Re: [Qemu-devel] [PATCH v2] pc: acpi: force FADT rev1 for 440fx based machine types

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

On Mon, Jul 24, 2017 at 03:50:20PM +0200, Igor Mammedov wrote:
> w2k used to boot on QEMU until revision of FADT has
> been bumped to rev3
> (commit 77af8a2b hw/i386: Use Rev3 FADT (ACPI 2.0) instead of Rev1 to improve guest OS support.)
> 
> Keep PC machine at rev1 to remain compatible and Q35
> at rev3 where w2k isn't supported anyway so OSX could
> run as well.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
> v2:
>    - make pc rev1 and q35 rev3.
>        "Michael S. Tsirkin" <mst@redhat.com>
> 
> PS:
> Only compile tested.
> 
> 
> CC: Programmingkid <programmingkidx@gmail.com>
> CC: Phil Dennis-Jordan <lists@philjordan.eu>
> CC: "Michael S. Tsirkin" <mst@redhat.com>
> 
> ---
>  hw/i386/acpi-build.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 6b7bade..b9c245c 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -90,6 +90,7 @@ typedef struct AcpiMcfgInfo {
>  } AcpiMcfgInfo;
>  
>  typedef struct AcpiPmInfo {
> +    bool force_rev1_fadt;
>      bool s3_disabled;
>      bool s4_disabled;
>      bool pcihp_bridge_en;
> @@ -129,10 +130,13 @@ static void acpi_get_pm_info(AcpiPmInfo *pm)
>      Object *obj = NULL;
>      QObject *o;
>  
> +    pm->force_rev1_fadt = false;
>      pm->cpu_hp_io_base = 0;
>      pm->pcihp_io_base = 0;
>      pm->pcihp_io_len = 0;
>      if (piix) {
> +        /* w2k requires FADT(rev1) or it won't boot, keep PC compatible */
> +        pm->force_rev1_fadt = true;
>          obj = piix;
>          pm->cpu_hp_io_base = PIIX4_CPU_HOTPLUG_IO_BASE;
>          pm->pcihp_io_base =
> @@ -304,6 +308,9 @@ static void fadt_setup(AcpiFadtDescriptorRev3 *fadt, AcpiPmInfo *pm)
>          fadt->flags |= cpu_to_le32(1 << ACPI_FADT_F_FORCE_APIC_CLUSTER_MODEL);
>      }
>      fadt->century = RTC_CENTURY;
> +    if (pm->force_rev1_fadt) {
> +        return;
> +    }
>  
>      fadt->flags |= cpu_to_le32(1 << ACPI_FADT_F_RESET_REG_SUP);
>      fadt->reset_value = 0xf;
> @@ -342,6 +349,8 @@ build_fadt(GArray *table_data, BIOSLinker *linker, AcpiPmInfo *pm,
>      unsigned fw_ctrl_offset = (char *)&fadt->firmware_ctrl - table_data->data;
>      unsigned dsdt_entry_offset = (char *)&fadt->dsdt - table_data->data;
>      unsigned xdsdt_entry_offset = (char *)&fadt->x_dsdt - table_data->data;
> +    int fadt_size = sizeof(*fadt);
> +    int rev = 3;
>  
>      /* FACS address to be filled by Guest linker */
>      bios_linker_loader_add_pointer(linker,
> @@ -353,12 +362,17 @@ build_fadt(GArray *table_data, BIOSLinker *linker, AcpiPmInfo *pm,
>      bios_linker_loader_add_pointer(linker,
>          ACPI_BUILD_TABLE_FILE, dsdt_entry_offset, sizeof(fadt->dsdt),
>          ACPI_BUILD_TABLE_FILE, dsdt_tbl_offset);
> -    bios_linker_loader_add_pointer(linker,
> -        ACPI_BUILD_TABLE_FILE, xdsdt_entry_offset, sizeof(fadt->x_dsdt),
> -        ACPI_BUILD_TABLE_FILE, dsdt_tbl_offset);
> +    if (pm->force_rev1_fadt) {
> +        rev = 1;
> +        fadt_size = offsetof(typeof(*fadt), reset_register);

I don't really like it that we are using structs to format fields - I
would prefer build_append_int_noprefix based APIs - but since we do,
let's add a proper structure for FADT rev 1 instead of this hack.

While we are at it, maybe we should replace macro hacks like
ACPI_FADT_COMMON_DEF with simple sub-structures (unless you see a reason
not to).


> +    } else {
> +        bios_linker_loader_add_pointer(linker,
> +            ACPI_BUILD_TABLE_FILE, xdsdt_entry_offset, sizeof(fadt->x_dsdt),
> +            ACPI_BUILD_TABLE_FILE, dsdt_tbl_offset);
> +    }
>  
>      build_header(linker, table_data,
> -                 (void *)fadt, "FACP", sizeof(*fadt), 3, oem_id, oem_table_id);
> +                 (void *)fadt, "FACP", fadt_size, rev, oem_id, oem_table_id);
>  }
>  
>  void pc_madt_cpu_entry(AcpiDeviceIf *adev, int uid,
> -- 
> 2.7.4