diff mbox series

[v5,3/8] hw/acpi: Add ACPI Generic Event Device Support

Message ID 20190522162252.28568-4-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 May 22, 2019, 4:22 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>
---
v4-->v5
 -Removed gsi/irq routing code.
 -Changed GED Event array to bitmap.
 -Added Migration support.

---
 hw/acpi/Kconfig                        |   4 +
 hw/acpi/Makefile.objs                  |   1 +
 hw/acpi/generic_event_device.c         | 332 +++++++++++++++++++++++++
 include/hw/acpi/generic_event_device.h | 102 ++++++++
 4 files changed, 439 insertions(+)
 create mode 100644 hw/acpi/generic_event_device.c
 create mode 100644 include/hw/acpi/generic_event_device.h

Comments

Eric Auger June 18, 2019, 12:40 p.m. UTC | #1
Hi Shameer,

On 5/22/19 6:22 PM, Shameer Kolothum 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
. This patch
> 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>
> ---
> v4-->v5
>  -Removed gsi/irq routing code.
>  -Changed GED Event array to bitmap.
>  -Added Migration support.
> 
> ---
>  hw/acpi/Kconfig                        |   4 +
>  hw/acpi/Makefile.objs                  |   1 +
>  hw/acpi/generic_event_device.c         | 332 +++++++++++++++++++++++++
>  include/hw/acpi/generic_event_device.h | 102 ++++++++
>  4 files changed, 439 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 eca3beed75..01a8b41ef5 100644
> --- a/hw/acpi/Kconfig
> +++ b/hw/acpi/Kconfig
> @@ -27,3 +27,7 @@ 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 2d46e3789a..b753232323 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..914fe64716
> --- /dev/null
> +++ b/hw/acpi/generic_event_device.c
> @@ -0,0 +1,332 @@
> +/*
> + *
> + * 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/sysbus.h"
not needed
> +#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 (s->memhp_state.is_enabled &&
> +        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> +            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state,
> +                                dev, errp);
> +    } else {
> +        error_setg(errp, "virt: device plug request for unsupported device"
> +                   " type: %s", object_get_typename(OBJECT(dev)));
This also can fail if !s->memhp_state.is_enabled. May be worth producing
2 different messages?
> +    }
> +}
> +
> +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. */
Shouldn't we produce an error message here?
> +        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 MEMORY_HOTPLUG_DEVICE
MEMORY_HOTPLUG_DEVICE? Didn't you mean acpi-mem-hotplug 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";
Choose a more explicit description?
> +    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
> 
Besides looks good to me

Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric
Shameerali Kolothum Thodi June 19, 2019, 8:14 a.m. UTC | #2
Hi Eric,

> -----Original Message-----
> From: Auger Eric [mailto:eric.auger@redhat.com]
> Sent: 18 June 2019 13:41
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>;
> qemu-devel@nongnu.org; qemu-arm@nongnu.org; imammedo@redhat.com
> Cc: peter.maydell@linaro.org; shannon.zhaosl@gmail.com;
> sameo@linux.intel.com; sebastien.boeuf@intel.com; xuwei (O)
> <xuwei5@huawei.com>; lersek@redhat.com; ard.biesheuvel@linaro.org;
> Linuxarm <linuxarm@huawei.com>
> Subject: Re: [PATCH v5 3/8] hw/acpi: Add ACPI Generic Event Device Support
> 
> Hi Shameer,
> 
> On 5/22/19 6:22 PM, Shameer Kolothum 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
> . This patch
> > 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>
> > ---
> > v4-->v5
> >  -Removed gsi/irq routing code.
> >  -Changed GED Event array to bitmap.
> >  -Added Migration support.
> >
> > ---
> >  hw/acpi/Kconfig                        |   4 +
> >  hw/acpi/Makefile.objs                  |   1 +
> >  hw/acpi/generic_event_device.c         | 332
> +++++++++++++++++++++++++
> >  include/hw/acpi/generic_event_device.h | 102 ++++++++
> >  4 files changed, 439 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
> > eca3beed75..01a8b41ef5 100644
> > --- a/hw/acpi/Kconfig
> > +++ b/hw/acpi/Kconfig
> > @@ -27,3 +27,7 @@ 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
> > 2d46e3789a..b753232323 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..914fe64716
> > --- /dev/null
> > +++ b/hw/acpi/generic_event_device.c
> > @@ -0,0 +1,332 @@
> > +/*
> > + *
> > + * 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/sysbus.h"
> not needed

True. Missed that.

> > +#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 (s->memhp_state.is_enabled &&
> > +        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> > +            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state,
> > +                                dev, errp);
> > +    } else {
> > +        error_setg(errp, "virt: device plug request for unsupported
> device"
> > +                   " type: %s", object_get_typename(OBJECT(dev)));
> This also can fail if !s->memhp_state.is_enabled. May be worth producing
> 2 different messages?

Ok. I will add the check and treat that differently.

> > +    }
> > +}
> > +
> > +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. */
> Shouldn't we produce an error message here?

Ok.

> > +        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
> > +MEMORY_HOTPLUG_DEVICE
> MEMORY_HOTPLUG_DEVICE? Didn't you mean acpi-mem-hotplug region?

Yes. It is the memory region initialization. I will change that.

> > +     * 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";
> Choose a more explicit description?

Ok.

> > +    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
> >
> Besides looks good to me
> 
> Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks,
Shameer
diff mbox series

Patch

diff --git a/hw/acpi/Kconfig b/hw/acpi/Kconfig
index eca3beed75..01a8b41ef5 100644
--- a/hw/acpi/Kconfig
+++ b/hw/acpi/Kconfig
@@ -27,3 +27,7 @@  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 2d46e3789a..b753232323 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..914fe64716
--- /dev/null
+++ b/hw/acpi/generic_event_device.c
@@ -0,0 +1,332 @@ 
+/*
+ *
+ * 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/sysbus.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 (s->memhp_state.is_enabled &&
+        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+            acpi_memory_plug_cb(hotplug_dev, &s->memhp_state,
+                                dev, errp);
+    } 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. */
+        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 MEMORY_HOTPLUG_DEVICE
+     * 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";
+    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