Re: [PATCH 28/35] acpi: pvpanic-isa: use AcpiDevAmlIfClass:build_dev_aml to provide device's AML

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Igor Mammedov <imammedo@redhat.com>
Cc: qemu-devel@nongnu.org, ani@anisinha.ca, minyard@acm.org,
	stefanb@linux.vnet.ibm.com, marcandre.lureau@redhat.com,
	kraxel@redhat.com
Subject: Re: [PATCH 28/35] acpi: pvpanic-isa: use AcpiDevAmlIfClass:build_dev_aml to provide device's AML
Date: Mon, 16 May 2022 16:46:29 -0400	[thread overview]
Message-ID: <20220516163547-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20220516152610.1963435-29-imammedo@redhat.com>

On Mon, May 16, 2022 at 11:26:03AM -0400, Igor Mammedov wrote:
> .. and clean up not longer needed conditionals in DSTD build code
> pvpanic-isa AML will be fetched and included when ISA bridge will
> build its own AML code (including attached devices).
> 
> Expected AML change:
>    the device under separate _SB.PCI0.ISA scope is moved directly
>    under Device(ISA) node.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
>  include/hw/misc/pvpanic.h |  9 ---------
>  hw/i386/acpi-build.c      | 37 ----------------------------------
>  hw/misc/pvpanic-isa.c     | 42 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 42 insertions(+), 46 deletions(-)
> 
> diff --git a/include/hw/misc/pvpanic.h b/include/hw/misc/pvpanic.h
> index 7f16cc9b16..e520566ab0 100644
> --- a/include/hw/misc/pvpanic.h
> +++ b/include/hw/misc/pvpanic.h
> @@ -33,13 +33,4 @@ struct PVPanicState {
>  
>  void pvpanic_setup_io(PVPanicState *s, DeviceState *dev, unsigned size);
>  
> -static inline uint16_t pvpanic_port(void)
> -{
> -    Object *o = object_resolve_path_type("", TYPE_PVPANIC_ISA_DEVICE, NULL);
> -    if (!o) {
> -        return 0;
> -    }
> -    return object_property_get_uint(o, PVPANIC_IOPORT_PROP, NULL);
> -}
> -
>  #endif
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 517818cd9f..a42f41f373 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -30,7 +30,6 @@
>  #include "hw/pci/pci.h"
>  #include "hw/core/cpu.h"
>  #include "target/i386/cpu.h"
> -#include "hw/misc/pvpanic.h"
>  #include "hw/timer/hpet.h"
>  #include "hw/acpi/acpi-defs.h"
>  #include "hw/acpi/acpi.h"
> @@ -117,7 +116,6 @@ typedef struct AcpiMiscInfo {
>  #endif
>      const unsigned char *dsdt_code;
>      unsigned dsdt_size;
> -    uint16_t pvpanic_port;
>  } AcpiMiscInfo;
>  
>  typedef struct AcpiBuildPciBusHotplugState {
> @@ -302,7 +300,6 @@ static void acpi_get_misc_info(AcpiMiscInfo *info)
>  #ifdef CONFIG_TPM
>      info->tpm_version = tpm_get_version(tpm_find());
>  #endif
> -    info->pvpanic_port = pvpanic_port();
>  }
>  
>  /*
> @@ -1749,40 +1746,6 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>          aml_append(dsdt, scope);
>      }
>  
> -    if (misc->pvpanic_port) {
> -        scope = aml_scope("\\_SB.PCI0.ISA");
> -
> -        dev = aml_device("PEVT");
> -        aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0001")));
> -
> -        crs = aml_resource_template();
> -        aml_append(crs,
> -            aml_io(AML_DECODE16, misc->pvpanic_port, misc->pvpanic_port, 1, 1)
> -        );
> -        aml_append(dev, aml_name_decl("_CRS", crs));
> -
> -        aml_append(dev, aml_operation_region("PEOR", AML_SYSTEM_IO,
> -                                              aml_int(misc->pvpanic_port), 1));
> -        field = aml_field("PEOR", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
> -        aml_append(field, aml_named_field("PEPT", 8));
> -        aml_append(dev, field);
> -
> -        /* device present, functioning, decoding, shown in UI */
> -        aml_append(dev, aml_name_decl("_STA", aml_int(0xF)));
> -
> -        method = aml_method("RDPT", 0, AML_NOTSERIALIZED);
> -        aml_append(method, aml_store(aml_name("PEPT"), aml_local(0)));
