Re: [PATCH 1/3] acpi/ged: Implement S3 and S4 sleep

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jul 25, 2024 at 10:22:15AM +0200, Igor Mammedov wrote:
> On Thu, 13 Jun 2024 18:30:15 +0100
> Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
> 
> > Implement S3 and S4 sleep with ACPI_GED_REG_SLEEP_CTL.SLP_TYP
> > writes.
> > 
> > Implement wakeup callback and WAK_STS register to inform guest
> > about current states.
> > 
> > All new functions are gated by "slp-typs" property, it is defaulted
> > to S5 only and machines can opt-in for S3 and S4.
> 
> subject says S3 + S4 and don't mention S5
> the same happens throughout the series, please fix it up
> 
> PS:
> please reference relevant ACPI portions in the patch below,
> so reader could easily find and understand what code does.
> 
> > 
> > Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> > ---
> >  hw/acpi/generic_event_device.c         | 70 ++++++++++++++++++++++++++++++----
> >  include/hw/acpi/generic_event_device.h | 12 +++++-
> >  2 files changed, 73 insertions(+), 9 deletions(-)
> > 
> > diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
> > index 2d6e91b124e5..f1fc99c04011 100644
> > --- a/hw/acpi/generic_event_device.c
> > +++ b/hw/acpi/generic_event_device.c
> > @@ -11,6 +11,7 @@
> >  
> >  #include "qemu/osdep.h"
> >  #include "qapi/error.h"
> > +#include "qapi/qapi-events-run-state.h"
> >  #include "hw/acpi/acpi.h"
> >  #include "hw/acpi/generic_event_device.h"
> >  #include "hw/irq.h"
> > @@ -186,24 +187,53 @@ static const MemoryRegionOps ged_evt_ops = {
> >  
> >  static uint64_t ged_regs_read(void *opaque, hwaddr addr, unsigned size)
> >  {
> > +    GEDState *ged_st = opaque;
> > +
> > +    switch (addr) {
> > +    case ACPI_GED_REG_SLEEP_STS:
> > +        return ged_st->sleep_sts;
> > +    default:
> > +        break;
> > +    }
> > +
> >      return 0;
> >  }
> >  
> >  static void ged_regs_write(void *opaque, hwaddr addr, uint64_t data,
> >                             unsigned int size)
> >  {
> > -    bool slp_en;
> > -    int slp_typ;
> > +    GEDState *ged_st = opaque;
> > +    AcpiGedState *s = container_of(ged_st, AcpiGedState, ged_state);
> >  
> >      switch (addr) {
> >      case ACPI_GED_REG_SLEEP_CTL:
> > -        slp_typ = (data >> 2) & 0x07;
> > -        slp_en  = (data >> 5) & 0x01;
> maybe use defines instead of magic numbers, it's also good to add
> coments here referring to concrete chapter in APCI spec that describe
> what these numbers are.

In fact if you add comments you do not need defines.
One time use defines are a waste of time and hard to parse.

 slp_typ = (data >> 2 /* x Yz */ ) & 0x07 /* bits 0 to 3 */;

is clearer than

#define ACPI_S3_X_YZ 2
#define ACPI_S3_MASK 7

because that "x Yz" can match spec text *exactly*, you do
text search and you find where it is. With macros
you have to guess.

build_amd_iommu is a nice example I think.

> 
> > -        if (slp_en && slp_typ == 5) {
>                                     ^^^
> ditto

this is deleted code, isn't it?

