen_tb/preempt_tb, and we don't need tbacct_lock.
         */
        if (vc->vcore_state != VCORE_INACTIVE &&
            vc->runner->arch.run_task != current) {
                spin_lock(&vc->runner->arch.tbacct_lock);
                p = vc->stolen_tb;
                if (vc->preempt_tb != TB_NIL)
                        p += now - vc->preempt_tb;
                spin_unlock(&vc->runner->arch.tbacct_lock);
        } else {
                p = vc->stolen_tb;
        }
        return p;
}

static void kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
                                    struct kvmppc_vcore *vc)
{
        struct dtl_entry *dt;
        struct lppaca *vpa;
        unsigned long stolen;
        unsigned long core_stolen;
        u64 now;

        dt = vcpu->arch.dtl_ptr;
        vpa = vcpu->arch.vpa.pinned_addr;
        now = mftb();
        core_stolen = vcore_stolen_time(vc, now);
        stolen = core_stolen - vcpu->arch.stolen_logged;
        vcpu->arch.stolen_logged = core_stolen;
        spin_lock(&vcpu->arch.tbacct_lock);
        stolen += vcpu->arch.busy_stolen;
        vcpu->arch.busy_stolen = 0;
        spin_unlock(&vcpu->arch.tbacct_lock);
        if (!dt || !vpa)
                return;
        memset(dt, 0, sizeof(struct dtl_entry));
        dt->dispatch_reason = 7;
        dt->processor_id = vc->pcpu + vcpu->arch.ptid;
        dt->timebase = now;
        dt->enqueue_to_dispatch_time = stolen;
        dt->srr0 = kvmppc_get_pc(vcpu);
        dt->srr1 = vcpu->arch.shregs.msr;
        ++dt;
        if (dt == vcpu->arch.dtl.pinned_end)
                dt = vcpu->arch.dtl.pinned_addr;
        vcpu->arch.dtl_ptr = dt;
        /* order writing *dt vs. writing vpa->dtl_idx */
        smp_wmb();
        vpa->dtl_idx = ++vcpu->arch.dtl_index;
        vcpu->arch.dtl.dirty = true;
}

int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
{
        unsigned long req = kvmppc_get_gpr(vcpu, 3);
        unsigned long target, ret = H_SUCCESS;
        struct kvm_vcpu *tvcpu;
        int idx, rc;

        switch (req) {
        case H_ENTER:
                idx = srcu_read_lock(&vcpu->kvm->srcu);
                ret = kvmppc_virtmode_h_enter(vcpu, kvmppc_get_gpr(vcpu, 4),
                                              kvmppc_get_gpr(vcpu, 5),
                                              kvmppc_get_gpr(vcpu, 6),
                                              kvmppc_get_gpr(vcpu, 7));
                srcu_read_unlock(&vcpu->kvm->srcu, idx);
                break;
        case H_CEDE:
                break;
        case H_PROD:
                target = kvmppc_get_gpr(vcpu, 4);
                tvcpu = kvmppc_find_vcpu(vcpu->kvm, target);
                if (!tvcpu) {
                        ret = H_PARAMETER;
                        break;
                }
                tvcpu->arch.prodded = 1;
                smp_mb();
                if (vcpu->arch.ceded) {
                        if (waitqueue_active(&vcpu->wq)) {
                                wake_up_interruptible(&vcpu->wq);
                                vcpu->stat.halt_wakeup++;
                        }
                }
                break;
        case H_CONFER:
                break;
        case H_REGISTER_VPA:
                ret = do_h_register_vpa(vcpu, kvmppc_get_gpr(vcpu, 4),
                                        kvmppc_get_gpr(vcpu, 5),
                                        kvmppc_get_gpr(vcpu, 6));
                break;
        case H_RTAS:
                if (list_empty(&vcpu->kvm->arch.rtas_tokens))
                        return RESUME_HOST;

                rc = kvmppc_rtas_hcall(vcpu);

                if (rc == -ENOENT)
                        return RESUME_HOST;
                else if (rc == 0)
                        break;

                /* Send the error out to userspace via KVM_RUN */
                return rc;

        case H_XIRR:
        case H_CPPR:
        case H_EOI:
        case H_IPI:
                if (kvmppc_xics_enabled(vcpu)) {
                        ret = kvmppc_xics_hcall(vcpu, req);
                        break;
                } /* fallthrough */
        default:
                return RESUME_HOST;
        }
        kvmppc_set_gpr(vcpu, 3, ret);
        vcpu->arch.hcall_needed = 0;
        return RESUME_GUEST;
}

static int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
                              struct task_struct *tsk)
{
        int r = RESUME_HOST;

        vcpu->stat.sum_exits++;

        run->exit_reason = KVM_EXIT_UNKNOWN;
        run->ready_for_interrupt_injection = 1;
        switch (vcpu->arch.trap) {
        /* We're good on these - the host merely wanted to get our attention */
        case BOOK3S_INTERRUPT_HV_DECREMENTER:
                vcpu->stat.dec_exits++;
                r = RESUME_GUEST;
                break;
        case BOOK3S_INTERRUPT_EXTERNAL:
                vcpu->stat.ext_intr_exits++;
                r = RESUME_GUEST;
                break;
        case BOOK3S_INTERRUPT_PERFMON:
                r = RESUME_GUEST;
                break;
        case BOOK3S_INTERRUPT_MACHINE_CHECK:
                /*
                 * Deliver a machine check interrupt to the guest.
                 * We have to do this, even if the host has handled the
                 * machine check, because machine checks use SRR0/1 and
                 * the interrupt might have trashed guest state in them.
                 */
                kvmppc_book3s_queue_irqprio(vcpu,
                                            BOOK3S_INTERRUPT_MACHINE_CHECK);
                r = RESUME_GUEST;
                break;
        case BOOK3S_INTERRUPT_PROGRAM:
        {
                ulong flags;
                /*
                 * Normally program interrupts are delivered directly
                 * to the guest by the hardware, but we can get here
                 * as a result of a hypervisor emulation interrupt
                 * (e40) getting turned into a 700 by BML RTAS.
                 */
                flags = vcpu->arch.shregs.msr & 0x1f0000ull;
                kvmppc_core_queue_program(vcpu, flags);
                r = RESUME_GUEST;
                break;
        }
        case BOOK3S_INTERRUPT_SYSCALL:
        {
                /* hcall - punt to userspace */
                int i;