> -        aml_append(method, aml_return(aml_local(0)));
> -        aml_append(dev, method);
> -
> -        method = aml_method("WRPT", 1, AML_NOTSERIALIZED);
> -        aml_append(method, aml_store(aml_arg(0), aml_name("PEPT")));
> -        aml_append(dev, method);
> -
> -        aml_append(scope, dev);
> -        aml_append(dsdt, scope);
> -    }
> -
>      sb_scope = aml_scope("\\_SB");
>      {
>          Object *pci_host;
> diff --git a/hw/misc/pvpanic-isa.c b/hw/misc/pvpanic-isa.c
> index b84d4d458d..ccec50f61b 100644
> --- a/hw/misc/pvpanic-isa.c
> +++ b/hw/misc/pvpanic-isa.c
> @@ -22,6 +22,7 @@
>  #include "qom/object.h"
>  #include "hw/isa/isa.h"
>  #include "standard-headers/linux/pvpanic.h"
> +#include "hw/acpi/acpi_aml_interface.h"
>  
>  OBJECT_DECLARE_SIMPLE_TYPE(PVPanicISAState, PVPANIC_ISA_DEVICE)
>  
> @@ -63,6 +64,41 @@ static void pvpanic_isa_realizefn(DeviceState *dev, Error **errp)
>      isa_register_ioport(d, &ps->mr, s->ioport);
>  }
>  
> +static void build_pvpanic_isa_aml(AcpiDevAmlIf *adev, Aml *scope)
> +{
> +    Aml *crs, *field, *method;
> +    PVPanicISAState *s = PVPANIC_ISA_DEVICE(adev);
> +    Aml *dev = aml_device("PEVT");
> +
> +    aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0001")));
> +
> +    crs = aml_resource_template();
> +    aml_append(crs,
> +        aml_io(AML_DECODE16, s->ioport, s->ioport, 1, 1)
> +    );
> +    aml_append(dev, aml_name_decl("_CRS", crs));
> +
> +    aml_append(dev, aml_operation_region("PEOR", AML_SYSTEM_IO,
> +                                          aml_int(s->ioport), 1));
> +    field = aml_field("PEOR", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
> +    aml_append(field, aml_named_field("PEPT", 8));
> +    aml_append(dev, field);
> +
> +    /* device present, functioning, decoding, shown in UI */
> +    aml_append(dev, aml_name_decl("_STA", aml_int(0xF)));
> +
> +    method = aml_method("RDPT", 0, AML_NOTSERIALIZED);
> +    aml_append(method, aml_store(aml_name("PEPT"), aml_local(0)));
> +    aml_append(method, aml_return(aml_local(0)));
> +    aml_append(dev, method);
> +
> +    method = aml_method("WRPT", 1, AML_NOTSERIALIZED);
> +    aml_append(method, aml_store(aml_arg(0), aml_name("PEPT")));
> +    aml_append(dev, method);
> +
> +    aml_append(scope, dev);
> +}
> +
>  static Property pvpanic_isa_properties[] = {
>      DEFINE_PROP_UINT16(PVPANIC_IOPORT_PROP, PVPanicISAState, ioport, 0x505),
>      DEFINE_PROP_UINT8("events", PVPanicISAState, pvpanic.events,
> @@ -73,10 +109,12 @@ static Property pvpanic_isa_properties[] = {
>  static void pvpanic_isa_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> +    AcpiDevAmlIfClass *adevc = ACPI_DEV_AML_IF_CLASS(klass);
>  
>      dc->realize = pvpanic_isa_realizefn;
>      device_class_set_props(dc, pvpanic_isa_properties);
>      set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    adevc->build_dev_aml = build_pvpanic_isa_aml;
>  }
>  
>  static const TypeInfo pvpanic_isa_info = {

So this really makes the device depend on ACPI.
What if the device is also built for a platform without ACPI?
Looks like it will fail to build.

E.g. mips has ISA too. What if one was to add pvpanic there?

I am not sure how important this is at the moment, but
I think the APIs should support this cleanly.

How about an inline function along the lines of:

acpi_set_build_dev_aml(DeviceClass *dc, ....)

the build function itself is static, so compiler will
remove it if unused.

> @@ -85,6 +123,10 @@ static const TypeInfo pvpanic_isa_info = {
>      .instance_size = sizeof(PVPanicISAState),
>      .instance_init = pvpanic_isa_initfn,
>      .class_init    = pvpanic_isa_class_init,
> +    .interfaces = (InterfaceInfo[]) {
> +        { TYPE_ACPI_DEV_AML_IF },
> +        { },
> +    },
>  };
>  
>  static void pvpanic_register_types(void)
> -- 
> 2.31.1