diff mbox series

[PATCH-for-4.2,v7,03/10] hw/acpi: Add ACPI Generic Event Device Support

Message ID 20190716153816.17676-4-shameerali.kolothum.thodi@huawei.com (mailing list archive)
State New, archived
Headers show
Series ARM virt: ACPI memory hotplug support | expand

Commit Message

Shameerali Kolothum Thodi July 16, 2019, 3:38 p.m. UTC
From: Samuel Ortiz <sameo@linux.intel.com>

The ACPI Generic Event Device (GED) is a hardware-reduced specific
device[ACPI v6.1 Section 5.6.9] that handles all platform events,
including the hotplug ones. This patch generates the AML code that
defines GEDs.

Platforms need to specify their own GED Event bitmap to describe
what kind of events they want to support through GED.  Also this
uses a a single interrupt for the  GED device, relying on IO
memory region to communicate the type of device affected by the
interrupt. This way, we can support up to 32 events with a unique
interrupt.

This supports only memory hotplug for now.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
---
 hw/acpi/Kconfig                        |   4 +
 hw/acpi/Makefile.objs                  |   1 +
 hw/acpi/generic_event_device.c         | 336 +++++++++++++++++++++++++
 include/hw/acpi/generic_event_device.h | 102 ++++++++
 4 files changed, 443 insertions(+)
 create mode 100644 hw/acpi/generic_event_device.c
 create mode 100644 include/hw/acpi/generic_event_device.h

Comments

Igor Mammedov July 17, 2019, 2:32 p.m. UTC | #1
On Tue, 16 Jul 2019 16:38:09 +0100
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:

> From: Samuel Ortiz <sameo@linux.intel.com>
> 
> The ACPI Generic Event Device (GED) is a hardware-reduced specific
> device[ACPI v6.1 Section 5.6.9] that handles all platform events,
> including the hotplug ones. This patch generates the AML code that
> defines GEDs.
> 
> Platforms need to specify their own GED Event bitmap to describe
> what kind of events they want to support through GED.  Also this
> uses a a single interrupt for the  GED device, relying on IO
> memory region to communicate the type of device affected by the
> interrupt. This way, we can support up to 32 events with a unique
> interrupt.
> 
> This supports only memory hotplug for now.
> 
> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> ---
>  hw/acpi/Kconfig                        |   4 +
>  hw/acpi/Makefile.objs                  |   1 +
>  hw/acpi/generic_event_device.c         | 336 +++++++++++++++++++++++++
>  include/hw/acpi/generic_event_device.h | 102 ++++++++
>  4 files changed, 443 insertions(+)
>  create mode 100644 hw/acpi/generic_event_device.c
>  create mode 100644 include/hw/acpi/generic_event_device.h
> 
> diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
> index 7c59cf900b..12e3f1e86e 100644
> --- a/hw/acpi/Kconfig
> +++ b/hw/acpi/Kconfig
> @@ -31,3 +31,7 @@ config ACPI_VMGENID
>      bool
>      default y
>      depends on PC
> +
> +config ACPI_HW_REDUCED
> +    bool
> +    depends on ACPI
> diff --git a/hw/acpi/Makefile.objs b/hw/acpi/Makefile.objs
> index 9bb2101e3b..655a9c1973 100644
> --- a/hw/acpi/Makefile.objs
> +++ b/hw/acpi/Makefile.objs
> @@ -6,6 +6,7 @@ common-obj-$(CONFIG_ACPI_MEMORY_HOTPLUG) += memory_hotplug.o
>  common-obj-$(CONFIG_ACPI_CPU_HOTPLUG) += cpu.o
>  common-obj-$(CONFIG_ACPI_NVDIMM) += nvdimm.o
>  common-obj-$(CONFIG_ACPI_VMGENID) += vmgenid.o
> +common-obj-$(CONFIG_ACPI_HW_REDUCED) += generic_event_device.o
>  common-obj-$(call lnot,$(CONFIG_ACPI_X86)) += acpi-stub.o
>  
>  common-obj-y += acpi_interface.o
> diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
> new file mode 100644
> index 0000000000..2a83d68e82
> --- /dev/null
> +++ b/hw/acpi/generic_event_device.c
> @@ -0,0 +1,336 @@
> +/*
> + *
> + * Copyright (c) 2018 Intel Corporation
> + * Copyright (c) 2019 Huawei Technologies R & D (UK) Ltd
> + * Written by Samuel Ortiz, Shameer Kolothum
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "exec/address-spaces.h"
> +#include "hw/acpi/acpi.h"
> +#include "hw/acpi/generic_event_device.h"
> +#include "hw/mem/pc-dimm.h"
> +#include "qemu/error-report.h"
> +
> +static const uint32_t ged_supported_events[] = {
> +    ACPI_GED_MEM_HOTPLUG_EVT,
> +};
> +
> +/*
> + * The ACPI Generic Event Device (GED) is a hardware-reduced specific
> + * device[ACPI v6.1 Section 5.6.9] that handles all platform events,
> + * including the hotplug ones. Platforms need to specify their own
> + * GED Event bitmap to describe what kind of events they want to support
> + * through GED. This routine uses a single interrupt for the GED device,
> + * relying on IO memory region to communicate the type of device
> + * affected by the interrupt. This way, we can support up to 32 events
> + * with a unique interrupt.
> + */
> +void build_ged_aml(Aml *table, const char *name, HotplugHandler *hotplug_dev,
> +                   uint32_t ged_irq, AmlRegionSpace rs)
> +{
> +    AcpiGedState *s = ACPI_GED(hotplug_dev);
> +    Aml *crs = aml_resource_template();
> +    Aml *evt, *field;
> +    Aml *dev = aml_device("%s", name);
> +    Aml *evt_sel = aml_local(0);
> +    Aml *esel = aml_name(AML_GED_EVT_SEL);
> +
> +    assert(s->ged_base);
> +
> +    /* _CRS interrupt */
> +    aml_append(crs, aml_interrupt(AML_CONSUMER, AML_EDGE, AML_ACTIVE_HIGH,
> +                                  AML_EXCLUSIVE, &ged_irq, 1));
> +
> +    aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0013")));
> +    aml_append(dev, aml_name_decl("_UID", aml_string(GED_DEVICE)));
> +    aml_append(dev, aml_name_decl("_CRS", crs));
> +
> +    /* Append IO region */
> +    aml_append(dev, aml_operation_region(AML_GED_EVT_REG, rs,
> +               aml_int(s->ged_base + ACPI_GED_EVT_SEL_OFFSET),
> +               ACPI_GED_EVT_SEL_LEN));
> +    field = aml_field(AML_GED_EVT_REG, AML_DWORD_ACC, AML_NOLOCK,
> +                      AML_WRITE_AS_ZEROS);
> +    aml_append(field, aml_named_field(AML_GED_EVT_SEL,
> +                                      ACPI_GED_EVT_SEL_LEN * BITS_PER_BYTE));
> +    aml_append(dev, field);
> +
> +    /*
> +     * For each GED event we:
> +     * - Add a conditional block for each event, inside a loop.
> +     * - Call a method for each supported GED event type.
> +     *
> +     * The resulting ASL code looks like:
> +     *
> +     * Local0 = ESEL
> +     * If ((Local0 & One) == One)
> +     * {
> +     *     MethodEvent0()
> +     * }
> +     *
> +     * If ((Local0 & 0x2) == 0x2)
> +     * {
> +     *     MethodEvent1()
> +     * }
> +     * ...
> +     */
> +    evt = aml_method("_EVT", 1, AML_SERIALIZED);
> +    {
> +        Aml *if_ctx;
> +        uint32_t i;
> +        uint32_t ged_events = ctpop32(s->ged_event_bitmap);
> +
> +        /* Local0 = ESEL */
> +        aml_append(evt, aml_store(esel, evt_sel));
> +
> +        for (i = 0; i < ARRAY_SIZE(ged_supported_events) && ged_events; i++) {
> +            uint32_t event = s->ged_event_bitmap & ged_supported_events[i];
> +
> +            if (!event) {
> +                continue;
> +            }
> +
> +            if_ctx = aml_if(aml_equal(aml_and(evt_sel, aml_int(event), NULL),
> +                                      aml_int(event)));
> +            switch (event) {
> +            case ACPI_GED_MEM_HOTPLUG_EVT:
> +                aml_append(if_ctx, aml_call0(MEMORY_DEVICES_CONTAINER "."
> +                                             MEMORY_SLOT_SCAN_METHOD));
> +                break;
> +            default:
> +                /*
> +                 * Please make sure all the events in ged_supported_events[]
> +                 * are handled above.
> +                 */
> +                g_assert_not_reached();
> +            }
> +
> +            aml_append(evt, if_ctx);
> +            ged_events--;
> +        }
> +
> +        if (ged_events) {
> +            error_report("GED: Unsupported events specified");
> +            exit(1);
> +        }
> +    }
> +
> +    /* Append _EVT method */
> +    aml_append(dev, evt);
> +
> +    aml_append(table, dev);
> +}
> +
> +/* Memory read by the GED _EVT AML dynamic method */
> +static uint64_t ged_read(void *opaque, hwaddr addr, unsigned size)
> +{
> +    uint64_t val = 0;
> +    GEDState *ged_st = opaque;
> +
> +    switch (addr) {
> +    case ACPI_GED_EVT_SEL_OFFSET:
> +        /* Read the selector value and reset it */
> +        qemu_mutex_lock(&ged_st->lock);
> +        val = ged_st->sel;
> +        ged_st->sel = 0;
> +        qemu_mutex_unlock(&ged_st->lock);
> +        break;
> +    default:
> +        break;
> +    }
> +
> +    return val;
> +}
> +
> +/* Nothing is expected to be written to the GED memory region */
> +static void ged_write(void *opaque, hwaddr addr, uint64_t data,
> +                      unsigned int size)
> +{
> +}
> +
> +static const MemoryRegionOps ged_ops = {
> +    .read = ged_read,
> +    .write = ged_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .valid = {
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +    },
> +};
> +
> +static void acpi_ged_event(AcpiGedState *s, uint32_t sel)
> +{
> +    GEDState *ged_st = &s->ged_state;
> +    /*
> +     * Set the GED IRQ selector to the expected device type value. This
> +     * way, the ACPI method will be able to trigger the right code based
> +     * on a unique IRQ.
comment isn't correct anymore, pls fix it