                if (vcpu->arch.shregs.msr & MSR_PR) {
                        /* sc 1 from userspace - reflect to guest syscall */
                        kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_SYSCALL);
                        r = RESUME_GUEST;
                        break;
                }
                run->papr_hcall.nr = kvmppc_get_gpr(vcpu, 3);
                for (i = 0; i < 9; ++i)
                        run->papr_hcall.args[i] = kvmppc_get_gpr(vcpu, 4 + i);
                run->exit_reason = KVM_EXIT_PAPR_HCALL;
                vcpu->arch.hcall_needed = 1;
                r = RESUME_HOST;
                break;
        }
        /*
         * We get these next two if the guest accesses a page which it thinks
         * it has mapped but which is not actually present, either because
         * it is for an emulated I/O device or because the corresonding
         * host page has been paged out.  Any other HDSI/HISI interrupts
         * have been handled already.
         */
        case BOOK3S_INTERRUPT_H_DATA_STORAGE:
                r = RESUME_PAGE_FAULT;
                break;
        case BOOK3S_INTERRUPT_H_INST_STORAGE:
                vcpu->arch.fault_dar = kvmppc_get_pc(vcpu);
                vcpu->arch.fault_dsisr = 0;
                r = RESUME_PAGE_FAULT;
                break;
        /*
         * This occurs if the guest executes an illegal instruction.
         * We just generate a program interrupt to the guest, since
         * we don't emulate any guest instructions at this stage.
         */
        case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
                kvmppc_core_queue_program(vcpu, 0x80000);
                r = RESUME_GUEST;
                break;
        default:
                kvmppc_dump_regs(vcpu);
                printk(KERN_EMERG "trap=0x%x | pc=0x%lx | msr=0x%llx\n",
                        vcpu->arch.trap, kvmppc_get_pc(vcpu),
                        vcpu->arch.shregs.msr);
                r = RESUME_HOST;
                BUG();
                break;
        }

        return r;
}

int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
                                  struct kvm_sregs *sregs)
{
        int i;

        sregs->pvr = vcpu->arch.pvr;

        memset(sregs, 0, sizeof(struct kvm_sregs));
        for (i = 0; i < vcpu->arch.slb_max; i++) {
                sregs->u.s.ppc64.slb[i].slbe = vcpu->arch.slb[i].orige;
                sregs->u.s.ppc64.slb[i].slbv = vcpu->arch.slb[i].origv;
        }

        return 0;
}

int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
                                  struct kvm_sregs *sregs)
{
        int i, j;

        kvmppc_set_pvr(vcpu, sregs->pvr);

        j = 0;
        for (i = 0; i < vcpu->arch.slb_nr; i++) {
                if (sregs->u.s.ppc64.slb[i].slbe & SLB_ESID_V) {
                        vcpu->arch.slb[j].orige = sregs->u.s.ppc64.slb[i].slbe;
                        vcpu->arch.slb[j].origv = sregs->u.s.ppc64.slb[i].slbv;
                        ++j;
                }
        }
        vcpu->arch.slb_max = j;

        return 0;
}

int kvmppc_get_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
{
        int r = 0;
        long int i;

        switch (id) {
        case KVM_REG_PPC_HIOR:
                *val = get_reg_val(id, 0);
                break;
        case KVM_REG_PPC_DABR:
                *val = get_reg_val(id, vcpu->arch.dabr);
                break;
        case KVM_REG_PPC_DSCR:
                *val = get_reg_val(id, vcpu->arch.dscr);
                break;
        case KVM_REG_PPC_PURR:
                *val = get_reg_val(id, vcpu->arch.purr);
                break;
        case KVM_REG_PPC_SPURR:
                *val = get_reg_val(id, vcpu->arch.spurr);
                break;
        case KVM_REG_PPC_AMR:
                *val = get_reg_val(id, vcpu->arch.amr);
                break;
        case KVM_REG_PPC_UAMOR:
                *val = get_reg_val(id, vcpu->arch.uamor);
                break;
        case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCRA:
                i = id - KVM_REG_PPC_MMCR0;
                *val = get_reg_val(id, vcpu->arch.mmcr[i]);
                break;
        case KVM_REG_PPC_PMC1 ... KVM_REG_PPC_PMC8:
                i = id - KVM_REG_PPC_PMC1;
                *val = get_reg_val(id, vcpu->arch.pmc[i]);
                break;
#ifdef CONFIG_VSX
        case KVM_REG_PPC_FPR0 ... KVM_REG_PPC_FPR31:
                if (cpu_has_feature(CPU_FTR_VSX)) {
                        /* VSX => FP reg i is stored in arch.vsr[2*i] */
                        long int i = id - KVM_REG_PPC_FPR0;
                        *val = get_reg_val(id, vcpu->arch.vsr[2 * i]);
                } else {
                        /* let generic code handle it */
                        r = -EINVAL;
                }
                break;
        case KVM_REG_PPC_VSR0 ... KVM_REG_PPC_VSR31:
                if (cpu_has_feature(CPU_FTR_VSX)) {
                        long int i = id - KVM_REG_PPC_VSR0;
                        val->vsxval[0] = vcpu->arch.vsr[2 * i];
                        val->vsxval[1] = vcpu->arch.vsr[2 * i + 1];
                } else {
                        r = -ENXIO;
                }
                break;
#endif /* CONFIG_VSX */
        case KVM_REG_PPC_VPA_ADDR:
                spin_lock(&vcpu->arch.vpa_update_lock);
                *val = get_reg_val(id, vcpu->arch.vpa.next_gpa);
                spin_unlock(&vcpu->arch.vpa_update_lock);
                break;
        case KVM_REG_PPC_VPA_SLB:
                spin_lock(&vcpu->arch.vpa_update_lock);
                val->vpaval.addr = vcpu->arch.slb_shadow.next_gpa;
                val->vpaval.length = vcpu->arch.slb_shadow.len;
                spin_unlock(&vcpu->arch.vpa_update_lock);
                break;
        case KVM_REG_PPC_VPA_DTL:
                spin_lock(&vcpu->arch.vpa_update_lock);
                val->vpaval.addr = vcpu->arch.dtl.next_gpa;
                val->vpaval.length = vcpu->arch.dtl.len;
                spin_unlock(&vcpu->arch.vpa_update_lock);
                break;
        default:
                r = -EINVAL;
                break;
        }

        return r;
}

int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val)
{
        int r = 0;
        long int i;
        unsigned long addr, len;

