Hi Eric,
> -----Original Message-----
> From: Auger Eric [mailto:eric.au...@redhat.com]
> Sent: 29 March 2019 13:09
> To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com>;
> qemu-devel@nongnu.org; qemu-...@nongnu.org; imamm...@redhat.com;
> peter.mayd...@linaro.org; shannon.zha...@gmail.com;
> sa...@linux.intel.com; sebastien.bo...@intel.com
> Cc: Linuxarm <linux...@huawei.com>; xuwei (O) <xuw...@huawei.com>
> Subject: Re: [PATCH v3 09/10] hw/acpi: Add ACPI Generic Event Device Support
>
> Hi Shameer,
>
> On 3/21/19 11:47 AM, Shameer Kolothum wrote:
> > From: Samuel Ortiz <sa...@linux.intel.com>
> >
> > The ACPI Generic Event Device (GED) is a hardware-reduced specific
> > device that handles all platform events, including the hotplug ones.
> > This patch generates the AML code that defines GEDs.
> >
> > Platforms need to specify their own GedEvent array 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 is in preparation for making use of GED for ARM/virt
> > platform and for now supports only memory hotplug.
>
> Personally I would squash this with PATCH 3.
Ok.
> > Signed-off-by: Samuel Ortiz <sa...@linux.intel.com>
> > Signed-off-by: Sebastien Boeuf <sebastien.bo...@intel.com>
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
> > ---
> > hw/acpi/generic_event_device.c | 200
> +++++++++++++++++++++++++++++++++
> > include/hw/acpi/generic_event_device.h | 34 ++++++
> > 2 files changed, 234 insertions(+)
> >
> > diff --git a/hw/acpi/generic_event_device.c
> b/hw/acpi/generic_event_device.c
> > index 0b32fc9..9deaa33 100644
> > --- a/hw/acpi/generic_event_device.c
> > +++ b/hw/acpi/generic_event_device.c
> > @@ -23,6 +23,183 @@
> > #include "hw/acpi/generic_event_device.h"
> > #include "hw/mem/pc-dimm.h"
> >
> > +static hwaddr ged_io_base;
> > +static GedEvent *ged_events;
> > +static uint32_t ged_events_size;
> > +
> > +static Aml *ged_event_aml(const GedEvent *event)
> > +{
> > +
> > + if (!event) {
> > + return NULL;
> > + }
> > +
> > + switch (event->event) {
> > + case GED_MEMORY_HOTPLUG:
> > + /* We run a complete memory SCAN when getting a memory
> hotplug event */
> > + return aml_call0(MEMORY_DEVICES_CONTAINER "."
> MEMORY_SLOT_SCAN_METHOD);
> > + default:
> > + break;
> > + }
> > +
> > + return NULL;
> > +}
> > +
> > +/*
> > + * 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
> > + * GedEvent array 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.
>
> During last review I asked the question herefater. I may have missed
> your answer but just in case.
>
> 5.6.9.1 says:
> "
> The platform declare its support for the GED, and query whether an OS
> supports it, via the _OSC method
> "
> Is it something done?
Yes you did raise this earlier and I had replied as well :).
https://patchwork.kernel.org/patch/10844557/
" Right. _OSC is not defined and I don’t see Qemu ever defined platform wide
OSPM capabilities. I can see that it does that for PCI/PCIe hierarchies.
Moreover looking at the Linux code, it doesn’t seems to care about
GED definition either,
https://elixir.bootlin.com/linux/v5.0/source/include/linux/acpi.h#L490
I can try adding _OSC declaring just the GED bit for future, but not sure
It makes much difference as of now.
Please let me know if there is a strong argument for it.
