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

[Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>]

Hi,

On Thu, Jul 12, 2012 at 07:55:42PM +0000, Blue Swirl wrote:
> On Wed, Jul 11, 2012 at 10:31 AM, Vasilis Liaskovitis
> <vasilis.liaskovitis@profitbricks.com> 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 <vasilis.liaskovitis@profitbricks.com>
> > ---
> >  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.

ok, I 'll try to remove the global state.

> 
> > +
> > +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.

will do

> 
> > +{
> > +    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?

dimm_hotplug accepts SysBusDevice, not DimmState, though that can be changed.
> 
> Also braces, please check your patches with checkpatch.pl.
>

ok, I 'll do checks 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?
ok
> 
> > +{
> > +    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?

unneeded, because id should be declared as const char*. will fix.

> 
> > +    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.
ok.

> 
> > +
> > +#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
> >
> >