Re: [Qemu-devel] [PATCH v4 2/3] pc: acpi-build: update linker on guest access

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

On Mon, Feb 09, 2015 at 01:59:54PM +0000, Igor Mammedov wrote:
> Linker table is build only once, so if later during
> tables rebuild sizes of other ACPI tables change
> pointers will be patched incorrectly due to wrong
> offsets in linker. Resulting in guest not being able
> to find ACPI tables.
> Fix it by updating 'linker' table with the rest of
> tables when firmware reads it.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
>  hw/i386/acpi-build.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 5b2b017..21ea3db 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1527,6 +1527,8 @@ struct AcpiBuildState {
>      uint8_t patched;
>      PcGuestInfo *guest_info;
>      void *rsdp;
> +    ram_addr_t linker_ram;
> +    uint32_t linker_size;
>  } AcpiBuildState;
>  
>  static bool acpi_get_mcfg(AcpiMcfgInfo *mcfg)
> @@ -1733,6 +1735,8 @@ static void acpi_build_update(void *build_opaque, uint32_t offset)
>      memcpy(qemu_get_ram_ptr(build_state->table_ram), tables.table_data->data,
>             build_state->table_size);
>      memcpy(build_state->rsdp, tables.rsdp->data, acpi_data_len(tables.rsdp));
> +    memcpy(qemu_get_ram_ptr(build_state->linker_ram), tables.linker->data,
> +           build_state->linker_size);
>  
>      cpu_physical_memory_set_dirty_range_nocode(build_state->table_ram,
>                                                 build_state->table_size);

OK, but it looks like linker data needs to be marked dirty
as well. I'll send a patch to do this.

> @@ -1799,7 +1803,9 @@ void acpi_setup(PcGuestInfo *guest_info)
>      assert(build_state->table_ram != RAM_ADDR_MAX);
>      build_state->table_size = acpi_data_len(tables.table_data);
>  
> -    acpi_add_rom_blob(NULL, tables.linker, "etc/table-loader", 0);
> +    build_state->linker_ram =
> +        acpi_add_rom_blob(build_state, tables.linker, "etc/table-loader", 0);
> +    build_state->linker_size = acpi_data_len(tables.linker);
>  
>      fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_TPMLOG_FILE,
>                      tables.tcpalog->data, acpi_data_len(tables.tcpalog));
> -- 
> 1.8.3.1