"
> > + */
> > +void build_ged_aml(Aml *table, const char *name, uint32_t ged_irq,
> > + AmlRegionSpace rs)
> > +{
> > + Aml *crs = aml_resource_template();
> > + Aml *evt, *field;
> > + Aml *dev = aml_device("%s", name);
> > + Aml *irq_sel = aml_local(0);
> > + Aml *isel = aml_name(AML_GED_IRQ_SEL);
> > + uint32_t i;
> > +
> > + if (!ged_io_base || !ged_events || !ged_events_size) {
> > + return;
> > + }
> > +
> > + /* _CRS interrupt */
> > + aml_append(crs, aml_interrupt(AML_CONSUMER, AML_EDGE,
> AML_ACTIVE_HIGH,
> > + AML_EXCLUSIVE, &ged_irq, 1));
> > + /*
> > + * For each GED event we:
> > + * - Add an interrupt to the CRS section.
> > + * - Add a conditional block for each event, inside a while loop.
> > + * This is semantically equivalent to a switch/case implementation.
> > + */
> > + evt = aml_method("_EVT", 1, AML_SERIALIZED);
> > + {
> > + Aml *ged_aml;
> > + Aml *if_ctx;
> > +
> > + /* Local0 = ISEL */
> > + aml_append(evt, aml_store(isel, irq_sel));
> > +
> > + /*
> > + * Here we want to call a method for each supported GED event
> type.
> > + * The resulting ASL code looks like:
> > + *
> > + * Local0 = ISEL
> > + * If ((Local0 & irq0) == irq0)
> > + * {
> > + * MethodEvent0()
> > + * }
> > + *
> > + * If ((Local0 & irq1) == irq1)
> > + * {
> > + * MethodEvent1()
> > + * }
> I think we could have stopped here ;-) with a ../..
Ok
> > + *
> > + * If ((Local0 & irq2) == irq2)
> > + * {
> > + * MethodEvent2()
> > + * }
> > + */
> > +
> > + for (i = 0; i < ged_events_size; i++) {
> > + ged_aml = ged_event_aml(&ged_events[i]);
> > + if (!ged_aml) {
> > + continue;
> > + }
> > +
> > + /* If ((Local1 == irq))*/
> > + if_ctx = aml_if(aml_equal(aml_and(irq_sel,
> aml_int(ged_events[i].selector), NULL), aml_int(ged_events[i].selector)));
> doesn't check_patch complain here?
It did warn but thought this has better readability. I will address this.
> > + {
> > + /* AML for this specific type of event */
> > + aml_append(if_ctx, ged_aml);
> > + }
> > +
> > + /*
> > + * We append the first "if" to the "while" context.
> > + * Other "ifs" will be "elseifs".
> > + */
> > + aml_append(evt, if_ctx);
> > + }
> > + }
> > +
> > + 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_IRQ_REG, rs,
> > + aml_int(ged_io_base + ACPI_GED_IRQ_SEL_OFFSET),
> > + ACPI_GED_IRQ_SEL_LEN));
> > + field = aml_field(AML_GED_IRQ_REG, AML_DWORD_ACC,
> AML_NOLOCK,
> > + AML_WRITE_AS_ZEROS);
> > + aml_append(field, aml_named_field(AML_GED_IRQ_SEL,
> > + ACPI_GED_IRQ_SEL_LEN *
> 8));
> > + aml_append(dev, field);
> > +
> > + /* 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_IRQ_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(GEDState *ged_st, uint32_t ged_irq_sel)
> > +{
> > + /*
> > + * 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 = ged_irq_sel;
> > + qemu_mutex_unlock(&ged_st->lock);
> > +
> > + /* Trigger the event by sending an interrupt to the guest. */
> > + qemu_irq_pulse(ged_st->gsi[ged_st->irq]);
> I don't get this. The devices uses a single irq, right?
Yes it uses single irq.
> Why can't we do like other sysbus devices, sysbus_init_irq(dev, &s->irq);
> and use
> sysbus_connect_irq(SYS_BUS_DEVICE(dev), i, pic); in virt?
I have to take a look at this.
