/*
 * Dimm device for Memory Hotplug
 *
 * Copyright ProfitBricks GmbH 2012
 * Copyright (C) 2014 Red Hat Inc
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>
 */

#include "qemu/osdep.h"
#include "hw/mem/pc-dimm.h"
#include "hw/mem/nvdimm.h"
#include "qapi/error.h"
#include "qemu/config-file.h"
#include "qapi/visitor.h"
#include "qemu/range.h"
#include "sysemu/numa.h"
#include "sysemu/kvm.h"
#include "trace.h"
#include "hw/virtio/vhost.h"

typedef struct pc_dimms_capacity {
     uint64_t size;
     Error    **errp;
} pc_dimms_capacity;

void pc_dimm_memory_plug(DeviceState *dev, MemoryHotplugState *hpms,
                         MemoryRegion *mr, uint64_t align, Error **errp)
{
    int slot;
    MachineState *machine = MACHINE(qdev_get_machine());
    PCDIMMDevice *dimm = PC_DIMM(dev);
    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
    MemoryRegion *vmstate_mr = ddc->get_vmstate_memory_region(dimm);
    Error *local_err = NULL;
    uint64_t existing_dimms_capacity = 0;
    uint64_t addr;

    addr = object_property_get_uint(OBJECT(dimm),
                                    PC_DIMM_ADDR_PROP, &local_err);
    if (local_err) {
        goto out;
    }

    addr = pc_dimm_get_free_addr(hpms->base,
                                 memory_region_size(&hpms->mr),
                                 !addr ? NULL : &addr, align,
                                 memory_region_size(mr), &local_err);
    if (local_err) {
        goto out;
    }

    existing_dimms_capacity = pc_existing_dimms_capacity(&local_err);
    if (local_err) {
        goto out;
    }

    if (existing_dimms_capacity + memory_region_size(mr) >
        machine->maxram_size - machine->ram_size) {
        error_setg(&local_err, "not enough space, currently 0x%" PRIx64
                   " in use of total hot pluggable 0x" RAM_ADDR_FMT,
                   existing_dimms_capacity,
                   machine->maxram_size - machine->ram_size);
        goto out;
    }

    object_property_set_uint(OBJECT(dev), addr, PC_DIMM_ADDR_PROP, &local_err);
    if (local_err) {
        goto out;
    }
    trace_mhp_pc_dimm_assigned_address(addr);

    slot = object_property_get_int(OBJECT(dev), PC_DIMM_SLOT_PROP, &local_err);
    if (local_err) {
        goto out;
    }

    slot = pc_dimm_get_free_slot(slot == PC_DIMM_UNASSIGNED_SLOT ? NULL : &slot,
                                 machine->ram_slots, &local_err);
    if (local_err) {
        goto out;
    }
    object_property_set_int(OBJECT(dev), slot, PC_DIMM_SLOT_PROP, &local_err);
    if (local_err) {
        goto out;
    }
    trace_mhp_pc_dimm_assigned_slot(slot);

    if (kvm_enabled() && !kvm_has_free_slot(machine)) {
        error_setg(&local_err, "hypervisor has no free memory slots left");
        goto out;
    }

    if (!vhost_has_free_slot()) {
        error_setg(&local_err, "a used vhost backend has no free"
                               " memory slots left");
        goto out;
    }

    memory_region_add_subregion(&hpms->mr, addr - hpms->base, mr);
    vmstate_register_ram(vmstate_mr, dev);

out:
    error_propagate(errp, local_err);
}

void pc_dimm_memory_unplug(DeviceState *dev, MemoryHotplugState *hpms,
                           MemoryRegion *mr)
{
    PCDIMMDevice *dimm = PC_DIMM(dev);
    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
    MemoryRegion *vmstate_mr = ddc->get_vmstate_memory_region(dimm);

    memory_region_del_subregion(&hpms->mr, mr);
    vmstate_unregister_ram(vmstate_mr, dev);
}

