Re: [Qemu-devel] [PATCH v4 3/5] acpi: pc: add fw_cfg device node to ssdt

[Laszlo Ersek <lersek@redhat.com>]

On 09/27/15 23:29, Gabriel L. Somlo wrote:
> Add a fw_cfg device node to the ACPI SSDT, on machine types
> pc-*-2.5 and up. While the guest-side BIOS can't utilize
> this information (since it has to access the hard-coded
> fw_cfg device to extract ACPI tables to begin with), having
> fw_cfg listed in ACPI will help the guest kernel keep a more
> accurate inventory of in-use IO port regions.
> 
> Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
> ---
>  hw/i386/acpi-build.c | 23 +++++++++++++++++++++++
>  hw/i386/pc_piix.c    |  1 +
>  hw/i386/pc_q35.c     |  1 +
>  include/hw/i386/pc.h |  1 +
>  4 files changed, 26 insertions(+)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 95e0c65..ece2710 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -906,6 +906,7 @@ build_ssdt(GArray *table_data, GArray *linker,
>             PcPciInfo *pci, PcGuestInfo *guest_info)
>  {
>      MachineState *machine = MACHINE(qdev_get_machine());
> +    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(machine);
>      uint32_t nr_mem = machine->ram_slots;
>      unsigned acpi_cpus = guest_info->apic_id_limit;
>      Aml *ssdt, *sb_scope, *scope, *pkg, *dev, *method, *crs, *field, *ifctx;
> @@ -1071,6 +1072,28 @@ build_ssdt(GArray *table_data, GArray *linker,
>      aml_append(scope, aml_name_decl("_S5", pkg));
>      aml_append(ssdt, scope);
>  
> +    if (!pcmc->acpi_no_fw_cfg_node) {
> +        scope = aml_scope("\\_SB");
> +        dev = aml_device("FWCF");
> +
> +        aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0002")));
> +        /* device present, functioning, decoding, not shown in UI */
> +        aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
> +
> +        crs = aml_resource_template();
> +        /* when using port i/o, the 8-bit data register *always* overlaps
> +         * with half of the 16-bit control register. Hence, the total size
> +         * of the i/o region used is FW_CFG_CTL_SIZE */
> +        aml_append(crs,
> +            aml_io(AML_DECODE16, FW_CFG_IO_BASE, FW_CFG_IO_BASE,
> +                   0x01, FW_CFG_CTL_SIZE)
> +        );

I think "aml_io" should be indented so that it lines up with "crs" above it.

Other than that:

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

What Windows guests did you test this with? ("Testing" meant as "looked
at Device Manager".) I can help with Windows 7, 8, and 10, if you'd like
that.

Thanks
Laszlo

> +        aml_append(dev, aml_name_decl("_CRS", crs));
> +
> +        aml_append(scope, dev);
> +        aml_append(ssdt, scope);
> +    }
> +
>      if (misc->applesmc_io_base) {
>          scope = aml_scope("\\_SB.PCI0.ISA");
>          dev = aml_device("SMC");
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 3ffb05f..7f5e5d9 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -482,6 +482,7 @@ static void pc_i440fx_2_4_machine_options(MachineClass *m)
>      m->alias = NULL;
>      m->is_default = 0;
>      pcmc->broken_reserved_end = true;
> +    pcmc->acpi_no_fw_cfg_node = true;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_4);
>  }
>  
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 1b7d3b6..7180ca3 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -385,6 +385,7 @@ static void pc_q35_2_4_machine_options(MachineClass *m)
>      pc_q35_2_5_machine_options(m);
>      m->alias = NULL;
>      pcmc->broken_reserved_end = true;
> +    pcmc->acpi_no_fw_cfg_node = true;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_4);
>  }
>  
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 86007e3..6d0f1bd 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -62,6 +62,7 @@ struct PCMachineClass {
>      bool broken_reserved_end;
>      HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
>                                             DeviceState *dev);
> +    bool acpi_no_fw_cfg_node;
>  };
>  
>  #define TYPE_PC_MACHINE "generic-pc-machine"
>