> +     */
> +    qemu_mutex_lock(&ged_st->lock);
Is this lock really necessary?
(I thought that MMIO and monitor access is guarded by BQL)

> +    ged_st->sel |= sel;
> +    qemu_mutex_unlock(&ged_st->lock);
> +
> +    /* Trigger the event by sending an interrupt to the guest. */
> +    qemu_irq_pulse(s->irq);
> +}
> +
> +static void acpi_ged_init(MemoryRegion *as, DeviceState *dev, GEDState *ged_st)
> +{
> +    AcpiGedState *s = ACPI_GED(dev);
> +
> +    assert(s->ged_base);
> +
> +    qemu_mutex_init(&ged_st->lock);
> +    memory_region_init_io(&ged_st->io, OBJECT(dev), &ged_ops, ged_st,
> +                          TYPE_ACPI_GED, ACPI_GED_REG_LEN);
> +    memory_region_add_subregion(as, s->ged_base, &ged_st->io);
> +    qdev_init_gpio_out_named(DEVICE(s), &s->irq, "ged-irq", 1);
> +}
> +
> +static void acpi_ged_device_plug_cb(HotplugHandler *hotplug_dev,
> +                                    DeviceState *dev, Error **errp)
> +{
> +    AcpiGedState *s = ACPI_GED(hotplug_dev);
> +
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> +        if (s->memhp_state.is_enabled) {
> +            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state, dev, errp);
> +        } else {
> +            error_setg(errp,
> +                 "memory hotplug is not enabled: %s.memory-hotplug-support "
> +                 "is not set", object_get_typename(OBJECT(s)));
> +        }
> +    } else {
> +        error_setg(errp, "virt: device plug request for unsupported device"
> +                   " type: %s", object_get_typename(OBJECT(dev)));
> +    }
> +}
> +
> +static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
> +{
> +    AcpiGedState *s = ACPI_GED(adev);
> +    uint32_t sel;
> +
> +    if (ev & ACPI_MEMORY_HOTPLUG_STATUS) {
> +        sel = ACPI_GED_MEM_HOTPLUG_EVT;
> +    } else {
> +        /* Unknown event. Return without generating interrupt. */
> +        warn_report("GED: Unsupported event %d. No irq injected", ev);
> +        return;
> +    }
> +
> +    /*
> +     * We inject the hotplug interrupt. The IRQ selector will make
> +     * the difference from the ACPI table.
I don't get comment at all, pls rephrase/

> +     */
> +    acpi_ged_event(s, sel);
it seems to used only once and only here, suggest to drop acpi_ged_event()
and move it's code here.

> +}
> +
> +static void acpi_ged_device_realize(DeviceState *dev, Error **errp)
> +{
> +    AcpiGedState *s = ACPI_GED(dev);
> +
> +    if (s->memhp_state.is_enabled) {
> +        acpi_memory_hotplug_init(get_system_memory(), OBJECT(dev),
> +                                 &s->memhp_state,
> +                                 s->memhp_base);
> +    }
> +
> +    acpi_ged_init(get_system_memory(), dev, &s->ged_state);
> +}
> +
> +static Property acpi_ged_properties[] = {
> +    /*
> +     * Memory hotplug base address is a property of GED here,
> +     * because GED handles memory hotplug event and acpi-mem-hotplug
> +     * memory region gets initialized when GED device is realized.
> +     */
> +    DEFINE_PROP_UINT64("memhp-base", AcpiGedState, memhp_base, 0),
> +    DEFINE_PROP_BOOL("memory-hotplug-support", AcpiGedState,
> +                     memhp_state.is_enabled, true),
> +    DEFINE_PROP_UINT64("ged-base", AcpiGedState, ged_base, 0),

I'd add checks to realize() to ensure that both foo_base are not left
uninitialized (i.e. at default values)

> +    DEFINE_PROP_UINT32("ged-event", AcpiGedState, ged_event_bitmap, 0),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static bool vmstate_test_use_memhp(void *opaque)
> +{
> +    AcpiGedState *s = opaque;
> +    return s->memhp_state.is_enabled;
> +}
> +
> +static const VMStateDescription vmstate_memhp_state = {
> +    .name = "acpi-ged/memhp",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .needed = vmstate_test_use_memhp,
> +    .fields      = (VMStateField[]) {
> +        VMSTATE_MEMORY_HOTPLUG(memhp_state, AcpiGedState),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static const VMStateDescription vmstate_ged_state = {
> +    .name = "acpi-ged-state",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields      = (VMStateField[]) {
> +        VMSTATE_UINT32(sel, GEDState),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static const VMStateDescription vmstate_acpi_ged = {
> +    .name = "acpi-ged",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_STRUCT(ged_state, AcpiGedState, 1, vmstate_ged_state, GEDState),
> +        VMSTATE_END_OF_LIST(),
> +    },
> +    .subsections = (const VMStateDescription * []) {
> +        &vmstate_memhp_state,
> +        NULL
> +    }
> +};
> +
> +static void acpi_ged_class_init(ObjectClass *class, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(class);
> +    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(class);
> +    AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_CLASS(class);
> +
> +    dc->desc = "ACPI Generic Event Device";
> +    dc->props = acpi_ged_properties;
> +    dc->realize = acpi_ged_device_realize;
> +    dc->vmsd = &vmstate_acpi_ged;
> +
> +    hc->plug = acpi_ged_device_plug_cb;
> +
> +    adevc->send_event = acpi_ged_send_event;
> +}
> +
> +static const TypeInfo acpi_ged_info = {
> +    .name          = TYPE_ACPI_GED,
> +    .parent        = TYPE_DEVICE,
> +    .instance_size = sizeof(AcpiGedState),
> +    .class_init    = acpi_ged_class_init,
> +    .interfaces = (InterfaceInfo[]) {
> +        { TYPE_HOTPLUG_HANDLER },
> +        { TYPE_ACPI_DEVICE_IF },
> +        { }
> +    }
> +};
> +
> +static void acpi_ged_register_types(void)
> +{
> +    type_register_static(&acpi_ged_info);
> +}
> +
> +type_init(acpi_ged_register_types)
> diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
> new file mode 100644
> index 0000000000..f69d084c89
> --- /dev/null
> +++ b/include/hw/acpi/generic_event_device.h
> @@ -0,0 +1,102 @@
> +/*
> + *
> + * Copyright (c) 2018 Intel Corporation
> + * Copyright (c) 2019 Huawei Technologies R & D (UK) Ltd
> + * Written by Samuel Ortiz, Shameer Kolothum
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * The ACPI Generic Event Device (GED) is a hardware-reduced specific
> + * device[ACPI v6.1 Section 5.6.9] that handles all platform events,
> + * including the hotplug ones. Generic Event Device allows platforms
> + * to handle interrupts in ACPI ASL statements. It follows a very
> + * similar approach like the _EVT method from GPIO events. All
> + * interrupts are listed in  _CRS and the handler is written in _EVT
> + * method. Here, we use a single interrupt for the GED device, relying
> + * on IO memory region to communicate the type of device affected by
> + * the interrupt. This way, we can support up to 32 events with a
> + * unique interrupt.
> + *
> + * Here is an example.
> + *
> + * Device (\_SB.GED)
> + * {
> + *     Name (_HID, "ACPI0013")
> + *     Name (_UID, Zero)
> + *     Name (_CRS, ResourceTemplate ()
> + *     {
> + *         Interrupt (ResourceConsumer, Edge, ActiveHigh, Exclusive, ,, )
> + *         {
> + *              0x00000029,
> + *         }
> + *     })
> + *     OperationRegion (EREG, SystemMemory, 0x09080000, 0x04)
> + *     Field (EREG, DWordAcc, NoLock, WriteAsZeros)
> + *     {
> + *         ESEL,   32
> + *     }
> + *
> + *     Method (_EVT, 1, Serialized)  // _EVT: Event
> + *     {
> + *         Local0 = ESEL // ESEL = IO memory region which specifies the
> + *                       // device type.
> + *         If (((Local0 & One) == One))
> + *         {
> + *             MethodEvent1()
> + *         }
> + *         If ((Local0 & 0x2) == 0x2)
> + *         {
> + *             MethodEvent2()
> + *         }
> + *         ...
> + *     }
> + * }
> + *
> + */
> +
> +#ifndef HW_ACPI_GED_H
> +#define HW_ACPI_GED_H
> +
> +#include "hw/acpi/memory_hotplug.h"
> +
> +#define TYPE_ACPI_GED "acpi-ged"
> +#define ACPI_GED(obj) \
> +    OBJECT_CHECK(AcpiGedState, (obj), TYPE_ACPI_GED)
> +
> +#define ACPI_GED_EVT_SEL_OFFSET    0x0

