Re: [Qemu-devel] [PATCH v2] pc_sysfw: Always use alias for ISA BIOS region

[Jordan Justen]

I tested that flash device still works and the alias works with the
flash device.

I *did not* test vm state save/restore/migration.

Reviewed-by: Jordan Justen <address@hidden>

On Fri, Nov 2, 2012 at 11:55 AM, Jan Kiszka <address@hidden> wrote:
> This is no technical reason (anymore) for copying the ISA BIOS from the
> original region. Instead, refactor pc_isa_bios_init to serve both pflash
> and old-style BIOS setup.
>
> Unfortunately, the previous RAM-backed version created an additional
> vmstate section, content-wise redundant to the BIOS, but we still need
> to process it when working in compat mode.
>
> Signed-off-by: Jan Kiszka <address@hidden>
> ---
>
> Changes in v2:
>  - create dummy vmstate section to enable migration from 1.1/1.2
>
>  hw/pc_piix.c  |    4 ++++
>  hw/pc_sysfw.c |   55 +++++++++++++++++++++----------------------------------
>  2 files changed, 25 insertions(+), 34 deletions(-)
>
> diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> index cfa839c..0051b2a 100644
> --- a/hw/pc_piix.c
> +++ b/hw/pc_piix.c
> @@ -386,6 +386,10 @@ static QEMUMachine pc_machine_v1_3 = {
>              .driver   = "VGA",\
>              .property = "mmio",\
>              .value    = "off",\
> +        },{\
> +            .driver   = "pc-sysfw",\
> +            .property = "compat_vmsection",\
> +            .value    = "on",\
>          }
>
>  static QEMUMachine pc_machine_v1_2 = {
> diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
> index 9d7c5f4..a60f453 100644
> --- a/hw/pc_sysfw.c
> +++ b/hw/pc_sysfw.c
> @@ -38,40 +38,36 @@
>  typedef struct PcSysFwDevice {
>      SysBusDevice busdev;
>      uint8_t rom_only;
> +    uint32_t compat_vmsection;
>  } PcSysFwDevice;
>
>  static void pc_isa_bios_init(MemoryRegion *rom_memory,
> -                             MemoryRegion *flash_mem,
> -                             int ram_size)
> +                             MemoryRegion *bios, bool compat_vmsection)
>  {
> +    uint64_t bios_size = memory_region_size(bios);
>      int isa_bios_size;
>      MemoryRegion *isa_bios;
> -    uint64_t flash_size;
> -    void *flash_ptr, *isa_bios_ptr;
> -
> -    flash_size = memory_region_size(flash_mem);
>
>      /* map the last 128KB of the BIOS in ISA space */
> -    isa_bios_size = flash_size;
> +    isa_bios_size = bios_size;
>      if (isa_bios_size > (128 * 1024)) {
>          isa_bios_size = 128 * 1024;
>      }
>      isa_bios = g_malloc(sizeof(*isa_bios));
> -    memory_region_init_ram(isa_bios, "isa-bios", isa_bios_size);
> -    vmstate_register_ram_global(isa_bios);
> +    memory_region_init_alias(isa_bios, "isa-bios", bios,
> +                             bios_size - isa_bios_size, isa_bios_size);
>      memory_region_add_subregion_overlap(rom_memory,
>                                          0x100000 - isa_bios_size,
>                                          isa_bios,
>                                          1);
> +    memory_region_set_readonly(isa_bios, true);
>
> -    /* copy ISA rom image from top of flash memory */
> -    flash_ptr = memory_region_get_ram_ptr(flash_mem);
> -    isa_bios_ptr = memory_region_get_ram_ptr(isa_bios);
> -    memcpy(isa_bios_ptr,
> -           ((uint8_t*)flash_ptr) + (flash_size - isa_bios_size),
> -           isa_bios_size);
> +    if (compat_vmsection) {
> +        MemoryRegion *dummy_region = g_new(MemoryRegion, 1);
>
> -    memory_region_set_readonly(isa_bios, true);
> +        memory_region_init_ram(dummy_region, "isa-bios", isa_bios_size);
> +        vmstate_register_ram_global(dummy_region);
> +    }
>  }
>
>  static void pc_fw_add_pflash_drv(void)
> @@ -102,7 +98,7 @@ static void pc_fw_add_pflash_drv(void)
>  }
>
>  static void pc_system_flash_init(MemoryRegion *rom_memory,
> -                                 DriveInfo *pflash_drv)
> +                                 DriveInfo *pflash_drv, bool 
> compat_vmsection)
>  {
>      BlockDriverState *bdrv;
>      int64_t size;
> @@ -129,14 +125,14 @@ static void pc_system_flash_init(MemoryRegion 
> *rom_memory,
>                                           1, 0x0000, 0x0000, 0x0000, 0x0000, 
> 0);
>      flash_mem = pflash_cfi01_get_memory(system_flash);
>
> -    pc_isa_bios_init(rom_memory, flash_mem, size);
> +    pc_isa_bios_init(rom_memory, flash_mem, compat_vmsection);
>  }
>
>  static void old_pc_system_rom_init(MemoryRegion *rom_memory)
>  {
>      char *filename;
> -    MemoryRegion *bios, *isa_bios;
> -    int bios_size, isa_bios_size;
> +    MemoryRegion *bios;
> +    int bios_size;
>      int ret;
>
>      /* BIOS load */
> @@ -167,19 +163,7 @@ static void old_pc_system_rom_init(MemoryRegion 
> *rom_memory)
>          g_free(filename);
>      }
>
> -    /* map the last 128KB of the BIOS in ISA space */
> -    isa_bios_size = bios_size;
> -    if (isa_bios_size > (128 * 1024)) {
> -        isa_bios_size = 128 * 1024;
> -    }
> -    isa_bios = g_malloc(sizeof(*isa_bios));
> -    memory_region_init_alias(isa_bios, "isa-bios", bios,
> -                             bios_size - isa_bios_size, isa_bios_size);
> -    memory_region_add_subregion_overlap(rom_memory,
> -                                        0x100000 - isa_bios_size,
> -                                        isa_bios,
> -                                        1);
> -    memory_region_set_readonly(isa_bios, true);
> +    pc_isa_bios_init(rom_memory, bios, false);
>
>      /* map all the bios at the top of memory */
>      memory_region_add_subregion(rom_memory,
> @@ -224,7 +208,8 @@ void pc_system_firmware_init(MemoryRegion *rom_memory)
>      }
>
>      if (pflash_drv != NULL) {
> -        pc_system_flash_init(rom_memory, pflash_drv);
> +        pc_system_flash_init(rom_memory, pflash_drv,
> +                             sysfw_dev->compat_vmsection);
>      } else {
>          fprintf(stderr, "qemu: PC system firmware (pflash) not available\n");
>          exit(1);
> @@ -233,6 +218,8 @@ void pc_system_firmware_init(MemoryRegion *rom_memory)
>
>  static Property pcsysfw_properties[] = {
>      DEFINE_PROP_UINT8("rom_only", PcSysFwDevice, rom_only, 0),
> +    DEFINE_PROP_BIT("compat_vmsection", PcSysFwDevice, compat_vmsection, 0,
> +                    false),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>
> --
> 1.7.3.4