        switch (id) {
        case KVM_REG_PPC_HIOR:
                /* Only allow this to be set to zero */
                if (set_reg_val(id, *val))
                        r = -EINVAL;
                break;
        case KVM_REG_PPC_DABR:
                vcpu->arch.dabr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_DSCR:
                vcpu->arch.dscr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_PURR:
                vcpu->arch.purr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_SPURR:
                vcpu->arch.spurr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_AMR:
                vcpu->arch.amr = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_UAMOR:
                vcpu->arch.uamor = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCRA:
                i = id - KVM_REG_PPC_MMCR0;
                vcpu->arch.mmcr[i] = set_reg_val(id, *val);
                break;
        case KVM_REG_PPC_PMC1 ... KVM_REG_PPC_PMC8:
                i = id - KVM_REG_PPC_PMC1;
                vcpu->arch.pmc[i] = set_reg_val(id, *val);
                break;
#ifdef CONFIG_VSX
        case KVM_REG_PPC_FPR0 ... KVM_REG_PPC_FPR31:
                if (cpu_has_feature(CPU_FTR_VSX)) {
                        /* VSX => FP reg i is stored in arch.vsr[2*i] */
                        long int i = id - KVM_REG_PPC_FPR0;
                        vcpu->arch.vsr[2 * i] = set_reg_val(id, *val);
                } else {
                        /* let generic code handle it */
                        r = -EINVAL;
                }
                break;
        case KVM_REG_PPC_VSR0 ... KVM_REG_PPC_VSR31:
                if (cpu_has_feature(CPU_FTR_VSX)) {
                        long int i = id - KVM_REG_PPC_VSR0;
                        vcpu->arch.vsr[2 * i] = val->vsxval[0];
                        vcpu->arch.vsr[2 * i + 1] = val->vsxval[1];
                } else {
                        r = -ENXIO;
                }
                break;
#endif /* CONFIG_VSX */
        case KVM_REG_PPC_VPA_ADDR:
                addr = set_reg_val(id, *val);
                r = -EINVAL;
                if (!addr && (vcpu->arch.slb_shadow.next_gpa ||
                              vcpu->arch.dtl.next_gpa))
                        break;
                r = set_vpa(vcpu, &vcpu->arch.vpa, addr, sizeof(struct lppaca));
                break;
        case KVM_REG_PPC_VPA_SLB:
                addr = val->vpaval.addr;
                len = val->vpaval.length;
                r = -EINVAL;
                if (addr && !vcpu->arch.vpa.next_gpa)
                        break;
                r = set_vpa(vcpu, &vcpu->arch.slb_shadow, addr, len);
                break;
        case KVM_REG_PPC_VPA_DTL:
                addr = val->vpaval.addr;
                len = val->vpaval.length;
                r = -EINVAL;
                if (addr && (len < sizeof(struct dtl_entry) ||
                             !vcpu->arch.vpa.next_gpa))
                        break;
                len -= len % sizeof(struct dtl_entry);
                r = set_vpa(vcpu, &vcpu->arch.dtl, addr, len);
                break;
        default:
                r = -EINVAL;
                break;
        }

        return r;
}

int kvmppc_core_check_processor_compat(void)
{
        if (cpu_has_feature(CPU_FTR_HVMODE))
                return 0;
        return -EIO;
}

struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id)
{
        struct kvm_vcpu *vcpu;
        int err = -EINVAL;
        int core;
        struct kvmppc_vcore *vcore;

        core = id / threads_per_core;
        if (core >= KVM_MAX_VCORES)
                goto out;

        err = -ENOMEM;
        vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
        if (!vcpu)
                goto out;

        err = kvm_vcpu_init(vcpu, kvm, id);
        if (err)
                goto free_vcpu;

        vcpu->arch.shared = &vcpu->arch.shregs;
        vcpu->arch.mmcr[0] = MMCR0_FC;
        vcpu->arch.ctrl = CTRL_RUNLATCH;
        /* default to host PVR, since we can't spoof it */
        vcpu->arch.pvr = mfspr(SPRN_PVR);
        kvmppc_set_pvr(vcpu, vcpu->arch.pvr);
        spin_lock_init(&vcpu->arch.vpa_update_lock);
        spin_lock_init(&vcpu->arch.tbacct_lock);
        vcpu->arch.busy_preempt = TB_NIL;

        kvmppc_mmu_book3s_hv_init(vcpu);

        vcpu->arch.state = KVMPPC_VCPU_NOTREADY;

        init_waitqueue_head(&vcpu->arch.cpu_run);

        mutex_lock(&kvm->lock);
        vcore = kvm->arch.vcores[core];
        if (!vcore) {
                vcore = kzalloc(sizeof(struct kvmppc_vcore), GFP_KERNEL);
                if (vcore) {
                        INIT_LIST_HEAD(&vcore->runnable_threads);
                        spin_lock_init(&vcore->lock);
                        init_waitqueue_head(&vcore->wq);
                        vcore->preempt_tb = TB_NIL;
                }
                kvm->arch.vcores[core] = vcore;
                kvm->arch.online_vcores++;
        }
        mutex_unlock(&kvm->lock);

        if (!vcore)
                goto free_vcpu;

        spin_lock(&vcore->lock);
        ++vcore->num_threads;
        spin_unlock(&vcore->lock);
        vcpu->arch.vcore = vcore;

        vcpu->arch.cpu_type = KVM_CPU_3S_64;
        kvmppc_sanity_check(vcpu);

        return vcpu;

free_vcpu:
        kmem_cache_free(kvm_vcpu_cache, vcpu);
out:
        return ERR_PTR(err);
}

static void unpin_vpa(struct kvm *kvm, struct kvmppc_vpa *vpa)
{
        if (vpa->pinned_addr)
                kvmppc_unpin_guest_page(kvm, vpa->pinned_addr, vpa->gpa,
                                        vpa->dirty);
}

void kvmppc_core_vcpu_free(struct kvm_vcpu *vcpu)
{
        spin_lock(&vcpu->arch.vpa_update_lock);
        unpin_vpa(vcpu->kvm, &vcpu->arch.dtl);
        unpin_vpa(vcpu->kvm, &vcpu->arch.slb_shadow);
        unpin_vpa(vcpu->kvm, &vcpu->arch.vpa);
        spin_unlock(&vcpu->arch.vpa_update_lock);
        kvm_vcpu_uninit(vcpu);
        kmem_cache_free(kvm_vcpu_cache, vcpu);
}

static void kvmppc_set_timer(struct kvm_vcpu *vcpu)
{
        unsigned long dec_nsec, now;