> +#define ACPI_GED_EVT_SEL_LEN       0x4
> +#define ACPI_GED_REG_LEN           0x4
Didn't both macros refer to the same thing?
Why not use the same one in AML and in QEMU MMIO handler?


> +
> +#define GED_DEVICE      "GED"
> +#define AML_GED_EVT_REG "EREG"
> +#define AML_GED_EVT_SEL "ESEL"
> +
> +/*
> + * Platforms need to specify the GED event bitmap
> + * to describe what kind of events they want to support
> + * through GED.
> + */
> +#define ACPI_GED_MEM_HOTPLUG_EVT   0x1
> +
> +typedef struct GEDState {
> +    MemoryRegion io;
> +    uint32_t     sel;
> +    QemuMutex    lock;
> +} GEDState;
> +
> +typedef struct AcpiGedState {
> +    DeviceClass parent_obj;
> +    MemHotplugState memhp_state;
> +    hwaddr memhp_base;
> +    hwaddr ged_base;
> +    GEDState ged_state;
> +    uint32_t ged_event_bitmap;
> +    qemu_irq irq;
> +} AcpiGedState;
> +
> +void build_ged_aml(Aml *table, const char* name, HotplugHandler *hotplug_dev,
> +                   uint32_t ged_irq, AmlRegionSpace rs);
> +
> +#endif
Shameerali Kolothum Thodi July 18, 2019, 10:52 a.m. UTC | #2
Hi Igor,

> -----Original Message-----
> From: Qemu-devel
> [mailto:qemu-devel-bounces+shameerali.kolothum.thodi=huawei.com@nongn
> u.org] On Behalf Of Igor Mammedov
> Sent: 17 July 2019 15:33
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> Cc: peter.maydell@linaro.org; sameo@linux.intel.com;
> shannon.zhaosl@gmail.com; ard.biesheuvel@linaro.org;
> qemu-devel@nongnu.org; xuwei (O) <xuwei5@huawei.com>; Linuxarm
> <linuxarm@huawei.com>; eric.auger@redhat.com; qemu-arm@nongnu.org;
> sebastien.boeuf@intel.com; lersek@redhat.com
> Subject: Re: [Qemu-devel] [PATCH-for-4.2 v7 03/10] hw/acpi: Add ACPI Generic
> Event Device Support
> 
> On Tue, 16 Jul 2019 16:38:09 +0100
> Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:

[...]

> > +static void acpi_ged_event(AcpiGedState *s, uint32_t sel)
> > +{
> > +    GEDState *ged_st = &s->ged_state;
> > +    /*
> > +     * Set the GED IRQ selector to the expected device type value. This
> > +     * way, the ACPI method will be able to trigger the right code based
> > +     * on a unique IRQ.
> comment isn't correct anymore, pls fix it

True.

> 
> > +     */
> > +    qemu_mutex_lock(&ged_st->lock);
> Is this lock really necessary?
> (I thought that MMIO and monitor access is guarded by BQL)

Hmm..I am not sure. This is to synchronize with the ged_st->sel update inside
ged_read(). And also acpi_ged_event() gets called through _power_down_notifier()
as well. BQL guard is in place for all the paths here? 

> 
> > +    ged_st->sel |= sel;
> > +    qemu_mutex_unlock(&ged_st->lock);
> > +
> > +    /* Trigger the event by sending an interrupt to the guest. */
> > +    qemu_irq_pulse(s->irq);
> > +}
> > +
> > +static void acpi_ged_init(MemoryRegion *as, DeviceState *dev, GEDState
> *ged_st)
> > +{
> > +    AcpiGedState *s = ACPI_GED(dev);
> > +
> > +    assert(s->ged_base);
> > +
> > +    qemu_mutex_init(&ged_st->lock);
> > +    memory_region_init_io(&ged_st->io, OBJECT(dev), &ged_ops, ged_st,
> > +                          TYPE_ACPI_GED, ACPI_GED_REG_LEN);
> > +    memory_region_add_subregion(as, s->ged_base, &ged_st->io);
> > +    qdev_init_gpio_out_named(DEVICE(s), &s->irq, "ged-irq", 1);
> > +}
> > +
> > +static void acpi_ged_device_plug_cb(HotplugHandler *hotplug_dev,
> > +                                    DeviceState *dev, Error **errp)
> > +{
> > +    AcpiGedState *s = ACPI_GED(hotplug_dev);
> > +
> > +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> > +        if (s->memhp_state.is_enabled) {
> > +            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state, dev,
> errp);
> > +        } else {
> > +            error_setg(errp,
> > +                 "memory hotplug is not
> enabled: %s.memory-hotplug-support "
> > +                 "is not set", object_get_typename(OBJECT(s)));
> > +        }
> > +    } else {
> > +        error_setg(errp, "virt: device plug request for unsupported
> device"
> > +                   " type: %s", object_get_typename(OBJECT(dev)));
> > +    }
> > +}
> > +
> > +static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits
> ev)
> > +{
> > +    AcpiGedState *s = ACPI_GED(adev);
> > +    uint32_t sel;
> > +
> > +    if (ev & ACPI_MEMORY_HOTPLUG_STATUS) {
> > +        sel = ACPI_GED_MEM_HOTPLUG_EVT;
> > +    } else {
> > +        /* Unknown event. Return without generating interrupt. */
> > +        warn_report("GED: Unsupported event %d. No irq injected", ev);
> > +        return;
> > +    }
> > +
> > +    /*
> > +     * We inject the hotplug interrupt. The IRQ selector will make
> > +     * the difference from the ACPI table.
> I don't get comment at all, pls rephrase/

Ok. I think better to get rid of this comment here and update the one in acpi_ged_event()
appropriately.

> 
> > +     */
> > +    acpi_ged_event(s, sel);
> it seems to used only once and only here, suggest to drop acpi_ged_event()
> and move it's code here.

But patch #10 makes use of it from acpi_ged_pm_powerdown_req().

> > +}
> > +
> > +static void acpi_ged_device_realize(DeviceState *dev, Error **errp)
> > +{
> > +    AcpiGedState *s = ACPI_GED(dev);
> > +
> > +    if (s->memhp_state.is_enabled) {
> > +        acpi_memory_hotplug_init(get_system_memory(), OBJECT(dev),
> > +                                 &s->memhp_state,
> > +                                 s->memhp_base);
> > +    }
> > +
> > +    acpi_ged_init(get_system_memory(), dev, &s->ged_state);
> > +}
> > +
> > +static Property acpi_ged_properties[] = {
> > +    /*
> > +     * Memory hotplug base address is a property of GED here,
> > +     * because GED handles memory hotplug event and acpi-mem-hotplug
> > +     * memory region gets initialized when GED device is realized.
> > +     */
> > +    DEFINE_PROP_UINT64("memhp-base", AcpiGedState, memhp_base,
> 0),
> > +    DEFINE_PROP_BOOL("memory-hotplug-support", AcpiGedState,
> > +                     memhp_state.is_enabled, true),
> > +    DEFINE_PROP_UINT64("ged-base", AcpiGedState, ged_base, 0),
> 
> I'd add checks to realize() to ensure that both foo_base are not left
> uninitialized (i.e. at default values)

Ok. ged_base has a check in acpi_ged_init(). I will add check for memhp_base
and move the ged_base one to realize().

