Re: [Qemu-devel] [RFC PATCH v2 06/21] dimm: Implement memory device abstraction

[Blue Swirl]

On Wed, Jul 11, 2012 at 10:31 AM, Vasilis Liaskovitis
<address@hidden> wrote:
> Each hotplug-able memory slot is a SysBusDevice. A hot-add operation for a
> particular dimm creates a new MemoryRegion of the given physical address
> offset, size and node proximity, and attaches it to main system memory as a
> sub_region. A hot-remove operation detaches and frees the MemoryRegion from
> system memory.
>
> This prototype still lacks proper qdev integration: a separate
> hotplug side-channel is used and main system bus hotplug capability is
> ignored.
>
> Signed-off-by: Vasilis Liaskovitis <address@hidden>
> ---
>  hw/Makefile.objs |    2 +-
>  hw/dimm.c        |  234 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/dimm.h        |   58 +++++++++++++
>  3 files changed, 293 insertions(+), 1 deletions(-)
>  create mode 100644 hw/dimm.c
>  create mode 100644 hw/dimm.h
>
> diff --git a/hw/Makefile.objs b/hw/Makefile.objs
> index 3d77259..e2184bf 100644
> --- a/hw/Makefile.objs
> +++ b/hw/Makefile.objs
> @@ -26,7 +26,7 @@ hw-obj-$(CONFIG_I8254) += i8254_common.o i8254.o
>  hw-obj-$(CONFIG_PCSPK) += pcspk.o
>  hw-obj-$(CONFIG_PCKBD) += pckbd.o
>  hw-obj-$(CONFIG_FDC) += fdc.o
> -hw-obj-$(CONFIG_ACPI) += acpi.o acpi_piix4.o
> +hw-obj-$(CONFIG_ACPI) += acpi.o acpi_piix4.o dimm.o
>  hw-obj-$(CONFIG_APM) += pm_smbus.o apm.o
>  hw-obj-$(CONFIG_DMA) += dma.o
>  hw-obj-$(CONFIG_I82374) += i82374.o
> diff --git a/hw/dimm.c b/hw/dimm.c
> new file mode 100644
> index 0000000..00c4623
> --- /dev/null
> +++ b/hw/dimm.c
> @@ -0,0 +1,234 @@
> +/*
> + * Dimm device for Memory Hotplug
> + *
> + * Copyright ProfitBricks GmbH 2012
> + * 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 "trace.h"
> +#include "qdev.h"
> +#include "dimm.h"
> +#include <time.h>
> +#include "../exec-memory.h"
> +#include "qmp-commands.h"
> +
> +static DeviceState *dimm_hotplug_qdev;
> +static dimm_hotplug_fn dimm_hotplug;
> +static QTAILQ_HEAD(Dimmlist, DimmState)  dimmlist;

Using global state does not look right. It should always be possible
to pass around structures to avoid it.

> +
> +static Property dimm_properties[] = {
> +    DEFINE_PROP_END_OF_LIST()
> +};
> +
> +void dimm_populate(DimmState *s)

All functions are global and exported but there does not seem to be
users. Please make all static which you can.

> +{
> +    DeviceState *dev= (DeviceState*)s;
> +    MemoryRegion *new = NULL;
> +
> +    new = g_malloc(sizeof(MemoryRegion));
> +    memory_region_init_ram(new, dev->id, s->size);
> +    vmstate_register_ram_global(new);
> +    memory_region_add_subregion(get_system_memory(), s->start, new);
> +    s->mr = new;
> +    s->populated = true;
> +}
> +
> +
> +void dimm_depopulate(DimmState *s)
> +{
> +    assert(s);
> +    if (s->populated) {
> +        vmstate_unregister_ram(s->mr, NULL);
> +        memory_region_del_subregion(get_system_memory(), s->mr);
> +        memory_region_destroy(s->mr);
> +        s->populated = false;
> +        s->mr = NULL;
> +    }
> +}
> +
> +DimmState *dimm_create(char *id, uint64_t size, uint64_t node, uint32_t
> +        dimm_idx, bool populated)
> +{
> +    DeviceState *dev;
> +    DimmState *mdev;
> +
> +    dev = sysbus_create_simple("dimm", -1, NULL);
> +    dev->id = id;
> +
> +    mdev = DIMM(dev);
> +    mdev->idx = dimm_idx;
> +    mdev->start = 0;
> +    mdev->size = size;
> +    mdev->node = node;
> +    mdev->populated = populated;
> +    QTAILQ_INSERT_TAIL(&dimmlist, mdev, nextdimm);
> +    return mdev;
> +}
> +
> +void dimm_register_hotplug(dimm_hotplug_fn hotplug, DeviceState *qdev)
> +{
> +    dimm_hotplug_qdev = qdev;
> +    dimm_hotplug = hotplug;
> +    dimm_scan_populated();
> +}
> +
> +void dimm_activate(DimmState *slot)
> +{
> +    dimm_populate(slot);
> +    if (dimm_hotplug)
> +        dimm_hotplug(dimm_hotplug_qdev, (SysBusDevice*)slot, 1);

