Re: [Qemu-devel] [PATCH for-2.1 v2 2/2] acpi: mark ACPI tables ROM blob as extend-able on migration

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 28 Jul 2014 08:03:25 +0000
Igor Mammedov <imammedo@redhat.com> wrote:

> It fixes migration failure for machine type pc-i440fx-1.7 from
> QEMU 1.7/2.0 to QEMU 2.1
> 
> Migration fails due to ACPI tables size grows across 1.7-2.1
> versions. That causes ACPI tables ROM blob to change its size
> differently for the same configurations on different QEMU versions.
> As result migration code bails out when attempting to load
> smaller ROM blob into a bigger one on a newer QEMU.
> To trigger failure it's enough to add pci-bridge device to QEMU CLI
> 
> Marking ACPI tables ROM blob as extend-able on migration allows
> QEMU to load smaller ACPI tables from QEMU 1.7/2.0, fixing
> forward migration failure introduced since 2.0 which affects
> only configurations that cause ACPI ROM blob size change.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Self-NACK

I'm sorry for mess, I've tested it on for i386 target,
but patch breaks build for other targets.
I'll resubmit v3 shortly.

> ---
>  hw/core/loader.c     | 6 +++++-
>  hw/i386/acpi-build.c | 2 +-
>  include/hw/loader.h  | 5 +++--
>  3 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/core/loader.c b/hw/core/loader.c
> index 2bf6b8f..d09b894 100644
> --- a/hw/core/loader.c
> +++ b/hw/core/loader.c
> @@ -722,7 +722,8 @@ err:
>  
>  void *rom_add_blob(const char *name, const void *blob, size_t len,
>                     hwaddr addr, const char *fw_file_name,
> -                   FWCfgReadCallback fw_callback, void *callback_opaque)
> +                   FWCfgReadCallback fw_callback, void *callback_opaque,
> +                   bool extendable)
>  {
>      Rom *rom;
>      void *data = NULL;
> @@ -742,6 +743,9 @@ void *rom_add_blob(const char *name, const void *blob, size_t len,
>  
>          if (rom_file_has_mr) {
>              data = rom_set_mr(rom, OBJECT(fw_cfg), devpath);
> +            if (extendable) {
> +                memory_region_permit_extendable_migration(rom->mr);
> +            }
>          } else {
>              data = rom->data;
>          }
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index ebc5f03..651c06b 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1558,7 +1558,7 @@ static void *acpi_add_rom_blob(AcpiBuildState *build_state, GArray *blob,
>                                 const char *name)
>  {
>      return rom_add_blob(name, blob->data, acpi_data_len(blob), -1, name,
> -                        acpi_build_update, build_state);
> +                        acpi_build_update, build_state, true);
>  }
>  
>  static const VMStateDescription vmstate_acpi_build = {
> diff --git a/include/hw/loader.h b/include/hw/loader.h
> index 796cbf9..e5a24ac 100644
> --- a/include/hw/loader.h
> +++ b/include/hw/loader.h
> @@ -57,7 +57,8 @@ int rom_add_file(const char *file, const char *fw_dir,
>                   bool option_rom);
>  void *rom_add_blob(const char *name, const void *blob, size_t len,
>                     hwaddr addr, const char *fw_file_name,
> -                   FWCfgReadCallback fw_callback, void *callback_opaque);
> +                   FWCfgReadCallback fw_callback, void *callback_opaque,
> +                   bool extendable);
>  int rom_add_elf_program(const char *name, void *data, size_t datasize,
>                          size_t romsize, hwaddr addr);
>  int rom_load_all(void);
> @@ -70,7 +71,7 @@ void do_info_roms(Monitor *mon, const QDict *qdict);
>  #define rom_add_file_fixed(_f, _a, _i)          \
>      rom_add_file(_f, NULL, _a, _i, false)
>  #define rom_add_blob_fixed(_f, _b, _l, _a)      \
> -    rom_add_blob(_f, _b, _l, _a, NULL, NULL, NULL)
> +    rom_add_blob(_f, _b, _l, _a, NULL, NULL, NULL, false)
>  
>  #define PC_ROM_MIN_VGA     0xc0000
>  #define PC_ROM_MIN_OPTION  0xc8000