        now = get_tb();
        if (now > vcpu->arch.dec_expires) {
                /* decrementer has already gone negative */
                kvmppc_core_queue_dec(vcpu);
                kvmppc_core_prepare_to_enter(vcpu);
                return;
        }
        dec_nsec = (vcpu->arch.dec_expires - now) * NSEC_PER_SEC
                   / tb_ticks_per_sec;
        hrtimer_start(&vcpu->arch.dec_timer, ktime_set(0, dec_nsec),
                      HRTIMER_MODE_REL);
        vcpu->arch.timer_running = 1;
}

static void kvmppc_end_cede(struct kvm_vcpu *vcpu)
{
        vcpu->arch.ceded = 0;
        if (vcpu->arch.timer_running) {
                hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
                vcpu->arch.timer_running = 0;
        }
}

extern int __kvmppc_vcore_entry(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu);

static void kvmppc_remove_runnable(struct kvmppc_vcore *vc,
                                   struct kvm_vcpu *vcpu)
{
        u64 now;

        if (vcpu->arch.state != KVMPPC_VCPU_RUNNABLE)
                return;
        spin_lock(&vcpu->arch.tbacct_lock);
        now = mftb();
        vcpu->arch.busy_stolen += vcore_stolen_time(vc, now) -
                vcpu->arch.stolen_logged;
        vcpu->arch.busy_preempt = now;
        vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;
        spin_unlock(&vcpu->arch.tbacct_lock);
        --vc->n_runnable;
        list_del(&vcpu->arch.run_list);
}

static int kvmppc_grab_hwthread(int cpu)
{
        struct paca_struct *tpaca;
        long timeout = 1000;

        tpaca = &paca[cpu];

        /* Ensure the thread won't go into the kernel if it wakes */
        tpaca->kvm_hstate.hwthread_req = 1;
        tpaca->kvm_hstate.kvm_vcpu = NULL;

        /*
         * If the thread is already executing in the kernel (e.g. handling
         * a stray interrupt), wait for it to get back to nap mode.
         * The smp_mb() is to ensure that our setting of hwthread_req
         * is visible before we look at hwthread_state, so if this
         * races with the code at system_reset_pSeries and the thread
         * misses our setting of hwthread_req, we are sure to see its
         * setting of hwthread_state, and vice versa.
         */
        smp_mb();
        while (tpaca->kvm_hstate.hwthread_state == KVM_HWTHREAD_IN_KERNEL) {
                if (--timeout <= 0) {
                        pr_err("KVM: couldn't grab cpu %d\n", cpu);
                        return -EBUSY;
                }
                udelay(1);
        }
        return 0;
}

static void kvmppc_release_hwthread(int cpu)
{
        struct paca_struct *tpaca;

        tpaca = &paca[cpu];
        tpaca->kvm_hstate.hwthread_req = 0;
        tpaca->kvm_hstate.kvm_vcpu = NULL;
}

static void kvmppc_start_thread(struct kvm_vcpu *vcpu)
{
        int cpu;
        struct paca_struct *tpaca;
        struct kvmppc_vcore *vc = vcpu->arch.vcore;

        if (vcpu->arch.timer_running) {
                hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
                vcpu->arch.timer_running = 0;
        }
        cpu = vc->pcpu + vcpu->arch.ptid;
        tpaca = &paca[cpu];
        tpaca->kvm_hstate.kvm_vcpu = vcpu;
        tpaca->kvm_hstate.kvm_vcore = vc;
        tpaca->kvm_hstate.napping = 0;
        vcpu->cpu = vc->pcpu;
        smp_wmb();
#if defined(CONFIG_PPC_ICP_NATIVE) && defined(CONFIG_SMP)
        if (vcpu->arch.ptid) {
                xics_wake_cpu(cpu);
                ++vc->n_woken;
        }
#endif
}

static void kvmppc_wait_for_nap(struct kvmppc_vcore *vc)
{
        int i;

        HMT_low();
        i = 0;
        while (vc->nap_count < vc->n_woken) {
                if (++i >= 1000000) {
                        pr_err("kvmppc_wait_for_nap timeout %d %d\n",
                               vc->nap_count, vc->n_woken);
                        break;
                }
                cpu_relax();
        }
        HMT_medium();
}

/*
 * Check that we are on thread 0 and that any other threads in
 * this core are off-line.  Then grab the threads so they can't
 * enter the kernel.
 */
static int on_primary_thread(void)
{
        int cpu = smp_processor_id();
        int thr = cpu_thread_in_core(cpu);

        if (thr)
                return 0;
        while (++thr < threads_per_core)
                if (cpu_online(cpu + thr))
                        return 0;

        /* Grab all hw threads so they can't go into the kernel */
        for (thr = 1; thr < threads_per_core; ++thr) {
                if (kvmppc_grab_hwthread(cpu + thr)) {
                        /* Couldn't grab one; let the others go */
                        do {
                                kvmppc_release_hwthread(cpu + thr);
                        } while (--thr > 0);
                        return 0;
                }
        }
        return 1;
}

/*
 * Run a set of guest threads on a physical core.
 * Called with vc->lock held.
 */
static void kvmppc_run_core(struct kvmppc_vcore *vc)
{
        struct kvm_vcpu *vcpu, *vcpu0, *vnext;
        long ret;
        u64 now;
        int ptid, i, need_vpa_update;
        int srcu_idx;
        struct kvm_vcpu *vcpus_to_update[threads_per_core];

        /* don't start if any threads have a signal pending */
        need_vpa_update = 0;
        list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list) {
                if (signal_pending(vcpu->arch.run_task))
                        return;
                if (vcpu->arch.vpa.update_pending ||
                    vcpu->arch.slb_shadow.update_pending ||
                    vcpu->arch.dtl.update_pending)
                        vcpus_to_update[need_vpa_update++] = vcpu;
        }

        /*
         * Initialize *vc, in particular vc->vcore_state, so we can
         * drop the vcore lock if necessary.
         */
        vc->n_woken = 0;
        vc->nap_count = 0;
        vc->entry_exit_count = 0;
        vc->vcore_state = VCORE_STARTING;
        vc->in_guest = 0;
        vc->napping_threads = 0;

        /*
         * Updating any of the vpas requires calling kvmppc_pin_guest_page,
         * which can't be called with any spinlocks held.
         */
        if (need_vpa_update) {
                spin_unlock(&vc->lock);
                for (i = 0; i < need_vpa_update; ++i)
                        kvmppc_update_vpas(vcpus_to_update[i]);
                spin_lock(&vc->lock);
        }