static int pc_existing_dimms_capacity_internal(Object *obj, void *opaque)
{
    pc_dimms_capacity *cap = opaque;
    uint64_t *size = &cap->size;

    if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
        DeviceState *dev = DEVICE(obj);

        if (dev->realized) {
            (*size) += object_property_get_uint(obj, PC_DIMM_SIZE_PROP,
                cap->errp);
        }

        if (cap->errp && *cap->errp) {
            return 1;
        }
    }
    object_child_foreach(obj, pc_existing_dimms_capacity_internal, opaque);
    return 0;
}

uint64_t pc_existing_dimms_capacity(Error **errp)
{
    pc_dimms_capacity cap;

    cap.size = 0;
    cap.errp = errp;

    pc_existing_dimms_capacity_internal(qdev_get_machine(), &cap);
    return cap.size;
}

uint64_t get_plugged_memory_size(void)
{
    return pc_existing_dimms_capacity(&error_abort);
}

static int pc_dimm_slot2bitmap(Object *obj, void *opaque)
{
    unsigned long *bitmap = opaque;

    if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
        DeviceState *dev = DEVICE(obj);
        if (dev->realized) { /* count only realized DIMMs */
            PCDIMMDevice *d = PC_DIMM(obj);
            set_bit(d->slot, bitmap);
        }
    }

    object_child_foreach(obj, pc_dimm_slot2bitmap, opaque);
    return 0;
}

int pc_dimm_get_free_slot(const int *hint, int max_slots, Error **errp)
{
    unsigned long *bitmap = bitmap_new(max_slots);
    int slot = 0;

    object_child_foreach(qdev_get_machine(), pc_dimm_slot2bitmap, bitmap);

    /* check if requested slot is not occupied */
    if (hint) {
        if (*hint >= max_slots) {
            error_setg(errp, "invalid slot# %d, should be less than %d",
                       *hint, max_slots);
        } else if (!test_bit(*hint, bitmap)) {
            slot = *hint;
        } else {
            error_setg(errp, "slot %d is busy", *hint);
        }
        goto out;
    }

    /* search for free slot */
    slot = find_first_zero_bit(bitmap, max_slots);
    if (slot == max_slots) {
        error_setg(errp, "no free slots available");
    }
out:
    g_free(bitmap);
    return slot;
}

static gint pc_dimm_addr_sort(gconstpointer a, gconstpointer b)
{
    PCDIMMDevice *x = PC_DIMM(a);
    PCDIMMDevice *y = PC_DIMM(b);
    Int128 diff = int128_sub(int128_make64(x->addr), int128_make64(y->addr));

    if (int128_lt(diff, int128_zero())) {
        return -1;
    } else if (int128_gt(diff, int128_zero())) {
        return 1;
    }
    return 0;
}

static int pc_dimm_built_list(Object *obj, void *opaque)
{
    GSList **list = opaque;

    if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
        DeviceState *dev = DEVICE(obj);
        if (dev->realized) { /* only realized DIMMs matter */
            *list = g_slist_insert_sorted(*list, dev, pc_dimm_addr_sort);
        }
    }

    object_child_foreach(obj, pc_dimm_built_list, opaque);
    return 0;
}

MemoryDeviceInfoList *qmp_pc_dimm_device_list(void)
{
    GSList *dimms = NULL, *item;
    MemoryDeviceInfoList *list = NULL, *prev = NULL;

    object_child_foreach(qdev_get_machine(), pc_dimm_built_list, &dimms);

    for (item = dimms; item; item = g_slist_next(item)) {
        PCDIMMDevice *dimm = PC_DIMM(item->data);
        Object *obj = OBJECT(dimm);
        MemoryDeviceInfoList *elem = g_new0(MemoryDeviceInfoList, 1);
        MemoryDeviceInfo *info = g_new0(MemoryDeviceInfo, 1);
        PCDIMMDeviceInfo *di = g_new0(PCDIMMDeviceInfo, 1);
        bool is_nvdimm = object_dynamic_cast(obj, TYPE_NVDIMM);
        DeviceClass *dc = DEVICE_GET_CLASS(obj);
        DeviceState *dev = DEVICE(obj);