Why the cast?

Also braces, please check your patches with checkpatch.pl.

> +}
> +
> +void dimm_deactivate(DimmState *slot)
> +{
> +    if (dimm_hotplug)
> +        dimm_hotplug(dimm_hotplug_qdev, (SysBusDevice*)slot, 0);
> +}
> +
> +DimmState *dimm_find_from_name(char *id)

const char *id?

> +{
> +    Error *err = NULL;
> +    DeviceState *qdev;
> +    const char *type;
> +    qdev = qdev_find_recursive(sysbus_get_default(), id);
> +    if (qdev) {
> +        type = object_property_get_str(OBJECT(qdev), "type", &err);
> +        if (!type) {
> +            return NULL;
> +        }
> +        if (!strcmp(type, "dimm")) {
> +            return DIMM(qdev);
> +        }
> +    }
> +    return NULL;
> +}
> +
> +int dimm_do(Monitor *mon, const QDict *qdict, bool add)
> +{
> +    DimmState *slot = NULL;
> +
> +    char *id = (char*) qdict_get_try_str(qdict, "id");

Why this cast?

> +    if (!id) {
> +        fprintf(stderr, "ERROR %s invalid id\n",__FUNCTION__);
> +        return 1;
> +    }
> +
> +    slot = dimm_find_from_name(id);
> +
> +    if (!slot) {
> +        fprintf(stderr, "%s no slot %s found\n", __FUNCTION__, id);
> +        return 1;
> +    }
> +
> +    if (add) {
> +        if (slot->populated) {
> +            fprintf(stderr, "ERROR %s slot %s already populated\n",
> +                    __FUNCTION__, id);
> +            return 1;
> +        }
> +        dimm_activate(slot);
> +    }
> +    else {
> +        if (!slot->populated) {
> +            fprintf(stderr, "ERROR %s slot %s is not populated\n",
> +                    __FUNCTION__, id);
> +            return 1;
> +        }
> +        dimm_deactivate(slot);
> +    }
> +
> +    return 0;
> +}
> +
> +DimmState *dimm_find_from_idx(uint32_t idx)
> +{
> +    DimmState *slot;
> +
> +    QTAILQ_FOREACH(slot, &dimmlist, nextdimm) {
> +        if (slot->idx == idx) {
> +            return slot;
> +        }
> +    }
> +    return NULL;
> +}
> +
> +/* used to calculate physical address offsets for all dimms */
> +void dimm_calc_offsets(dimm_calcoffset_fn calcfn)
> +{
> +    DimmState *slot;
> +    QTAILQ_FOREACH(slot, &dimmlist, nextdimm) {
> +        if (!slot->start)
> +            slot->start = calcfn(slot->size);
> +    }
> +}
> +
> +/* used to populate and activate dimms at boot time */
> +void dimm_scan_populated(void)
> +{
> +    DimmState *slot;
> +    QTAILQ_FOREACH(slot, &dimmlist, nextdimm) {
> +        if (slot->populated && !slot->mr) {
> +            dimm_activate(slot);
> +        }
> +    }
> +}
> +
> +void dimm_notify(uint32_t idx, uint32_t event)
> +{
> +    DimmState *s;
> +    s = dimm_find_from_idx(idx);
> +    assert(s != NULL);
> +
> +    switch(event) {
> +        case DIMM_REMOVE_SUCCESS:
> +            dimm_depopulate(s);
> +            break;
> +        default:
> +            break;
> +    }
> +}
> +
> +static int dimm_init(SysBusDevice *s)
> +{
> +    DimmState *slot;
> +    slot = DIMM(s);
> +    slot->mr = NULL;
> +    slot->populated = false;
> +    return 0;
> +}
> +
> +static void dimm_class_init(ObjectClass *klass, void *data)
> +{
> +    SysBusDeviceClass *sc = SYS_BUS_DEVICE_CLASS(klass);
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->props = dimm_properties;
> +    sc->init = dimm_init;
> +    dimm_hotplug = NULL;
> +    QTAILQ_INIT(&dimmlist);
> +}
> +
> +static TypeInfo dimm_info = {
> +    .name          = "dimm",
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(DimmState),
> +    .class_init    = dimm_class_init,
> +};
> +
> +static void dimm_register_types(void)
> +{
> +    type_register_static(&dimm_info);
> +}
> +
> +type_init(dimm_register_types)
> diff --git a/hw/dimm.h b/hw/dimm.h
> new file mode 100644
> index 0000000..643f319
> --- /dev/null
> +++ b/hw/dimm.h
> @@ -0,0 +1,58 @@
> +#ifndef QEMU_DIMM_H
> +#define QEMU_DIMM_H

