Re: [PATCH v5 18/23] hw/i386/pc: Remove PCMachineClass::rsdp_in_ram

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 29 May 2024 07:15:34 +0200
Philippe Mathieu-Daudé <philmd@linaro.org> wrote:

> PCMachineClass::rsdp_in_ram was only used by the
> pc-i440fx-2.2 machine, which got removed. It is
> now always true. Remove it, simplifying acpi_setup().
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  include/hw/i386/pc.h |  1 -
>  hw/i386/acpi-build.c | 35 ++++-------------------------------
>  hw/i386/pc.c         |  1 -
>  3 files changed, 4 insertions(+), 33 deletions(-)
> 
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 808de4eca7..63568eb9e9 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -100,7 +100,6 @@ struct PCMachineClass {
>  
>      /* ACPI compat: */
>      bool has_acpi_build;
> -    bool rsdp_in_ram;
>      unsigned acpi_data_size;
>      int pci_root_uid;
>  
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index ab2d4d8dcb..ed0adb0e82 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -2495,7 +2495,6 @@ static
>  void acpi_build(AcpiBuildTables *tables, MachineState *machine)
>  {
>      PCMachineState *pcms = PC_MACHINE(machine);
> -    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
>      X86MachineState *x86ms = X86_MACHINE(machine);
>      DeviceState *iommu = pcms->iommu;
>      GArray *table_offsets;
> @@ -2667,16 +2666,6 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
>              .rsdt_tbl_offset = &rsdt,
>          };
>          build_rsdp(tables->rsdp, tables->linker, &rsdp_data);
> -        if (!pcmc->rsdp_in_ram) {
> -            /* We used to allocate some extra space for RSDP revision 2 but
> -             * only used the RSDP revision 0 space. The extra bytes were
> -             * zeroed out and not used.
> -             * Here we continue wasting those extra 16 bytes to make sure we
> -             * don't break migration for machine types 2.2 and older due to
> -             * RSDP blob size mismatch.
> -             */
> -            build_append_int_noprefix(tables->rsdp, 0, 16);
> -        }
>      }
>  
>      /* We'll expose it all to Guest so we want to reduce
> @@ -2755,7 +2744,6 @@ static const VMStateDescription vmstate_acpi_build = {
>  void acpi_setup(void)
>  {
>      PCMachineState *pcms = PC_MACHINE(qdev_get_machine());
> -    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
>      X86MachineState *x86ms = X86_MACHINE(pcms);
>      AcpiBuildTables tables;
>      AcpiBuildState *build_state;
> @@ -2817,25 +2805,10 @@ void acpi_setup(void)
>                             tables.vmgenid);
>      }
>  
> -    if (!pcmc->rsdp_in_ram) {
> -        /*
> -         * Keep for compatibility with old machine types.
> -         * Though RSDP is small, its contents isn't immutable, so
> -         * we'll update it along with the rest of tables on guest access.
> -         */
> -        uint32_t rsdp_size = acpi_data_len(tables.rsdp);
> -
> -        build_state->rsdp = g_memdup(tables.rsdp->data, rsdp_size);
> -        fw_cfg_add_file_callback(x86ms->fw_cfg, ACPI_BUILD_RSDP_FILE,
> -                                 acpi_build_update, NULL, build_state,
> -                                 build_state->rsdp, rsdp_size, true);
> -        build_state->rsdp_mr = NULL;
> -    } else {
> -        build_state->rsdp = NULL;
> -        build_state->rsdp_mr = acpi_add_rom_blob(acpi_build_update,
> -                                                 build_state, tables.rsdp,
> -                                                 ACPI_BUILD_RSDP_FILE);
> -    }
> +    build_state->rsdp = NULL;
> +    build_state->rsdp_mr = acpi_add_rom_blob(acpi_build_update,
> +                                             build_state, tables.rsdp,
> +                                             ACPI_BUILD_RSDP_FILE);
>  
>      qemu_register_reset(acpi_build_reset, build_state);
>      acpi_build_reset(build_state);
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index fae21f75aa..8e51d1f1bb 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1757,7 +1757,6 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
>  
>      pcmc->pci_enabled = true;
>      pcmc->has_acpi_build = true;
> -    pcmc->rsdp_in_ram = true;
>      pcmc->smbios_defaults = true;
>      pcmc->gigabyte_align = true;
>      pcmc->has_reserved_memory = true;