        /*
         * Assign physical thread IDs, first to non-ceded vcpus
         * and then to ceded ones.
         */
        ptid = 0;
        vcpu0 = NULL;
        list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list) {
                if (!vcpu->arch.ceded) {
                        if (!ptid)
                                vcpu0 = vcpu;
                        vcpu->arch.ptid = ptid++;
                }
        }
        if (!vcpu0)
                goto out;       /* nothing to run; should never happen */
        list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list)
                if (vcpu->arch.ceded)
                        vcpu->arch.ptid = ptid++;

        /*
         * Make sure we are running on thread 0, and that
         * secondary threads are offline.
         */
        if (threads_per_core > 1 && !on_primary_thread()) {
                list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list)
                        vcpu->arch.ret = -EBUSY;
                goto out;
        }

        vc->pcpu = smp_processor_id();
        list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list) {
                kvmppc_start_thread(vcpu);
                kvmppc_create_dtl_entry(vcpu, vc);
        }

        vc->vcore_state = VCORE_RUNNING;
        preempt_disable();
        spin_unlock(&vc->lock);

        kvm_guest_enter();

        srcu_idx = srcu_read_lock(&vcpu0->kvm->srcu);

        __kvmppc_vcore_entry(NULL, vcpu0);

        spin_lock(&vc->lock);
        /* disable sending of IPIs on virtual external irqs */
        list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list)
                vcpu->cpu = -1;
        /* wait for secondary threads to finish writing their state to memory */
        if (vc->nap_count < vc->n_woken)
                kvmppc_wait_for_nap(vc);
        for (i = 0; i < threads_per_core; ++i)
                kvmppc_release_hwthread(vc->pcpu + i);
        /* prevent other vcpu threads from doing kvmppc_start_thread() now */
        vc->vcore_state = VCORE_EXITING;
        spin_unlock(&vc->lock);

        srcu_read_unlock(&vcpu0->kvm->srcu, srcu_idx);

        /* make sure updates to secondary vcpu structs are visible now */
        smp_mb();
        kvm_guest_exit();

        preempt_enable();
        kvm_resched(vcpu);

        spin_lock(&vc->lock);
        now = get_tb();
        list_for_each_entry(vcpu, &vc->runnable_threads, arch.run_list) {
                /* cancel pending dec exception if dec is positive */
                if (now < vcpu->arch.dec_expires &&
                    kvmppc_core_pending_dec(vcpu))
                        kvmppc_core_dequeue_dec(vcpu);

                ret = RESUME_GUEST;
                if (vcpu->arch.trap)
                        ret = kvmppc_handle_exit(vcpu->arch.kvm_run, vcpu,
                                                 vcpu->arch.run_task);

                vcpu->arch.ret = ret;
                vcpu->arch.trap = 0;

                if (vcpu->arch.ceded) {
                        if (ret != RESUME_GUEST)
                                kvmppc_end_cede(vcpu);
                        else
                                kvmppc_set_timer(vcpu);
                }
        }

 out:
        vc->vcore_state = VCORE_INACTIVE;
        list_for_each_entry_safe(vcpu, vnext, &vc->runnable_threads,
                                 arch.run_list) {
                if (vcpu->arch.ret != RESUME_GUEST) {
                        kvmppc_remove_runnable(vc, vcpu);
                        wake_up(&vcpu->arch.cpu_run);
                }
        }
}

/*
 * Wait for some other vcpu thread to execute us, and
 * wake us up when we need to handle something in the host.
 */
static void kvmppc_wait_for_exec(struct kvm_vcpu *vcpu, int wait_state)
{
        DEFINE_WAIT(wait);

        prepare_to_wait(&vcpu->arch.cpu_run, &wait, wait_state);
        if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE)
                schedule();
        finish_wait(&vcpu->arch.cpu_run, &wait);
}

/*
 * All the vcpus in this vcore are idle, so wait for a decrementer
 * or external interrupt to one of the vcpus.  vc->lock is held.
 */
static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc)
{
        DEFINE_WAIT(wait);

        prepare_to_wait(&vc->wq, &wait, TASK_INTERRUPTIBLE);
        vc->vcore_state = VCORE_SLEEPING;
        spin_unlock(&vc->lock);
        schedule();
        finish_wait(&vc->wq, &wait);
        spin_lock(&vc->lock);
        vc->vcore_state = VCORE_INACTIVE;
}

static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
{
        int n_ceded;
        struct kvmppc_vcore *vc;
        struct kvm_vcpu *v, *vn;

        kvm_run->exit_reason = 0;
        vcpu->arch.ret = RESUME_GUEST;
        vcpu->arch.trap = 0;
        kvmppc_update_vpas(vcpu);

        /*
         * Synchronize with other threads in this virtual core
         */
        vc = vcpu->arch.vcore;
        spin_lock(&vc->lock);
        vcpu->arch.ceded = 0;
        vcpu->arch.run_task = current;
        vcpu->arch.kvm_run = kvm_run;
        vcpu->arch.stolen_logged = vcore_stolen_time(vc, mftb());
        vcpu->arch.state = KVMPPC_VCPU_RUNNABLE;
        vcpu->arch.busy_preempt = TB_NIL;
        list_add_tail(&vcpu->arch.run_list, &vc->runnable_threads);
        ++vc->n_runnable;

        /*
         * This happens the first time this is called for a vcpu.
         * If the vcore is already running, we may be able to start
         * this thread straight away and have it join in.
         */
        if (!signal_pending(current)) {
                if (vc->vcore_state == VCORE_RUNNING &&
                    VCORE_EXIT_COUNT(vc) == 0) {
                        vcpu->arch.ptid = vc->n_runnable - 1;
                        kvmppc_create_dtl_entry(vcpu, vc);
                        kvmppc_start_thread(vcpu);
                } else if (vc->vcore_state == VCORE_SLEEPING) {
                        wake_up(&vc->wq);
                }