> > -            qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
> > +        if (data & ACPI_GED_SLP_EN) {
> > +            switch (extract8(data, 2, 3)) {
> > +            case ACPI_GED_SLP_TYP_S3:
> > +                if (s->slp_typs_bitmap & (1 << ACPI_GED_SLP_TYP_S3)) {
> 
> why not use existing helpers like test_bit()
> the same applies to following bit checks
> 
> > +                    qemu_system_suspend_request();
> > +                }
> > +                break;
> > +            case ACPI_GED_SLP_TYP_S4:
> > +                if (s->slp_typs_bitmap & (1 << ACPI_GED_SLP_TYP_S4)) {
> > +                    qapi_event_send_suspend_disk();
> > +                    qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
> > +                }
> > +                break;
> > +            case ACPI_GED_SLP_TYP_S5:
> > +                if (s->slp_typs_bitmap & (1 << ACPI_GED_SLP_TYP_S5)) {
> > +                    qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
> > +                }
> > +                break;
> > +            default:
> > +                break;
> > +            }
> >          }
> >          return;
> >      case ACPI_GED_REG_SLEEP_STS:
> > +        if (data & ACPI_GED_WAK_STS) {
> > +            ged_st->sleep_sts &= ~ACPI_GED_WAK_STS;
> > +        }
> >          return;
> >      case ACPI_GED_REG_RESET:
> >          if (data == ACPI_GED_RESET_VALUE) {
> > @@ -223,6 +253,14 @@ static const MemoryRegionOps ged_regs_ops = {
> >      },
> >  };
> >  
> > +static void acpi_ged_notify_wakeup(Notifier *notifier, void *data)
> > +{
> > +    GEDState *ged_st = container_of(notifier, GEDState, wakeup);
> > +
> > +    ged_st->sleep_sts |= ACPI_GED_WAK_STS;
> 
> describe somewhere workflow how it is supposed to work 
> (commit message or add ged specific doc in docs/specs/
> as the 1st patch)
> 
> > +}
> > +
> > +
> >  static void acpi_ged_device_plug_cb(HotplugHandler *hotplug_dev,
> >                                      DeviceState *dev, Error **errp)
> >  {
> > @@ -305,6 +343,8 @@ static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev)
> >  
> >  static Property acpi_ged_properties[] = {
> >      DEFINE_PROP_UINT32("ged-event", AcpiGedState, ged_event_bitmap, 0),
> > +    DEFINE_PROP_UINT32("slp-typs", AcpiGedState, slp_typs_bitmap,
> > +                        (1 << ACPI_GED_SLP_TYP_S5)),
> 
> I'd default to everything enabled, and use compat mechanism
> to disable it on older machine types.
> 
> You have to do this as ged is also used by versioned arm/virt machine
> 
> >      DEFINE_PROP_END_OF_LIST(),
> >  };
> >  
> > @@ -320,10 +360,11 @@ static const VMStateDescription vmstate_memhp_state = {
> >  
> >  static const VMStateDescription vmstate_ged_state = {
> >      .name = "acpi-ged-state",
> > -    .version_id = 1,
> > -    .minimum_version_id = 1,
> > +    .version_id = 2,
> > +    .minimum_version_id = 2,
> >      .fields = (const VMStateField[]) {
> >          VMSTATE_UINT32(sel, GEDState),
> > +        VMSTATE_UINT8(sleep_sts, GEDState),
> >          VMSTATE_END_OF_LIST()
> >      }
> >  };
> 
> see for example
> commit 829600a519386c7b188d5d813e78ba69bf0bd323
>     hpet: recover timer offset correctly
> 
> 
> 
> > @@ -371,6 +412,18 @@ static const VMStateDescription vmstate_acpi_ged = {
> >      }
> >  };
> >  
> > +static void acpi_ged_realize(DeviceState *dev, Error **errp)
> > +{
> > +    AcpiGedState *s = ACPI_GED(dev);
> > +    GEDState *ged_st = &s->ged_state;
> > +
> > +    if (s->slp_typs_bitmap & (1 << ACPI_GED_SLP_TYP_S3)) {
> > +        ged_st->wakeup.notify = acpi_ged_notify_wakeup;
> > +        qemu_register_wakeup_notifier(&ged_st->wakeup);
> > +        qemu_register_wakeup_support();
> > +    }
> > +}
> > +
> >  static void acpi_ged_initfn(Object *obj)
> >  {
> >      DeviceState *dev = DEVICE(obj);
> > @@ -409,6 +462,7 @@ static void acpi_ged_class_init(ObjectClass *class, void *data)
> >      AcpiDeviceIfClass *adevc = ACPI_DEVICE_IF_CLASS(class);
> >  
> >      dc->desc = "ACPI Generic Event Device";
> > +    dc->realize = acpi_ged_realize;
> 
> realize was added recently (currently in master),
> please rebase on top of current master tree
> 
> >      device_class_set_props(dc, acpi_ged_properties);
> >      dc->vmsd = &vmstate_acpi_ged;
> >  
> > diff --git a/include/hw/acpi/generic_event_device.h b/include/hw/acpi/generic_event_device.h
> > index ba84ce021477..1ea3cb848679 100644
> > --- a/include/hw/acpi/generic_event_device.h
> > +++ b/include/hw/acpi/generic_event_device.h
> > @@ -80,9 +80,16 @@ OBJECT_DECLARE_SIMPLE_TYPE(AcpiGedState, ACPI_GED)
> >  /* ACPI_GED_REG_RESET value for reset*/
> >  #define ACPI_GED_RESET_VALUE       0x42
> >  
> > -/* ACPI_GED_REG_SLEEP_CTL.SLP_TYP value for S5 (aka poweroff) */
> > +/* ACPI_GED_REG_SLEEP_CTL.SLP_EN bit */
> > +#define ACPI_GED_SLP_EN            (1 << 5)
> > +
> > +/* ACPI_GED_REG_SLEEP_CTL.SLP_TYP values */
> > +#define ACPI_GED_SLP_TYP_S3        0x03
> > +#define ACPI_GED_SLP_TYP_S4        0x04
> >  #define ACPI_GED_SLP_TYP_S5        0x05
> >  
> > +#define ACPI_GED_WAK_STS           (1 << 7)
> > +
> >  #define GED_DEVICE      "GED"
> >  #define AML_GED_EVT_REG "EREG"
> >  #define AML_GED_EVT_SEL "ESEL"
> > @@ -99,7 +106,9 @@ OBJECT_DECLARE_SIMPLE_TYPE(AcpiGedState, ACPI_GED)
> >  typedef struct GEDState {
> >      MemoryRegion evt;
> >      MemoryRegion regs;
> > +    Notifier     wakeup;
> >      uint32_t     sel;
> > +    uint8_t      sleep_sts;
> >  } GEDState;
> >  
> >  struct AcpiGedState {
> > @@ -108,6 +117,7 @@ struct AcpiGedState {
> >      MemoryRegion container_memhp;
> >      GEDState ged_state;
> >      uint32_t ged_event_bitmap;
> > +    uint32_t slp_typs_bitmap;
> >      qemu_irq irq;
> >      AcpiGhesState ghes_state;
> >  };
> >