        if (dev->id) {
            di->has_id = true;
            di->id = g_strdup(dev->id);
        }
        di->hotplugged = dev->hotplugged;
        di->hotpluggable = dc->hotpluggable;
        di->addr = dimm->addr;
        di->slot = dimm->slot;
        di->node = dimm->node;
        di->size = object_property_get_uint(obj, PC_DIMM_SIZE_PROP, NULL);
        di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));

        if (!is_nvdimm) {
            info->u.dimm.data = di;
            info->type = MEMORY_DEVICE_INFO_KIND_DIMM;
        } else {
            info->u.nvdimm.data = di;
            info->type = MEMORY_DEVICE_INFO_KIND_NVDIMM;
        }
        elem->value = info;
        elem->next = NULL;
        if (prev) {
            prev->next = elem;
        } else {
            list = elem;
        }
        prev = elem;
    }

    g_slist_free(dimms);

    return list;
}

uint64_t pc_dimm_get_free_addr(uint64_t address_space_start,
                               uint64_t address_space_size,
                               uint64_t *hint, uint64_t align, uint64_t size,
                               Error **errp)
{
    GSList *list = NULL, *item;
    uint64_t new_addr, ret = 0;
    uint64_t address_space_end = address_space_start + address_space_size;

    g_assert(QEMU_ALIGN_UP(address_space_start, align) == address_space_start);

    if (!address_space_size) {
        error_setg(errp, "memory hotplug is not enabled, "
                         "please add maxmem option");
        goto out;
    }

    if (hint && QEMU_ALIGN_UP(*hint, align) != *hint) {
        error_setg(errp, "address must be aligned to 0x%" PRIx64 " bytes",
                   align);
        goto out;
    }

    if (QEMU_ALIGN_UP(size, align) != size) {
        error_setg(errp, "backend memory size must be multiple of 0x%"
                   PRIx64, align);
        goto out;
    }

    assert(address_space_end > address_space_start);
    object_child_foreach(qdev_get_machine(), pc_dimm_built_list, &list);

    if (hint) {
        new_addr = *hint;
    } else {
        new_addr = address_space_start;
    }

    /* find address range that will fit new DIMM */
    for (item = list; item; item = g_slist_next(item)) {
        PCDIMMDevice *dimm = item->data;
        uint64_t dimm_size = object_property_get_uint(OBJECT(dimm),
                                                      PC_DIMM_SIZE_PROP,
                                                      errp);
        if (errp && *errp) {
            goto out;
        }

        if (ranges_overlap(dimm->addr, dimm_size, new_addr, size)) {
            if (hint) {
                DeviceState *d = DEVICE(dimm);
                error_setg(errp, "address range conflicts with '%s'", d->id);
                goto out;
            }
            new_addr = QEMU_ALIGN_UP(dimm->addr + dimm_size, align);
        }
    }
    ret = new_addr;

    if (new_addr < address_space_start) {
        error_setg(errp, "can't add memory [0x%" PRIx64 ":0x%" PRIx64
                   "] at 0x%" PRIx64, new_addr, size, address_space_start);
    } else if ((new_addr + size) > address_space_end) {
        error_setg(errp, "can't add memory [0x%" PRIx64 ":0x%" PRIx64
                   "] beyond 0x%" PRIx64, new_addr, size, address_space_end);
    }

out:
    g_slist_free(list);
    return ret;
}

static Property pc_dimm_properties[] = {
    DEFINE_PROP_UINT64(PC_DIMM_ADDR_PROP, PCDIMMDevice, addr, 0),
    DEFINE_PROP_UINT32(PC_DIMM_NODE_PROP, PCDIMMDevice, node, 0),
    DEFINE_PROP_INT32(PC_DIMM_SLOT_PROP, PCDIMMDevice, slot,
                      PC_DIMM_UNASSIGNED_SLOT),
    DEFINE_PROP_LINK(PC_DIMM_MEMDEV_PROP, PCDIMMDevice, hostmem,
                     TYPE_MEMORY_BACKEND, HostMemoryBackend *),
    DEFINE_PROP_END_OF_LIST(),
};