> 
> > +    DEFINE_PROP_UINT32("ged-event", AcpiGedState, ged_event_bitmap,
> 0),
> > +    DEFINE_PROP_END_OF_LIST(),
> > +};
> > +
> > +static bool vmstate_test_use_memhp(void *opaque)
> > +{
> > +    AcpiGedState *s = opaque;
> > +    return s->memhp_state.is_enabled;
> > +}
> > +
> > +static const VMStateDescription vmstate_memhp_state = {
> > +    .name = "acpi-ged/memhp",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .needed = vmstate_test_use_memhp,
> > +    .fields      = (VMStateField[]) {
> > +        VMSTATE_MEMORY_HOTPLUG(memhp_state, AcpiGedState),
> > +        VMSTATE_END_OF_LIST()
> > +    }
> > +};
> > +
> > +static const VMStateDescription vmstate_ged_state = {
> > +    .name = "acpi-ged-state",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .fields      = (VMStateField[]) {
> > +        VMSTATE_UINT32(sel, GEDState),
> > +        VMSTATE_END_OF_LIST()
> > +    }
> > +};
> > +
> > +static const VMStateDescription vmstate_acpi_ged = {
> > +    .name = "acpi-ged",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_STRUCT(ged_state, AcpiGedState, 1,
> vmstate_ged_state, GEDState),
> > +        VMSTATE_END_OF_LIST(),
> > +    },
> > +    .subsections = (const VMStateDescription * []) {
> > +        &vmstate_memhp_state,
> > +        NULL
> > +    }
> > +};
> > +
> > +static void acpi_ged_class_init(ObjectClass *class, void *data)
> > +{
> > +    DeviceClass *dc = DEVICE_CLASS(class);
> > +    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(class);
> > +    AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_CLASS(class);
> > +
> > +    dc->desc = "ACPI Generic Event Device";
> > +    dc->props = acpi_ged_properties;
> > +    dc->realize = acpi_ged_device_realize;
> > +    dc->vmsd = &vmstate_acpi_ged;
> > +
> > +    hc->plug = acpi_ged_device_plug_cb;
> > +
> > +    adevc->send_event = acpi_ged_send_event;
> > +}
> > +
> > +static const TypeInfo acpi_ged_info = {
> > +    .name          = TYPE_ACPI_GED,
> > +    .parent        = TYPE_DEVICE,
> > +    .instance_size = sizeof(AcpiGedState),
> > +    .class_init    = acpi_ged_class_init,
> > +    .interfaces = (InterfaceInfo[]) {
> > +        { TYPE_HOTPLUG_HANDLER },
> > +        { TYPE_ACPI_DEVICE_IF },
> > +        { }
> > +    }
> > +};
> > +
> > +static void acpi_ged_register_types(void)
> > +{
> > +    type_register_static(&acpi_ged_info);
> > +}
> > +
> > +type_init(acpi_ged_register_types)
> > diff --git a/include/hw/acpi/generic_event_device.h
> b/include/hw/acpi/generic_event_device.h
> > new file mode 100644
> > index 0000000000..f69d084c89
> > --- /dev/null
> > +++ b/include/hw/acpi/generic_event_device.h
> > @@ -0,0 +1,102 @@
> > +/*
> > + *
> > + * Copyright (c) 2018 Intel Corporation
> > + * Copyright (c) 2019 Huawei Technologies R & D (UK) Ltd
> > + * Written by Samuel Ortiz, Shameer Kolothum
> > + *
> > + * This program is free software; you can redistribute it and/or modify it
> > + * under the terms and conditions of the GNU General Public License,
> > + * version 2 or later, as published by the Free Software Foundation.
> > + *
> > + * The ACPI Generic Event Device (GED) is a hardware-reduced specific
> > + * device[ACPI v6.1 Section 5.6.9] that handles all platform events,
> > + * including the hotplug ones. Generic Event Device allows platforms
> > + * to handle interrupts in ACPI ASL statements. It follows a very
> > + * similar approach like the _EVT method from GPIO events. All
> > + * interrupts are listed in  _CRS and the handler is written in _EVT
> > + * method. Here, we use a single interrupt for the GED device, relying
> > + * on IO memory region to communicate the type of device affected by
> > + * the interrupt. This way, we can support up to 32 events with a
> > + * unique interrupt.
> > + *
> > + * Here is an example.
> > + *
> > + * Device (\_SB.GED)
> > + * {
> > + *     Name (_HID, "ACPI0013")
> > + *     Name (_UID, Zero)
> > + *     Name (_CRS, ResourceTemplate ()
> > + *     {
> > + *         Interrupt (ResourceConsumer, Edge, ActiveHigh, Exclusive, ,, )
> > + *         {
> > + *              0x00000029,
> > + *         }
> > + *     })
> > + *     OperationRegion (EREG, SystemMemory, 0x09080000, 0x04)
> > + *     Field (EREG, DWordAcc, NoLock, WriteAsZeros)
> > + *     {
> > + *         ESEL,   32
> > + *     }
> > + *
> > + *     Method (_EVT, 1, Serialized)  // _EVT: Event
> > + *     {
> > + *         Local0 = ESEL // ESEL = IO memory region which specifies the
> > + *                       // device type.
> > + *         If (((Local0 & One) == One))
> > + *         {
> > + *             MethodEvent1()
> > + *         }
> > + *         If ((Local0 & 0x2) == 0x2)
> > + *         {
> > + *             MethodEvent2()
> > + *         }
> > + *         ...
> > + *     }
> > + * }
> > + *
> > + */
> > +
> > +#ifndef HW_ACPI_GED_H
> > +#define HW_ACPI_GED_H
> > +
> > +#include "hw/acpi/memory_hotplug.h"
> > +
> > +#define TYPE_ACPI_GED "acpi-ged"
> > +#define ACPI_GED(obj) \
> > +    OBJECT_CHECK(AcpiGedState, (obj), TYPE_ACPI_GED)
> > +
> > +#define ACPI_GED_EVT_SEL_OFFSET    0x0
> 
> > +#define ACPI_GED_EVT_SEL_LEN       0x4
> > +#define ACPI_GED_REG_LEN           0x4
> Didn't both macros refer to the same thing?
> Why not use the same one in AML and in QEMU MMIO handler?

Ok.

Thanks,
Shameer

> 
> > +
> > +#define GED_DEVICE      "GED"
> > +#define AML_GED_EVT_REG "EREG"
> > +#define AML_GED_EVT_SEL "ESEL"
> > +
> > +/*
> > + * Platforms need to specify the GED event bitmap
> > + * to describe what kind of events they want to support
> > + * through GED.
> > + */
> > +#define ACPI_GED_MEM_HOTPLUG_EVT   0x1
> > +
> > +typedef struct GEDState {
> > +    MemoryRegion io;
> > +    uint32_t     sel;
> > +    QemuMutex    lock;
> > +} GEDState;
> > +
> > +typedef struct AcpiGedState {
> > +    DeviceClass parent_obj;
> > +    MemHotplugState memhp_state;
> > +    hwaddr memhp_base;
> > +    hwaddr ged_base;
> > +    GEDState ged_state;
> > +    uint32_t ged_event_bitmap;
> > +    qemu_irq irq;
> > +} AcpiGedState;
> > +
> > +void build_ged_aml(Aml *table, const char* name, HotplugHandler
> *hotplug_dev,
> > +                   uint32_t ged_irq, AmlRegionSpace rs);
> > +
> > +#endif
>
Igor Mammedov July 18, 2019, 12:30 p.m. UTC | #3
On Thu, 18 Jul 2019 10:52:10 +0000
Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com> wrote:

> Hi Igor,
> 
> > -----Original Message-----
> > From: Qemu-devel
> > [mailto:qemu-devel-bounces+shameerali.kolothum.thodi=huawei.com@nongn
> > u.org] On Behalf Of Igor Mammedov
> > Sent: 17 July 2019 15:33
> > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> > Cc: peter.maydell@linaro.org; sameo@linux.intel.com;
> > shannon.zhaosl@gmail.com; ard.biesheuvel@linaro.org;
> > qemu-devel@nongnu.org; xuwei (O) <xuwei5@huawei.com>; Linuxarm
> > <linuxarm@huawei.com>; eric.auger@redhat.com; qemu-arm@nongnu.org;
> > sebastien.boeuf@intel.com; lersek@redhat.com
> > Subject: Re: [Qemu-devel] [PATCH-for-4.2 v7 03/10] hw/acpi: Add ACPI Generic
> > Event Device Support
> > 
> > On Tue, 16 Jul 2019 16:38:09 +0100
> > Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:  
> 
> [...]
> 
> > > +static void acpi_ged_event(AcpiGedState *s, uint32_t sel)
> > > +{
> > > +    GEDState *ged_st = &s->ged_state;
> > > +    /*
> > > +     * Set the GED IRQ selector to the expected device type value. This
> > > +     * way, the ACPI method will be able to trigger the right code based
> > > +     * on a unique IRQ.  
> > comment isn't correct anymore, pls fix it  
> 
> True.
> 
> >   
> > > +     */
> > > +    qemu_mutex_lock(&ged_st->lock);  
> > Is this lock really necessary?
> > (I thought that MMIO and monitor access is guarded by BQL)  
> 
> Hmm..I am not sure. This is to synchronize with the ged_st->sel update inside
> ged_read(). And also acpi_ged_event() gets called through _power_down_notifier()
> as well. BQL guard is in place for all the paths here? 
power down command originates from HMP or QMP monitor, so you don't really
need a lock here.