        }

        while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE &&
               !signal_pending(current)) {
                if (vc->vcore_state != VCORE_INACTIVE) {
                        spin_unlock(&vc->lock);
                        kvmppc_wait_for_exec(vcpu, TASK_INTERRUPTIBLE);
                        spin_lock(&vc->lock);
                        continue;
                }
                list_for_each_entry_safe(v, vn, &vc->runnable_threads,
                                         arch.run_list) {
                        kvmppc_core_prepare_to_enter(v);
                        if (signal_pending(v->arch.run_task)) {
                                kvmppc_remove_runnable(vc, v);
                                v->stat.signal_exits++;
                                v->arch.kvm_run->exit_reason = KVM_EXIT_INTR;
                                v->arch.ret = -EINTR;
                                wake_up(&v->arch.cpu_run);
                        }
                }
                if (!vc->n_runnable || vcpu->arch.state != KVMPPC_VCPU_RUNNABLE)
                        break;
                vc->runner = vcpu;
                n_ceded = 0;
                list_for_each_entry(v, &vc->runnable_threads, arch.run_list) {
                        if (!v->arch.pending_exceptions)
                                n_ceded += v->arch.ceded;
                        else
                                v->arch.ceded = 0;
                }
                if (n_ceded == vc->n_runnable)
                        kvmppc_vcore_blocked(vc);
                else
                        kvmppc_run_core(vc);
                vc->runner = NULL;
        }

        while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE &&
               (vc->vcore_state == VCORE_RUNNING ||
                vc->vcore_state == VCORE_EXITING)) {
                spin_unlock(&vc->lock);
                kvmppc_wait_for_exec(vcpu, TASK_UNINTERRUPTIBLE);
                spin_lock(&vc->lock);
        }

        if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE) {
                kvmppc_remove_runnable(vc, vcpu);
                vcpu->stat.signal_exits++;
                kvm_run->exit_reason = KVM_EXIT_INTR;
                vcpu->arch.ret = -EINTR;
        }

        if (vc->n_runnable && vc->vcore_state == VCORE_INACTIVE) {
                /* Wake up some vcpu to run the core */
                v = list_first_entry(&vc->runnable_threads,
                                     struct kvm_vcpu, arch.run_list);
                wake_up(&v->arch.cpu_run);
        }

        spin_unlock(&vc->lock);
        return vcpu->arch.ret;
}

int kvmppc_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
        int r;
        int srcu_idx;

        if (!vcpu->arch.sane) {
                run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
                return -EINVAL;
        }

        kvmppc_core_prepare_to_enter(vcpu);

        /* No need to go into the guest when all we'll do is come back out */
        if (signal_pending(current)) {
                run->exit_reason = KVM_EXIT_INTR;
                return -EINTR;
        }

        atomic_inc(&vcpu->kvm->arch.vcpus_running);
        /* Order vcpus_running vs. rma_setup_done, see kvmppc_alloc_reset_hpt */
        smp_mb();

        /* On the first time here, set up HTAB and VRMA or RMA */
        if (!vcpu->kvm->arch.rma_setup_done) {
                r = kvmppc_hv_setup_htab_rma(vcpu);
                if (r)
                        goto out;
        }

        flush_fp_to_thread(current);
        flush_altivec_to_thread(current);
        flush_vsx_to_thread(current);
        vcpu->arch.wqp = &vcpu->arch.vcore->wq;
        vcpu->arch.pgdir = current->mm->pgd;
        vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;

        do {
                r = kvmppc_run_vcpu(run, vcpu);

                if (run->exit_reason == KVM_EXIT_PAPR_HCALL &&
                    !(vcpu->arch.shregs.msr & MSR_PR)) {
                        r = kvmppc_pseries_do_hcall(vcpu);
                        kvmppc_core_prepare_to_enter(vcpu);
                } else if (r == RESUME_PAGE_FAULT) {
                        srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
                        r = kvmppc_book3s_hv_page_fault(run, vcpu,
                                vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
                        srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
                }
        } while (r == RESUME_GUEST);

 out:
        vcpu->arch.state = KVMPPC_VCPU_NOTREADY;
        atomic_dec(&vcpu->kvm->arch.vcpus_running);
        return r;
}


/* Work out RMLS (real mode limit selector) field value for a given RMA size.
   Assumes POWER7 or PPC970. */
static inline int lpcr_rmls(unsigned long rma_size)
{
        switch (rma_size) {
        case 32ul << 20:        /* 32 MB */
                if (cpu_has_feature(CPU_FTR_ARCH_206))
                        return 8;       /* only supported on POWER7 */
                return -1;
        case 64ul << 20:        /* 64 MB */
                return 3;
        case 128ul << 20:       /* 128 MB */
                return 7;
        case 256ul << 20:       /* 256 MB */
                return 4;
        case 1ul << 30:         /* 1 GB */
                return 2;
        case 16ul << 30:        /* 16 GB */
                return 1;
        case 256ul << 30:       /* 256 GB */
                return 0;
        default:
                return -1;
        }
}

static int kvm_rma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
        struct kvmppc_linear_info *ri = vma->vm_file->private_data;
        struct page *page;

        if (vmf->pgoff >= ri->npages)
                return VM_FAULT_SIGBUS;

        page = pfn_to_page(ri->base_pfn + vmf->pgoff);
        get_page(page);
        vmf->page = page;
        return 0;
}

static const struct vm_operations_struct kvm_rma_vm_ops = {
        .fault = kvm_rma_fault,
};

static int kvm_rma_mmap(struct file *file, struct vm_area_struct *vma)
{
        vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
        vma->vm_ops = &kvm_rma_vm_ops;
        return 0;
}

static int kvm_rma_release(struct inode *inode, struct file *filp)
{
        struct kvmppc_linear_info *ri = filp->private_data;

        kvm_release_rma(ri);
        return 0;
}

static const struct file_operations kvm_rma_fops = {
        .mmap           = kvm_rma_mmap,
        .release        = kvm_rma_release,
};

long kvm_vm_ioctl_allocate_rma(struct kvm *kvm, struct kvm_allocate_rma *ret)
{
        struct kvmppc_linear_info *ri;
        long fd;

        ri = kvm_alloc_rma();
        if (!ri)
                return -ENOMEM;

        fd = anon_inode_getfd("kvm-rma", &kvm_rma_fops, ri, O_RDWR);
        if (fd < 0)
                kvm_release_rma(ri);

        ret->rma_size = ri->npages << PAGE_SHIFT;
        return fd;
}

static void kvmppc_add_seg_page_size(struct kvm_ppc_one_seg_page_size **sps,
                                     int linux_psize)
{
        struct mmu_psize_def *def = &mmu_psize_defs[linux_psize];

        if (!def->shift)
                return;
        (*sps)->page_shift = def->shift;
        (*sps)->slb_enc = def->sllp;
        (*sps)->enc[0].page_shift = def->shift;
        /*
         * Only return base page encoding. We don't want to return
         * all the supporting pte_enc, because our H_ENTER doesn't
         * support MPSS yet. Once they do, we can start passing all
         * support pte_enc here
         */
        (*sps)->enc[0].pte_enc = def->penc[linux_psize];
        (*sps)++;
}

int kvm_vm_ioctl_get_smmu_info(struct kvm *kvm, struct kvm_ppc_smmu_info *info)
{
        struct kvm_ppc_one_seg_page_size *sps;

        info->flags = KVM_PPC_PAGE_SIZES_REAL;
        if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
                info->flags |= KVM_PPC_1T_SEGMENTS;
        info->slb_size = mmu_slb_size;