static void pc_dimm_get_size(Object *obj, Visitor *v, const char *name,
                             void *opaque, Error **errp)
{
    uint64_t value;
    MemoryRegion *mr;
    PCDIMMDevice *dimm = PC_DIMM(obj);
    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(obj);

    mr = ddc->get_memory_region(dimm, errp);
    if (!mr) {
        return;
    }
    value = memory_region_size(mr);

    visit_type_uint64(v, name, &value, errp);
}

static void pc_dimm_init(Object *obj)
{
    object_property_add(obj, PC_DIMM_SIZE_PROP, "uint64", pc_dimm_get_size,
                        NULL, NULL, NULL, &error_abort);
}

static void pc_dimm_realize(DeviceState *dev, Error **errp)
{
    PCDIMMDevice *dimm = PC_DIMM(dev);
    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);

    if (!dimm->hostmem) {
        error_setg(errp, "'" PC_DIMM_MEMDEV_PROP "' property is not set");
        return;
    } else if (host_memory_backend_is_mapped(dimm->hostmem)) {
        char *path = object_get_canonical_path_component(OBJECT(dimm->hostmem));
        error_setg(errp, "can't use already busy memdev: %s", path);
        g_free(path);
        return;
    }
    if (((nb_numa_nodes > 0) && (dimm->node >= nb_numa_nodes)) ||
        (!nb_numa_nodes && dimm->node)) {
        error_setg(errp, "'DIMM property " PC_DIMM_NODE_PROP " has value %"
                   PRIu32 "' which exceeds the number of numa nodes: %d",
                   dimm->node, nb_numa_nodes ? nb_numa_nodes : 1);
        return;
    }

    if (ddc->realize) {
        ddc->realize(dimm, errp);
    }

    host_memory_backend_set_mapped(dimm->hostmem, true);
}

static void pc_dimm_unrealize(DeviceState *dev, Error **errp)
{
    PCDIMMDevice *dimm = PC_DIMM(dev);

    host_memory_backend_set_mapped(dimm->hostmem, false);
}

static MemoryRegion *pc_dimm_get_memory_region(PCDIMMDevice *dimm, Error **errp)
{
    if (!dimm->hostmem) {
        error_setg(errp, "'" PC_DIMM_MEMDEV_PROP "' property must be set");
        return NULL;
    }

    return host_memory_backend_get_memory(dimm->hostmem, errp);
}

static MemoryRegion *pc_dimm_get_vmstate_memory_region(PCDIMMDevice *dimm)
{
    return host_memory_backend_get_memory(dimm->hostmem, &error_abort);
}

static void pc_dimm_class_init(ObjectClass *oc, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(oc);
    PCDIMMDeviceClass *ddc = PC_DIMM_CLASS(oc);

    dc->realize = pc_dimm_realize;
    dc->unrealize = pc_dimm_unrealize;
    dc->props = pc_dimm_properties;
    dc->desc = "DIMM memory module";

    ddc->get_memory_region = pc_dimm_get_memory_region;
    ddc->get_vmstate_memory_region = pc_dimm_get_vmstate_memory_region;
}

static TypeInfo pc_dimm_info = {
    .name          = TYPE_PC_DIMM,
    .parent        = TYPE_DEVICE,
    .instance_size = sizeof(PCDIMMDevice),
    .instance_init = pc_dimm_init,
    .class_init    = pc_dimm_class_init,
    .class_size    = sizeof(PCDIMMDeviceClass),
};

static void pc_dimm_register_types(void)
{
    type_register_static(&pc_dimm_info);
}

type_init(pc_dimm_register_types)