> 
> >   
> > > +    ged_st->sel |= sel;
> > > +    qemu_mutex_unlock(&ged_st->lock);
> > > +
> > > +    /* Trigger the event by sending an interrupt to the guest. */
> > > +    qemu_irq_pulse(s->irq);
> > > +}
> > > +
> > > +static void acpi_ged_init(MemoryRegion *as, DeviceState *dev, GEDState  
> > *ged_st)  
> > > +{
> > > +    AcpiGedState *s = ACPI_GED(dev);
> > > +
> > > +    assert(s->ged_base);
> > > +
> > > +    qemu_mutex_init(&ged_st->lock);
> > > +    memory_region_init_io(&ged_st->io, OBJECT(dev), &ged_ops, ged_st,
> > > +                          TYPE_ACPI_GED, ACPI_GED_REG_LEN);
> > > +    memory_region_add_subregion(as, s->ged_base, &ged_st->io);
> > > +    qdev_init_gpio_out_named(DEVICE(s), &s->irq, "ged-irq", 1);
> > > +}
> > > +
> > > +static void acpi_ged_device_plug_cb(HotplugHandler *hotplug_dev,
> > > +                                    DeviceState *dev, Error **errp)
> > > +{
> > > +    AcpiGedState *s = ACPI_GED(hotplug_dev);
> > > +
> > > +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> > > +        if (s->memhp_state.is_enabled) {
> > > +            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state, dev,  
> > errp);  
> > > +        } else {
> > > +            error_setg(errp,
> > > +                 "memory hotplug is not  
> > enabled: %s.memory-hotplug-support "  
> > > +                 "is not set", object_get_typename(OBJECT(s)));
> > > +        }
> > > +    } else {
> > > +        error_setg(errp, "virt: device plug request for unsupported  
> > device"  
> > > +                   " type: %s", object_get_typename(OBJECT(dev)));
> > > +    }
> > > +}
> > > +
> > > +static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits  
> > ev)  
> > > +{
> > > +    AcpiGedState *s = ACPI_GED(adev);
> > > +    uint32_t sel;
> > > +
> > > +    if (ev & ACPI_MEMORY_HOTPLUG_STATUS) {
> > > +        sel = ACPI_GED_MEM_HOTPLUG_EVT;
> > > +    } else {
> > > +        /* Unknown event. Return without generating interrupt. */
> > > +        warn_report("GED: Unsupported event %d. No irq injected", ev);
> > > +        return;
> > > +    }
> > > +
> > > +    /*
> > > +     * We inject the hotplug interrupt. The IRQ selector will make
> > > +     * the difference from the ACPI table.  
> > I don't get comment at all, pls rephrase/  
> 
> Ok. I think better to get rid of this comment here and update the one in acpi_ged_event()
> appropriately.
> 
> >   
> > > +     */
> > > +    acpi_ged_event(s, sel);  
> > it seems to used only once and only here, suggest to drop acpi_ged_event()
> > and move it's code here.  
> 
> But patch #10 makes use of it from acpi_ged_pm_powerdown_req().
it looks like a valid shortcut but I'd make it follow AcpiInterface->send_event()
path for consistency so only one call chain would exist.