        /* We only support these sizes for now, and no muti-size segments */
        sps = &info->sps[0];
        kvmppc_add_seg_page_size(&sps, MMU_PAGE_4K);
        kvmppc_add_seg_page_size(&sps, MMU_PAGE_64K);
        kvmppc_add_seg_page_size(&sps, MMU_PAGE_16M);

        return 0;
}

/*
 * Get (and clear) the dirty memory log for a memory slot.
 */
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
{
        struct kvm_memory_slot *memslot;
        int r;
        unsigned long n;

        mutex_lock(&kvm->slots_lock);

        r = -EINVAL;
        if (log->slot >= KVM_USER_MEM_SLOTS)
                goto out;

        memslot = id_to_memslot(kvm->memslots, log->slot);
        r = -ENOENT;
        if (!memslot->dirty_bitmap)
                goto out;

        n = kvm_dirty_bitmap_bytes(memslot);
        memset(memslot->dirty_bitmap, 0, n);

        r = kvmppc_hv_get_dirty_log(kvm, memslot, memslot->dirty_bitmap);
        if (r)
                goto out;

        r = -EFAULT;
        if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
                goto out;

        r = 0;
out:
        mutex_unlock(&kvm->slots_lock);
        return r;
}

static void unpin_slot(struct kvm_memory_slot *memslot)
{
        unsigned long *physp;
        unsigned long j, npages, pfn;
        struct page *page;

        physp = memslot->arch.slot_phys;
        npages = memslot->npages;
        if (!physp)
                return;
        for (j = 0; j < npages; j++) {
                if (!(physp[j] & KVMPPC_GOT_PAGE))
                        continue;
                pfn = physp[j] >> PAGE_SHIFT;
                page = pfn_to_page(pfn);
                SetPageDirty(page);
                put_page(page);
        }
}

void kvmppc_core_free_memslot(struct kvm_memory_slot *free,
                              struct kvm_memory_slot *dont)
{
        if (!dont || free->arch.rmap != dont->arch.rmap) {
                vfree(free->arch.rmap);
                free->arch.rmap = NULL;
        }
        if (!dont || free->arch.slot_phys != dont->arch.slot_phys) {
                unpin_slot(free);
                vfree(free->arch.slot_phys);
                free->arch.slot_phys = NULL;
        }
}

int kvmppc_core_create_memslot(struct kvm_memory_slot *slot,
                               unsigned long npages)
{
        slot->arch.rmap = vzalloc(npages * sizeof(*slot->arch.rmap));
        if (!slot->arch.rmap)
                return -ENOMEM;
        slot->arch.slot_phys = NULL;

        return 0;
}

int kvmppc_core_prepare_memory_region(struct kvm *kvm,
                                      struct kvm_memory_slot *memslot,
                                      struct kvm_userspace_memory_region *mem)
{
        unsigned long *phys;

        /* Allocate a slot_phys array if needed */
        phys = memslot->arch.slot_phys;
        if (!kvm->arch.using_mmu_notifiers && !phys && memslot->npages) {
                phys = vzalloc(memslot->npages * sizeof(unsigned long));
                if (!phys)
                        return -ENOMEM;
                memslot->arch.slot_phys = phys;
        }

        return 0;
}

void kvmppc_core_commit_memory_region(struct kvm *kvm,
                                      struct kvm_userspace_memory_region *mem,
                                      const struct kvm_memory_slot *old)
{
        unsigned long npages = mem->memory_size >> PAGE_SHIFT;
        struct kvm_memory_slot *memslot;

        if (npages && old->npages) {
                /*
                 * If modifying a memslot, reset all the rmap dirty bits.
                 * If this is a new memslot, we don't need to do anything
                 * since the rmap array starts out as all zeroes,
                 * i.e. no pages are dirty.
                 */
                memslot = id_to_memslot(kvm->memslots, mem->slot);
                kvmppc_hv_get_dirty_log(kvm, memslot, NULL);
        }
}

static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
{
        int err = 0;
        struct kvm *kvm = vcpu->kvm;
        struct kvmppc_linear_info *ri = NULL;
        unsigned long hva;
        struct kvm_memory_slot *memslot;
        struct vm_area_struct *vma;
        unsigned long lpcr, senc;
        unsigned long psize, porder;
        unsigned long rma_size;
        unsigned long rmls;
        unsigned long *physp;
        unsigned long i, npages;
        int srcu_idx;

        mutex_lock(&kvm->lock);
        if (kvm->arch.rma_setup_done)
                goto out;       /* another vcpu beat us to it */

        /* Allocate hashed page table (if not done already) and reset it */
        if (!kvm->arch.hpt_virt) {
                err = kvmppc_alloc_hpt(kvm, NULL);
                if (err) {
                        pr_err("KVM: Couldn't alloc HPT\n");
                        goto out;
                }
        }

        /* Look up the memslot for guest physical address 0 */
        srcu_idx = srcu_read_lock(&kvm->srcu);
        memslot = gfn_to_memslot(kvm, 0);

        /* We must have some memory at 0 by now */
        err = -EINVAL;
        if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
                goto out_srcu;

        /* Look up the VMA for the start of this memory slot */
        hva = memslot->userspace_addr;
        down_read(&current->mm->mmap_sem);
        vma = find_vma(current->mm, hva);
        if (!vma || vma->vm_start > hva || (vma->vm_flags & VM_IO))
                goto up_out;

        psize = vma_kernel_pagesize(vma);
        porder = __ilog2(psize);

        /* Is this one of our preallocated RMAs? */
        if (vma->vm_file && vma->vm_file->f_op == &kvm_rma_fops &&
            hva == vma->vm_start)
                ri = vma->vm_file->private_data;

        up_read(&current->mm->mmap_sem);

        if (!ri) {
                /* On POWER7, use VRMA; on PPC970, give up */
                err = -EPERM;
                if (cpu_has_feature(CPU_FTR_ARCH_201)) {
                        pr_err("KVM: CPU requires an RMO\n");
                        goto out_srcu;
                }

                /* We can handle 4k, 64k or 16M pages in the VRMA */
                err = -EINVAL;
                if (!(psize == 0x1000 || psize == 0x10000 ||
                      psize == 0x1000000))
                        goto out_srcu;

