Re: [Qemu-devel] [PATCH] pc: acpi-build: make linker & RSDP tables dynamic

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

On Tue, Jun 17, 2014 at 10:14:01PM +0200, Igor Mammedov wrote:
> linker and RSDP tables are build only once, so if later
> during rebuild sizes of ACPI tables change pointers will
> be patched incorrectly due to wrong offsets.
> 
> To fix it rebuild linker and RSDP tables along with
> the rest of ACPI tables so that they would have correct
> offsets.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>

If you are adding a new blob you are breaking cross-version migration.
Need to handle that depending on pc version as appropriate.

> ---
>  hw/i386/acpi-build.c | 21 ++++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index fab25ad..8301bb4 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1862,6 +1862,10 @@ struct AcpiBuildState {
>      /* Copy of table in RAM (for patching). */
>      uint8_t *table_ram;
>      uint32_t table_size;
> +    uint8_t *linker_ram;
> +    uint32_t linker_size;
> +    uint8_t *rsdp_ram;
> +    uint32_t rsdp_size;
>      /* Is table patched? */
>      uint8_t patched;
>      PcGuestInfo *guest_info;
> @@ -1998,6 +2002,10 @@ static void acpi_build_update(void *build_opaque, uint32_t offset)
>      assert(acpi_data_len(tables.table_data) == build_state->table_size);
>      memcpy(build_state->table_ram, tables.table_data->data,
>             build_state->table_size);
> +    memcpy(build_state->linker_ram, tables.linker->data,
> +           build_state->linker_size);
> +    memcpy(build_state->rsdp_ram, tables.rsdp->data,
> +           build_state->rsdp_size);
>  
>      acpi_build_tables_cleanup(&tables, true);
>  }
> @@ -2060,14 +2068,13 @@ void acpi_setup(PcGuestInfo *guest_info)
>                                                 ACPI_BUILD_TABLE_FILE);
>      build_state->table_size = acpi_data_len(tables.table_data);
>  
> -    acpi_add_rom_blob(NULL, tables.linker, "etc/table-loader");
> +    build_state->linker_ram = acpi_add_rom_blob(build_state, tables.linker,
> +                                                "etc/table-loader");
> +    build_state->linker_size = acpi_data_len(tables.linker);
>  
> -    /*
> -     * RSDP is small so it's easy to keep it immutable, no need to
> -     * bother with ROM blobs.
> -     */
> -    fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_RSDP_FILE,
> -                    tables.rsdp->data, acpi_data_len(tables.rsdp));
> +    build_state->rsdp_ram = acpi_add_rom_blob(build_state, tables.rsdp,
> +                                              ACPI_BUILD_RSDP_FILE);
> +    build_state->rsdp_size = acpi_data_len(tables.rsdp);
>  
>      qemu_register_reset(acpi_build_reset, build_state);
>      acpi_build_reset(build_state);
> -- 
> 1.9.3