> > +}
> > +
> > static void virt_device_plug_cb(HotplugHandler *hotplug_dev,
> > DeviceState *dev, Error **errp)
> > {
> > @@ -40,6 +217,21 @@ static void virt_device_plug_cb(HotplugHandler
> *hotplug_dev,
> >
> > static void virt_send_ged(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
> > {
> > + VirtAcpiState *s = VIRT_ACPI(adev);
> > + uint32_t sel;
> > +
> > + if (ev & ACPI_MEMORY_HOTPLUG_STATUS) {
> > + sel = ACPI_GED_IRQ_SEL_MEM;
> > + } 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->ged_state, sel);
> > }
> >
> > static void virt_device_realize(DeviceState *dev, Error **errp)
> > @@ -57,6 +249,11 @@ static Property virt_acpi_properties[] = {
> > DEFINE_PROP_UINT64("memhp_base", VirtAcpiState, memhp_base,
> 0),
> > DEFINE_PROP_BOOL("memory-hotplug-support", VirtAcpiState,
> > memhp_state.is_enabled, true),
> It may be worth to explain why the GED device owns the
> MEMORY_HOTPLUG_MMIO region. This was and still is confusing me I
> acknowledge.
I will try to add the comment here saying this is the hotplug handler/
acpi interface device and needs to initialize the memory hotplug base
region.
> > + DEFINE_PROP_PTR("gsi", VirtAcpiState, gsi),
> see the comment abour irq above.
> > + DEFINE_PROP_UINT64("ged_base", VirtAcpiState, ged_base, 0),
> > + DEFINE_PROP_UINT32("ged_irq", VirtAcpiState, ged_irq, 0),
> > + DEFINE_PROP_PTR("ged_events", VirtAcpiState, ged_events),
> > + DEFINE_PROP_UINT32("ged_events_size", VirtAcpiState,
> ged_events_size, 0),
> > DEFINE_PROP_END_OF_LIST(),
> > };
> >
> > @@ -70,6 +267,9 @@ static void virt_acpi_class_init(ObjectClass *class,
> void *data)
> > dc->props = virt_acpi_properties;
> > dc->realize = virt_device_realize;
> >
> > + /* Reason: pointer properties "gsi" and "gde_events" */
> ged_events
Thanks,
Shameer
> > + dc->user_creatable = false;
> > +
> > hc->plug = virt_device_plug_cb;
> >
> > adevc->send_event = virt_send_ged;
> > diff --git a/include/hw/acpi/generic_event_device.h
> b/include/hw/acpi/generic_event_device.h
> > index 262ca7d..7f130f3 100644
> > --- a/include/hw/acpi/generic_event_device.h
> > +++ b/include/hw/acpi/generic_event_device.h
> > @@ -24,11 +24,45 @@
> > #define VIRT_ACPI(obj) \
> > OBJECT_CHECK(VirtAcpiState, (obj), TYPE_VIRT_ACPI)
> >
> > +#define ACPI_GED_IRQ_SEL_OFFSET 0x0
> > +#define ACPI_GED_IRQ_SEL_LEN 0x4
> > +#define ACPI_GED_IRQ_SEL_MEM 0x1
> > +#define ACPI_GED_REG_LEN 0x4
> > +
> > +#define GED_DEVICE "GED"
> > +#define AML_GED_IRQ_REG "IREG"
> > +#define AML_GED_IRQ_SEL "ISEL"
> > +
> > +typedef enum {
> > + GED_MEMORY_HOTPLUG = 1,
> > +} GedEventType;
> > +
> > +typedef struct GedEvent {
> > + uint32_t selector;
> > + GedEventType event;
> > +} GedEvent;
> > +
> > +typedef struct GEDState {
> > + MemoryRegion io;
> > + uint32_t sel;
> > + uint32_t irq;
> > + qemu_irq *gsi;
> > + QemuMutex lock;
> > +} GEDState;
> > +
> > typedef struct VirtAcpiState {
> > SysBusDevice parent_obj;
> > MemHotplugState memhp_state;
> > hwaddr memhp_base;
> > + void *gsi;
> > + hwaddr ged_base;
> > + GEDState ged_state;
> > + uint32_t ged_irq;
> > + void *ged_events;
> > + uint32_t ged_events_size;
> > } VirtAcpiState;
> >
> > +void build_ged_aml(Aml *table, const char* name, uint32_t ged_irq,
> > + AmlRegionSpace rs);
> >
> > #endif
> >
>
> Thanks
>
> Eric