                /* Update VRMASD field in the LPCR */
                senc = slb_pgsize_encoding(psize);
                kvm->arch.vrma_slb_v = senc | SLB_VSID_B_1T |
                        (VRMA_VSID << SLB_VSID_SHIFT_1T);
                lpcr = kvm->arch.lpcr & ~LPCR_VRMASD;
                lpcr |= senc << (LPCR_VRMASD_SH - 4);
                kvm->arch.lpcr = lpcr;

                /* Create HPTEs in the hash page table for the VRMA */
                kvmppc_map_vrma(vcpu, memslot, porder);

        } else {
                /* Set up to use an RMO region */
                rma_size = ri->npages;
                if (rma_size > memslot->npages)
                        rma_size = memslot->npages;
                rma_size <<= PAGE_SHIFT;
                rmls = lpcr_rmls(rma_size);
                err = -EINVAL;
                if (rmls < 0) {
                        pr_err("KVM: Can't use RMA of 0x%lx bytes\n", rma_size);
                        goto out_srcu;
                }
                atomic_inc(&ri->use_count);
                kvm->arch.rma = ri;

                /* Update LPCR and RMOR */
                lpcr = kvm->arch.lpcr;
                if (cpu_has_feature(CPU_FTR_ARCH_201)) {
                        /* PPC970; insert RMLS value (split field) in HID4 */
                        lpcr &= ~((1ul << HID4_RMLS0_SH) |
                                  (3ul << HID4_RMLS2_SH));
                        lpcr |= ((rmls >> 2) << HID4_RMLS0_SH) |
                                ((rmls & 3) << HID4_RMLS2_SH);
                        /* RMOR is also in HID4 */
                        lpcr |= ((ri->base_pfn >> (26 - PAGE_SHIFT)) & 0xffff)
                                << HID4_RMOR_SH;
                } else {
                        /* POWER7 */
                        lpcr &= ~(LPCR_VPM0 | LPCR_VRMA_L);
                        lpcr |= rmls << LPCR_RMLS_SH;
                        kvm->arch.rmor = kvm->arch.rma->base_pfn << PAGE_SHIFT;
                }
                kvm->arch.lpcr = lpcr;
                pr_info("KVM: Using RMO at %lx size %lx (LPCR = %lx)\n",
                        ri->base_pfn << PAGE_SHIFT, rma_size, lpcr);

                /* Initialize phys addrs of pages in RMO */
                npages = ri->npages;
                porder = __ilog2(npages);
                physp = memslot->arch.slot_phys;
                if (physp) {
                        if (npages > memslot->npages)
                                npages = memslot->npages;
                        spin_lock(&kvm->arch.slot_phys_lock);
                        for (i = 0; i < npages; ++i)
                                physp[i] = ((ri->base_pfn + i) << PAGE_SHIFT) +
                                        porder;
                        spin_unlock(&kvm->arch.slot_phys_lock);
                }
        }

        /* Order updates to kvm->arch.lpcr etc. vs. rma_setup_done */
        smp_wmb();
        kvm->arch.rma_setup_done = 1;
        err = 0;
 out_srcu:
        srcu_read_unlock(&kvm->srcu, srcu_idx);
 out:
        mutex_unlock(&kvm->lock);
        return err;

 up_out:
        up_read(&current->mm->mmap_sem);
        goto out;
}

int kvmppc_core_init_vm(struct kvm *kvm)
{
        unsigned long lpcr, lpid;

        /* Allocate the guest's logical partition ID */

        lpid = kvmppc_alloc_lpid();
        if (lpid < 0)
                return -ENOMEM;
        kvm->arch.lpid = lpid;

        /*
         * Since we don't flush the TLB when tearing down a VM,
         * and this lpid might have previously been used,
         * make sure we flush on each core before running the new VM.
         */
        cpumask_setall(&kvm->arch.need_tlb_flush);

        INIT_LIST_HEAD(&kvm->arch.spapr_tce_tables);
        INIT_LIST_HEAD(&kvm->arch.rtas_tokens);

        kvm->arch.rma = NULL;

        kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);

        if (cpu_has_feature(CPU_FTR_ARCH_201)) {
                /* PPC970; HID4 is effectively the LPCR */
                kvm->arch.host_lpid = 0;
                kvm->arch.host_lpcr = lpcr = mfspr(SPRN_HID4);
                lpcr &= ~((3 << HID4_LPID1_SH) | (0xful << HID4_LPID5_SH));
                lpcr |= ((lpid >> 4) << HID4_LPID1_SH) |
                        ((lpid & 0xf) << HID4_LPID5_SH);
        } else {
                /* POWER7; init LPCR for virtual RMA mode */
                kvm->arch.host_lpid = mfspr(SPRN_LPID);
                kvm->arch.host_lpcr = lpcr = mfspr(SPRN_LPCR);
                lpcr &= LPCR_PECE | LPCR_LPES;
                lpcr |= (4UL << LPCR_DPFD_SH) | LPCR_HDICE |
                        LPCR_VPM0 | LPCR_VPM1;
                kvm->arch.vrma_slb_v = SLB_VSID_B_1T |
                        (VRMA_VSID << SLB_VSID_SHIFT_1T);
        }
        kvm->arch.lpcr = lpcr;

        kvm->arch.using_mmu_notifiers = !!cpu_has_feature(CPU_FTR_ARCH_206);
        spin_lock_init(&kvm->arch.slot_phys_lock);

        /*
         * Don't allow secondary CPU threads to come online
         * while any KVM VMs exist.
         */
        inhibit_secondary_onlining();

        return 0;
}

void kvmppc_core_destroy_vm(struct kvm *kvm)
{
        uninhibit_secondary_onlining();

        if (kvm->arch.rma) {
                kvm_release_rma(kvm->arch.rma);
                kvm->arch.rma = NULL;
        }

        kvmppc_rtas_tokens_free(kvm);

        kvmppc_free_hpt(kvm);
        WARN_ON(!list_empty(&kvm->arch.spapr_tce_tables));
}

/* These are stubs for now */
void kvmppc_mmu_pte_pflush(struct kvm_vcpu *vcpu, ulong pa_start, ulong pa_end)
{
}

/* We don't need to emulate any privileged instructions or dcbz */
int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
                           unsigned int inst, int *advance)
{
        return EMULATE_FAIL;
}

int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
{
        return EMULATE_FAIL;
}

int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val)
{
        return EMULATE_FAIL;
}

static int kvmppc_book3s_hv_init(void)
{
        int r;

        r = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);

        if (r)
                return r;

        r = kvmppc_mmu_hv_init();

        return r;
}

static void kvmppc_book3s_hv_exit(void)
{
        kvm_exit();
}

module_init(kvmppc_book3s_hv_init);
module_exit(kvmppc_book3s_hv_exit);