> 
> > > +}
> > > +
> > > +static void acpi_ged_device_realize(DeviceState *dev, Error **errp)
> > > +{
> > > +    AcpiGedState *s = ACPI_GED(dev);
> > > +
> > > +    if (s->memhp_state.is_enabled) {
> > > +        acpi_memory_hotplug_init(get_system_memory(), OBJECT(dev),
> > > +                                 &s->memhp_state,
> > > +                                 s->memhp_base);
> > > +    }
> > > +
> > > +    acpi_ged_init(get_system_memory(), dev, &s->ged_state);
> > > +}
> > > +
> > > +static Property acpi_ged_properties[] = {
> > > +    /*
> > > +     * Memory hotplug base address is a property of GED here,
> > > +     * because GED handles memory hotplug event and acpi-mem-hotplug
> > > +     * memory region gets initialized when GED device is realized.
> > > +     */
> > > +    DEFINE_PROP_UINT64("memhp-base", AcpiGedState, memhp_base,  
> > 0),  
> > > +    DEFINE_PROP_BOOL("memory-hotplug-support", AcpiGedState,
> > > +                     memhp_state.is_enabled, true),
> > > +    DEFINE_PROP_UINT64("ged-base", AcpiGedState, ged_base, 0),  
> > 
> > I'd add checks to realize() to ensure that both foo_base are not left
> > uninitialized (i.e. at default values)  
> 
> Ok. ged_base has a check in acpi_ged_init(). I will add check for memhp_base
> and move the ged_base one to realize().
> 
> >   
> > > +    DEFINE_PROP_UINT32("ged-event", AcpiGedState, ged_event_bitmap,  
> > 0),  
> > > +    DEFINE_PROP_END_OF_LIST(),
> > > +};
> > > +
> > > +static bool vmstate_test_use_memhp(void *opaque)
> > > +{
> > > +    AcpiGedState *s = opaque;
> > > +    return s->memhp_state.is_enabled;
> > > +}
> > > +
> > > +static const VMStateDescription vmstate_memhp_state = {
> > > +    .name = "acpi-ged/memhp",
> > > +    .version_id = 1,
> > > +    .minimum_version_id = 1,
> > > +    .needed = vmstate_test_use_memhp,
> > > +    .fields      = (VMStateField[]) {
> > > +        VMSTATE_MEMORY_HOTPLUG(memhp_state, AcpiGedState),
> > > +        VMSTATE_END_OF_LIST()
> > > +    }
> > > +};
> > > +
> > > +static const VMStateDescription vmstate_ged_state = {
> > > +    .name = "acpi-ged-state",
> > > +    .version_id = 1,
> > > +    .minimum_version_id = 1,
> > > +    .fields      = (VMStateField[]) {
> > > +        VMSTATE_UINT32(sel, GEDState),
> > > +        VMSTATE_END_OF_LIST()
> > > +    }
> > > +};
> > > +
> > > +static const VMStateDescription vmstate_acpi_ged = {
> > > +    .name = "acpi-ged",
> > > +    .version_id = 1,
> > > +    .minimum_version_id = 1,
> > > +    .fields = (VMStateField[]) {
> > > +        VMSTATE_STRUCT(ged_state, AcpiGedState, 1,  
> > vmstate_ged_state, GEDState),  
> > > +        VMSTATE_END_OF_LIST(),
> > > +    },
> > > +    .subsections = (const VMStateDescription * []) {
> > > +        &vmstate_memhp_state,
> > > +        NULL
> > > +    }
> > > +};
> > > +
> > > +static void acpi_ged_class_init(ObjectClass *class, void *data)
> > > +{
> > > +    DeviceClass *dc = DEVICE_CLASS(class);
> > > +    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(class);
> > > +    AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_CLASS(class);
> > > +
> > > +    dc->desc = "ACPI Generic Event Device";
> > > +    dc->props = acpi_ged_properties;
> > > +    dc->realize = acpi_ged_device_realize;
> > > +    dc->vmsd = &vmstate_acpi_ged;
> > > +
> > > +    hc->plug = acpi_ged_device_plug_cb;
> > > +
> > > +    adevc->send_event = acpi_ged_send_event;
> > > +}
> > > +
> > > +static const TypeInfo acpi_ged_info = {
> > > +    .name          = TYPE_ACPI_GED,
> > > +    .parent        = TYPE_DEVICE,
> > > +    .instance_size = sizeof(AcpiGedState),
> > > +    .class_init    = acpi_ged_class_init,
> > > +    .interfaces = (InterfaceInfo[]) {
> > > +        { TYPE_HOTPLUG_HANDLER },
> > > +        { TYPE_ACPI_DEVICE_IF },
> > > +        { }
> > > +    }
> > > +};
> > > +
> > > +static void acpi_ged_register_types(void)
> > > +{
> > > +    type_register_static(&acpi_ged_info);
> > > +}
> > > +
> > > +type_init(acpi_ged_register_types)
> > > diff --git a/include/hw/acpi/generic_event_device.h  
> > b/include/hw/acpi/generic_event_device.h  
> > > new file mode 100644
> > > index 0000000000..f69d084c89
> > > --- /dev/null
> > > +++ b/include/hw/acpi/generic_event_device.h
> > > @@ -0,0 +1,102 @@
> > > +/*
> > > + *
> > > + * Copyright (c) 2018 Intel Corporation
> > > + * Copyright (c) 2019 Huawei Technologies R & D (UK) Ltd
> > > + * Written by Samuel Ortiz, Shameer Kolothum
> > > + *
> > > + * This program is free software; you can redistribute it and/or modify it
> > > + * under the terms and conditions of the GNU General Public License,
> > > + * version 2 or later, as published by the Free Software Foundation.
> > > + *
> > > + * The ACPI Generic Event Device (GED) is a hardware-reduced specific
> > > + * device[ACPI v6.1 Section 5.6.9] that handles all platform events,
> > > + * including the hotplug ones. Generic Event Device allows platforms
> > > + * to handle interrupts in ACPI ASL statements. It follows a very
> > > + * similar approach like the _EVT method from GPIO events. All
> > > + * interrupts are listed in  _CRS and the handler is written in _EVT
> > > + * method. Here, we use a single interrupt for the GED device, relying
> > > + * on IO memory region to communicate the type of device affected by
> > > + * the interrupt. This way, we can support up to 32 events with a
> > > + * unique interrupt.
> > > + *
> > > + * Here is an example.
> > > + *
> > > + * Device (\_SB.GED)
> > > + * {
> > > + *     Name (_HID, "ACPI0013")
> > > + *     Name (_UID, Zero)
> > > + *     Name (_CRS, ResourceTemplate ()
> > > + *     {
> > > + *         Interrupt (ResourceConsumer, Edge, ActiveHigh, Exclusive, ,, )
> > > + *         {
> > > + *              0x00000029,
> > > + *         }
> > > + *     })
> > > + *     OperationRegion (EREG, SystemMemory, 0x09080000, 0x04)
> > > + *     Field (EREG, DWordAcc, NoLock, WriteAsZeros)
> > > + *     {
> > > + *         ESEL,   32
> > > + *     }
> > > + *
> > > + *     Method (_EVT, 1, Serialized)  // _EVT: Event
> > > + *     {
> > > + *         Local0 = ESEL // ESEL = IO memory region which specifies the
> > > + *                       // device type.
> > > + *         If (((Local0 & One) == One))
> > > + *         {
> > > + *             MethodEvent1()
> > > + *         }
> > > + *         If ((Local0 & 0x2) == 0x2)
> > > + *         {
> > > + *             MethodEvent2()
> > > + *         }
> > > + *         ...
> > > + *     }
> > > + * }
> > > + *
> > > + */
> > > +
> > > +#ifndef HW_ACPI_GED_H
> > > +#define HW_ACPI_GED_H
> > > +
> > > +#include "hw/acpi/memory_hotplug.h"
> > > +
> > > +#define TYPE_ACPI_GED "acpi-ged"
> > > +#define ACPI_GED(obj) \
> > > +    OBJECT_CHECK(AcpiGedState, (obj), TYPE_ACPI_GED)
> > > +
> > > +#define ACPI_GED_EVT_SEL_OFFSET    0x0  
> >   
> > > +#define ACPI_GED_EVT_SEL_LEN       0x4
> > > +#define ACPI_GED_REG_LEN           0x4  
> > Didn't both macros refer to the same thing?
> > Why not use the same one in AML and in QEMU MMIO handler?  
> 
> Ok.
> 
> Thanks,
> Shameer
> 
> >   
> > > +
> > > +#define GED_DEVICE      "GED"
> > > +#define AML_GED_EVT_REG "EREG"
> > > +#define AML_GED_EVT_SEL "ESEL"
> > > +
> > > +/*
> > > + * Platforms need to specify the GED event bitmap
> > > + * to describe what kind of events they want to support
> > > + * through GED.
> > > + */
> > > +#define ACPI_GED_MEM_HOTPLUG_EVT   0x1
> > > +
> > > +typedef struct GEDState {
> > > +    MemoryRegion io;
> > > +    uint32_t     sel;
> > > +    QemuMutex    lock;
> > > +} GEDState;
> > > +
> > > +typedef struct AcpiGedState {
> > > +    DeviceClass parent_obj;
> > > +    MemHotplugState memhp_state;
> > > +    hwaddr memhp_base;
> > > +    hwaddr ged_base;
> > > +    GEDState ged_state;
> > > +    uint32_t ged_event_bitmap;
> > > +    qemu_irq irq;
> > > +} AcpiGedState;
> > > +
> > > +void build_ged_aml(Aml *table, const char* name, HotplugHandler  
> > *hotplug_dev,  
> > > +                   uint32_t ged_irq, AmlRegionSpace rs);
> > > +
> > > +#endif  
> >   
>
Shameerali Kolothum Thodi July 22, 2019, 2:13 p.m. UTC | #4
> -----Original Message-----
> From: Igor Mammedov [mailto:imammedo@redhat.com]
> Sent: 18 July 2019 13:31
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> Cc: peter.maydell@linaro.org; sameo@linux.intel.com;
> shannon.zhaosl@gmail.com; ard.biesheuvel@linaro.org;
> qemu-devel@nongnu.org; xuwei (O) <xuwei5@huawei.com>; Linuxarm
> <linuxarm@huawei.com>; eric.auger@redhat.com; qemu-arm@nongnu.org;
> sebastien.boeuf@intel.com; lersek@redhat.com
> Subject: Re: [Qemu-devel] [PATCH-for-4.2 v7 03/10] hw/acpi: Add ACPI Generic
> Event Device Support
> 
> On Thu, 18 Jul 2019 10:52:10 +0000
> Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com> wrote:
> 
> > Hi Igor,
> >
> > > -----Original Message-----
> > > From: Qemu-devel
> > >
> [mailto:qemu-devel-bounces+shameerali.kolothum.thodi=huawei.com@nongn
> > > u.org] On Behalf Of Igor Mammedov
> > > Sent: 17 July 2019 15:33
> > > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> > > Cc: peter.maydell@linaro.org; sameo@linux.intel.com;
> > > shannon.zhaosl@gmail.com; ard.biesheuvel@linaro.org;
> > > qemu-devel@nongnu.org; xuwei (O) <xuwei5@huawei.com>; Linuxarm
> > > <linuxarm@huawei.com>; eric.auger@redhat.com;
> qemu-arm@nongnu.org;
> > > sebastien.boeuf@intel.com; lersek@redhat.com
> > > Subject: Re: [Qemu-devel] [PATCH-for-4.2 v7 03/10] hw/acpi: Add ACPI
> Generic
> > > Event Device Support
> > >
> > > On Tue, 16 Jul 2019 16:38:09 +0100
> > > Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:
> >
> > [...]
> >
> > > > +static void acpi_ged_event(AcpiGedState *s, uint32_t sel)
> > > > +{
> > > > +    GEDState *ged_st = &s->ged_state;
> > > > +    /*
> > > > +     * Set the GED IRQ selector to the expected device type value. This
> > > > +     * way, the ACPI method will be able to trigger the right code based
> > > > +     * on a unique IRQ.
> > > comment isn't correct anymore, pls fix it
> >
> > True.
> >
> > >
> > > > +     */
> > > > +    qemu_mutex_lock(&ged_st->lock);
> > > Is this lock really necessary?
> > > (I thought that MMIO and monitor access is guarded by BQL)
> >
> > Hmm..I am not sure. This is to synchronize with the ged_st->sel update inside
> > ged_read(). And also acpi_ged_event() gets called through
> _power_down_notifier()
> > as well. BQL guard is in place for all the paths here?
> power down command originates from HMP or QMP monitor, so you don't
> really
> need a lock here.

Ok. I will get rid of it then.

> >
> > >
> > > > +    ged_st->sel |= sel;
> > > > +    qemu_mutex_unlock(&ged_st->lock);
> > > > +
> > > > +    /* Trigger the event by sending an interrupt to the guest. */
> > > > +    qemu_irq_pulse(s->irq);
> > > > +}
> > > > +
> > > > +static void acpi_ged_init(MemoryRegion *as, DeviceState *dev,
> GEDState
> > > *ged_st)
> > > > +{
> > > > +    AcpiGedState *s = ACPI_GED(dev);
> > > > +
> > > > +    assert(s->ged_base);
> > > > +
> > > > +    qemu_mutex_init(&ged_st->lock);
> > > > +    memory_region_init_io(&ged_st->io, OBJECT(dev), &ged_ops,
> ged_st,
> > > > +                          TYPE_ACPI_GED, ACPI_GED_REG_LEN);
> > > > +    memory_region_add_subregion(as, s->ged_base, &ged_st->io);
> > > > +    qdev_init_gpio_out_named(DEVICE(s), &s->irq, "ged-irq", 1);
> > > > +}
> > > > +
> > > > +static void acpi_ged_device_plug_cb(HotplugHandler *hotplug_dev,
> > > > +                                    DeviceState *dev, Error
> **errp)
> > > > +{
> > > > +    AcpiGedState *s = ACPI_GED(hotplug_dev);
> > > > +
> > > > +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> > > > +        if (s->memhp_state.is_enabled) {
> > > > +            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state,
> dev,
> > > errp);
> > > > +        } else {
> > > > +            error_setg(errp,
> > > > +                 "memory hotplug is not
> > > enabled: %s.memory-hotplug-support "
> > > > +                 "is not set", object_get_typename(OBJECT(s)));
> > > > +        }
> > > > +    } else {
> > > > +        error_setg(errp, "virt: device plug request for unsupported
> > > device"
> > > > +                   " type: %s",
> object_get_typename(OBJECT(dev)));
> > > > +    }
> > > > +}
> > > > +
> > > > +static void acpi_ged_send_event(AcpiDeviceIf *adev,
> AcpiEventStatusBits
> > > ev)
> > > > +{
> > > > +    AcpiGedState *s = ACPI_GED(adev);
> > > > +    uint32_t sel;
> > > > +
> > > > +    if (ev & ACPI_MEMORY_HOTPLUG_STATUS) {
> > > > +        sel = ACPI_GED_MEM_HOTPLUG_EVT;
> > > > +    } else {
> > > > +        /* Unknown event. Return without generating interrupt. */
> > > > +        warn_report("GED: Unsupported event %d. No irq injected",
> ev);
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    /*
> > > > +     * We inject the hotplug interrupt. The IRQ selector will make
> > > > +     * the difference from the ACPI table.
> > > I don't get comment at all, pls rephrase/
> >
> > Ok. I think better to get rid of this comment here and update the one in
> acpi_ged_event()
> > appropriately.
> >
> > >
> > > > +     */
> > > > +    acpi_ged_event(s, sel);
> > > it seems to used only once and only here, suggest to drop acpi_ged_event()
> > > and move it's code here.
> >
> > But patch #10 makes use of it from acpi_ged_pm_powerdown_req().
> it looks like a valid shortcut but I'd make it follow AcpiInterface->send_event()
> path for consistency so only one call chain would exist.