Should be HW_DIMM_H.

> +
> +#include "qemu-common.h"
> +#include "memory.h"
> +#include "sysbus.h"
> +#include "qapi-types.h"
> +#include "qemu-queue.h"
> +#include "cpus.h"
> +#define MAX_DIMMS 255
> +#define DIMM_BITMAP_BYTES (MAX_DIMMS + 7) / 8
> +#define DEFAULT_DIMMSIZE 1024*1024*1024
> +
> +typedef enum {
> +    DIMM_REMOVE_SUCCESS = 0,
> +    DIMM_REMOVE_FAIL = 1,
> +    DIMM_ADD_SUCCESS = 2,
> +    DIMM_ADD_FAIL = 3
> +} dimm_hp_result_code;
> +
> +#define TYPE_DIMM "dimm"
> +#define DIMM(obj) \
> +    OBJECT_CHECK(DimmState, (obj), TYPE_DIMM)
> +#define DIMM_CLASS(klass) \
> +    OBJECT_CLASS_CHECK(DimmClass, (obj), TYPE_DIMM)
> +#define DIMM_GET_CLASS(obj) \
> +    OBJECT_GET_CLASS(DimmClass, (obj), TYPE_DIMM)
> +
> +typedef struct DimmState {
> +    SysBusDevice busdev;
> +    uint32_t idx; /* index in memory hotplug register/bitmap */
> +    ram_addr_t start; /* starting physical address */
> +    ram_addr_t size;
> +    uint32_t node; /* numa node proximity */
> +    MemoryRegion *mr; /* MemoryRegion for this slot. !NULL only if populated 
> */
> +    bool populated; /* 1 means device has been hotplugged. Default is 0. */
> +    QTAILQ_ENTRY (DimmState) nextdimm;
> +} DimmState;
> +
> +typedef int (*dimm_hotplug_fn)(DeviceState *qdev, SysBusDevice *dev, int 
> add);
> +typedef target_phys_addr_t (*dimm_calcoffset_fn)(uint64_t size);
> +
> +DimmState *dimm_create(char *id, uint64_t size, uint64_t node, uint32_t
> +        dimm_idx, bool populated);
> +void dimm_populate(DimmState *s);
> +void dimm_depopulate(DimmState *s);
> +int dimm_do(Monitor *mon, const QDict *qdict, bool add);
> +DimmState *dimm_find_from_idx(uint32_t idx);
> +DimmState *dimm_find_from_name(char *id);
> +void dimm_register_hotplug(dimm_hotplug_fn hotplug, DeviceState *qdev);
> +void dimm_calc_offsets(dimm_calcoffset_fn calcfn);
> +void dimm_activate(DimmState *slot);
> +void dimm_deactivate(DimmState *slot);
> +void dimm_scan_populated(void);
> +void dimm_notify(uint32_t idx, uint32_t event);
> +
> +
> +#endif
> --
> 1.7.9
>
>