Agree. 

Thanks,
Shameer
diff mbox series

Patch

diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
index 7c59cf900b..12e3f1e86e 100644
--- a/hw/acpi/Kconfig
+++ b/hw/acpi/Kconfig
@@ -31,3 +31,7 @@  config ACPI_VMGENID
     bool
     default y
     depends on PC
+
+config ACPI_HW_REDUCED
+    bool
+    depends on ACPI
diff --git a/hw/acpi/Makefile.objs b/hw/acpi/Makefile.objs
index 9bb2101e3b..655a9c1973 100644
--- a/hw/acpi/Makefile.objs
+++ b/hw/acpi/Makefile.objs
@@ -6,6 +6,7 @@  common-obj-$(CONFIG_ACPI_MEMORY_HOTPLUG) += memory_hotplug.o
 common-obj-$(CONFIG_ACPI_CPU_HOTPLUG) += cpu.o
 common-obj-$(CONFIG_ACPI_NVDIMM) += nvdimm.o
 common-obj-$(CONFIG_ACPI_VMGENID) += vmgenid.o
+common-obj-$(CONFIG_ACPI_HW_REDUCED) += generic_event_device.o
 common-obj-$(call lnot,$(CONFIG_ACPI_X86)) += acpi-stub.o
 
 common-obj-y += acpi_interface.o
diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
new file mode 100644
index 0000000000..2a83d68e82
--- /dev/null
+++ b/hw/acpi/generic_event_device.c
@@ -0,0 +1,336 @@ 
+/*
+ *
+ * Copyright (c) 2018 Intel Corporation
+ * Copyright (c) 2019 Huawei Technologies R & D (UK) Ltd
+ * Written by Samuel Ortiz, Shameer Kolothum
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "exec/address-spaces.h"
+#include "hw/acpi/acpi.h"
+#include "hw/acpi/generic_event_device.h"
+#include "hw/mem/pc-dimm.h"
+#include "qemu/error-report.h"
+
+static const uint32_t ged_supported_events[] = {
+    ACPI_GED_MEM_HOTPLUG_EVT,
+};
+
+/*
+ * The ACPI Generic Event Device (GED) is a hardware-reduced specific
+ * device[ACPI v6.1 Section 5.6.9] that handles all platform events,
+ * including the hotplug ones. Platforms need to specify their own
+ * GED Event bitmap to describe what kind of events they want to support
+ * through GED. This routine uses a single interrupt for the GED device,
+ * relying on IO memory region to communicate the type of device
+ * affected by the interrupt. This way, we can support up to 32 events
+ * with a unique interrupt.
+ */
+void build_ged_aml(Aml *table, const char *name, HotplugHandler *hotplug_dev,
+                   uint32_t ged_irq, AmlRegionSpace rs)
+{
+    AcpiGedState *s = ACPI_GED(hotplug_dev);
+    Aml *crs = aml_resource_template();
+    Aml *evt, *field;
+    Aml *dev = aml_device("%s", name);
+    Aml *evt_sel = aml_local(0);
+    Aml *esel = aml_name(AML_GED_EVT_SEL);
+
+    assert(s->ged_base);
+
+    /* _CRS interrupt */
+    aml_append(crs, aml_interrupt(AML_CONSUMER, AML_EDGE, AML_ACTIVE_HIGH,
+                                  AML_EXCLUSIVE, &ged_irq, 1));
+
+    aml_append(dev, aml_name_decl("_HID", aml_string("ACPI0013")));
+    aml_append(dev, aml_name_decl("_UID", aml_string(GED_DEVICE)));
+    aml_append(dev, aml_name_decl("_CRS", crs));
+
+    /* Append IO region */
+    aml_append(dev, aml_operation_region(AML_GED_EVT_REG, rs,
+               aml_int(s->ged_base + ACPI_GED_EVT_SEL_OFFSET),
+               ACPI_GED_EVT_SEL_LEN));
+    field = aml_field(AML_GED_EVT_REG, AML_DWORD_ACC, AML_NOLOCK,
+                      AML_WRITE_AS_ZEROS);
+    aml_append(field, aml_named_field(AML_GED_EVT_SEL,
+                                      ACPI_GED_EVT_SEL_LEN * BITS_PER_BYTE));
+    aml_append(dev, field);
+
+    /*
+     * For each GED event we:
+     * - Add a conditional block for each event, inside a loop.
+     * - Call a method for each supported GED event type.
+     *
+     * The resulting ASL code looks like:
+     *
+     * Local0 = ESEL
+     * If ((Local0 & One) == One)
+     * {
+     *     MethodEvent0()
+     * }
+     *
+     * If ((Local0 & 0x2) == 0x2)
+     * {
+     *     MethodEvent1()
+     * }
+     * ...
+     */
+    evt = aml_method("_EVT", 1, AML_SERIALIZED);
+    {
+        Aml *if_ctx;
+        uint32_t i;
+        uint32_t ged_events = ctpop32(s->ged_event_bitmap);
+
+        /* Local0 = ESEL */
+        aml_append(evt, aml_store(esel, evt_sel));
+
+        for (i = 0; i < ARRAY_SIZE(ged_supported_events) && ged_events; i++) {
+            uint32_t event = s->ged_event_bitmap & ged_supported_events[i];
+
+            if (!event) {
+                continue;
+            }
+
+            if_ctx = aml_if(aml_equal(aml_and(evt_sel, aml_int(event), NULL),
+                                      aml_int(event)));
+            switch (event) {
+            case ACPI_GED_MEM_HOTPLUG_EVT:
+                aml_append(if_ctx, aml_call0(MEMORY_DEVICES_CONTAINER "."
+                                             MEMORY_SLOT_SCAN_METHOD));
+                break;
+            default:
+                /*
+                 * Please make sure all the events in ged_supported_events[]
+                 * are handled above.
+                 */
+                g_assert_not_reached();
+            }
+
+            aml_append(evt, if_ctx);
+            ged_events--;
+        }
+
+        if (ged_events) {
+            error_report("GED: Unsupported events specified");
+            exit(1);
+        }
+    }
+
+    /* Append _EVT method */
+    aml_append(dev, evt);
+
+    aml_append(table, dev);
+}
+
+/* Memory read by the GED _EVT AML dynamic method */
+static uint64_t ged_read(void *opaque, hwaddr addr, unsigned size)
+{
+    uint64_t val = 0;
+    GEDState *ged_st = opaque;
+
+    switch (addr) {
+    case ACPI_GED_EVT_SEL_OFFSET:
+        /* Read the selector value and reset it */
+        qemu_mutex_lock(&ged_st->lock);
+        val = ged_st->sel;
+        ged_st->sel = 0;
+        qemu_mutex_unlock(&ged_st->lock);
+        break;
+    default:
+        break;
+    }
+
+    return val;
+}
+
+/* Nothing is expected to be written to the GED memory region */
+static void ged_write(void *opaque, hwaddr addr, uint64_t data,
+                      unsigned int size)
+{
+}
+
+static const MemoryRegionOps ged_ops = {
+    .read = ged_read,
+    .write = ged_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
+};
+
+static void acpi_ged_event(AcpiGedState *s, uint32_t sel)
+{
+    GEDState *ged_st = &s->ged_state;
+    /*
+     * Set the GED IRQ selector to the expected device type value. This
+     * way, the ACPI method will be able to trigger the right code based
+     * on a unique IRQ.
+     */
+    qemu_mutex_lock(&ged_st->lock);
+    ged_st->sel |= sel;
+    qemu_mutex_unlock(&ged_st->lock);
+
+    /* Trigger the event by sending an interrupt to the guest. */
+    qemu_irq_pulse(s->irq);
+}
+
+static void acpi_ged_init(MemoryRegion *as, DeviceState *dev, GEDState *ged_st)
+{
+    AcpiGedState *s = ACPI_GED(dev);
+
+    assert(s->ged_base);
+
+    qemu_mutex_init(&ged_st->lock);
+    memory_region_init_io(&ged_st->io, OBJECT(dev), &ged_ops, ged_st,
+                          TYPE_ACPI_GED, ACPI_GED_REG_LEN);
+    memory_region_add_subregion(as, s->ged_base, &ged_st->io);
+    qdev_init_gpio_out_named(DEVICE(s), &s->irq, "ged-irq", 1);
+}
+
+static void acpi_ged_device_plug_cb(HotplugHandler *hotplug_dev,
+                                    DeviceState *dev, Error **errp)
+{
+    AcpiGedState *s = ACPI_GED(hotplug_dev);
+
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        if (s->memhp_state.is_enabled) {
+            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state, dev, errp);
+        } else {
+            error_setg(errp,
+                 "memory hotplug is not enabled: %s.memory-hotplug-support "
+                 "is not set", object_get_typename(OBJECT(s)));
+        }
+    } else {
+        error_setg(errp, "virt: device plug request for unsupported device"
+                   " type: %s", object_get_typename(OBJECT(dev)));
+    }
+}
+
+static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
+{
+    AcpiGedState *s = ACPI_GED(adev);
+    uint32_t sel;
+
+    if (ev & ACPI_MEMORY_HOTPLUG_STATUS) {
+        sel = ACPI_GED_MEM_HOTPLUG_EVT;
+    } else {
+        /* Unknown event. Return without generating interrupt. */
+        warn_report("GED: Unsupported event %d. No irq injected", ev);
+        return;
+    }
+
+    /*
+     * We inject the hotplug interrupt. The IRQ selector will make
+     * the difference from the ACPI table.
+     */
+    acpi_ged_event(s, sel);
+}
+
+static void acpi_ged_device_realize(DeviceState *dev, Error **errp)
+{
+    AcpiGedState *s = ACPI_GED(dev);
+
+    if (s->memhp_state.is_enabled) {
+        acpi_memory_hotplug_init(get_system_memory(), OBJECT(dev),
+                                 &s->memhp_state,
+                                 s->memhp_base);
+    }
+
+    acpi_ged_init(get_system_memory(), dev, &s->ged_state);
+}
+
+static Property acpi_ged_properties[] = {
+    /*
+     * Memory hotplug base address is a property of GED here,
+     * because GED handles memory hotplug event and acpi-mem-hotplug
+     * memory region gets initialized when GED device is realized.
+     */
+    DEFINE_PROP_UINT64("memhp-base", AcpiGedState, memhp_base, 0),
+    DEFINE_PROP_BOOL("memory-hotplug-support", AcpiGedState,
+                     memhp_state.is_enabled, true),
+    DEFINE_PROP_UINT64("ged-base", AcpiGedState, ged_base, 0),
+    DEFINE_PROP_UINT32("ged-event", AcpiGedState, ged_event_bitmap, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static bool vmstate_test_use_memhp(void *opaque)
+{
+    AcpiGedState *s = opaque;
+    return s->memhp_state.is_enabled;
+}
+
+static const VMStateDescription vmstate_memhp_state = {
+    .name = "acpi-ged/memhp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = vmstate_test_use_memhp,
+    .fields      = (VMStateField[]) {
+        VMSTATE_MEMORY_HOTPLUG(memhp_state, AcpiGedState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_ged_state = {
+    .name = "acpi-ged-state",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields      = (VMStateField[]) {
+        VMSTATE_UINT32(sel, GEDState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_acpi_ged = {
+    .name = "acpi-ged",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_STRUCT(ged_state, AcpiGedState, 1, vmstate_ged_state, GEDState),
+        VMSTATE_END_OF_LIST(),
+    },
+    .subsections = (const VMStateDescription * []) {
+        &vmstate_memhp_state,
+        NULL
+    }
+};
+
+static void acpi_ged_class_init(ObjectClass *class, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(class);
+    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(class);
+    AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_CLASS(class);
+
+    dc->desc = "ACPI Generic Event Device";
+    dc->props = acpi_ged_properties;
+    dc->realize = acpi_ged_device_realize;
+    dc->vmsd = &vmstate_acpi_ged;
+
+    hc->plug = acpi_ged_device_plug_cb;
+
+    adevc->send_event = acpi_ged_send_event;
+}
+
+static const TypeInfo acpi_ged_info = {
+    .name          = TYPE_ACPI_GED,
+    .parent        = TYPE_DEVICE,
+    .instance_size = sizeof(AcpiGedState),
+    .class_init    = acpi_ged_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_HOTPLUG_HANDLER },
+        { TYPE_ACPI_DEVICE_IF },
+        { }
+    }
+};
+
+static void acpi_ged_register_types(void)
+{
+    type_register_static(&acpi_ged_info);
+}
+
+type_init(acpi_ged_register_types)
diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
new file mode 100644
index 0000000000..f69d084c89
--- /dev/null
+++ b/include/hw/acpi/generic_event_device.h
@@ -0,0 +1,102 @@ 
+/*
+ *
+ * Copyright (c) 2018 Intel Corporation
+ * Copyright (c) 2019 Huawei Technologies R & D (UK) Ltd
+ * Written by Samuel Ortiz, Shameer Kolothum
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * The ACPI Generic Event Device (GED) is a hardware-reduced specific
+ * device[ACPI v6.1 Section 5.6.9] that handles all platform events,
+ * including the hotplug ones. Generic Event Device allows platforms
+ * to handle interrupts in ACPI ASL statements. It follows a very
+ * similar approach like the _EVT method from GPIO events. All
+ * interrupts are listed in  _CRS and the handler is written in _EVT
+ * method. Here, we use a single interrupt for the GED device, relying
+ * on IO memory region to communicate the type of device affected by
+ * the interrupt. This way, we can support up to 32 events with a
+ * unique interrupt.
+ *
+ * Here is an example.
+ *
+ * Device (\_SB.GED)
+ * {
+ *     Name (_HID, "ACPI0013")
+ *     Name (_UID, Zero)
+ *     Name (_CRS, ResourceTemplate ()
+ *     {
+ *         Interrupt (ResourceConsumer, Edge, ActiveHigh, Exclusive, ,, )
+ *         {
+ *              0x00000029,
+ *         }
+ *     })
+ *     OperationRegion (EREG, SystemMemory, 0x09080000, 0x04)
+ *     Field (EREG, DWordAcc, NoLock, WriteAsZeros)
+ *     {
+ *         ESEL,   32
+ *     }
+ *
+ *     Method (_EVT, 1, Serialized)  // _EVT: Event
+ *     {
+ *         Local0 = ESEL // ESEL = IO memory region which specifies the
+ *                       // device type.
+ *         If (((Local0 & One) == One))
+ *         {
+ *             MethodEvent1()
+ *         }
+ *         If ((Local0 & 0x2) == 0x2)
+ *         {
+ *             MethodEvent2()
+ *         }
+ *         ...
+ *     }
+ * }
+ *
+ */
+
+#ifndef HW_ACPI_GED_H
+#define HW_ACPI_GED_H
+
+#include "hw/acpi/memory_hotplug.h"
+
+#define TYPE_ACPI_GED "acpi-ged"
+#define ACPI_GED(obj) \
+    OBJECT_CHECK(AcpiGedState, (obj), TYPE_ACPI_GED)
+
+#define ACPI_GED_EVT_SEL_OFFSET    0x0
+#define ACPI_GED_EVT_SEL_LEN       0x4
+#define ACPI_GED_REG_LEN           0x4
+
+#define GED_DEVICE      "GED"
+#define AML_GED_EVT_REG "EREG"
+#define AML_GED_EVT_SEL "ESEL"
+
+/*
+ * Platforms need to specify the GED event bitmap
+ * to describe what kind of events they want to support
+ * through GED.
+ */
+#define ACPI_GED_MEM_HOTPLUG_EVT   0x1
+
+typedef struct GEDState {
+    MemoryRegion io;
+    uint32_t     sel;
+    QemuMutex    lock;
+} GEDState;
+
+typedef struct AcpiGedState {
+    DeviceClass parent_obj;
+    MemHotplugState memhp_state;
+    hwaddr memhp_base;
+    hwaddr ged_base;
+    GEDState ged_state;
+    uint32_t ged_event_bitmap;
+    qemu_irq irq;
+} AcpiGedState;
+
+void build_ged_aml(Aml *table, const char* name, HotplugHandler *hotplug_dev,
+                   uint32_t ged_irq, AmlRegionSpace rs);
+
+#endif