Re: [Qemu-devel] [PATCH v2] isapc: Fix non-KVM qemu boot (read/write memory for isapc BIOS)

[Anthony Liguori <anthony@codemonkey.ws>]

Jordan Justen <jordan.l.justen@intel.com> writes:

> The isapc machine with seabios currently requires the BIOS region
> to be read/write memory rather than read-only memory.
>
> KVM currently cannot support the BIOS as a ROM region, but qemu
> in non-KVM mode can. Based on this, isapc machine currently only
> works with KVM.
>
> To work-around this isapc issue, this change avoids marking the
> BIOS as readonly for isapc.
>
> This change also will allow KVM to start supporting ROM mode
> via KVM_CAP_READONLY_MEM.
>
> Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> v2:
>  * Fix build issue with this patch. Apologies for not testing
>    this patch outside of my kvm-flash series.

This needs to be rebased post-Paolo's revert.

Make sure you've got at least:

commit 9e1c2ec8fd8d9a9ee299ea86c5f6c986fe25e838
Author: Paolo Bonzini <pbonzini@redhat.com>
Date:   Fri May 10 14:38:03 2013 +0200

    Revert "pc: Kill the "use flash device for BIOS unless KVM" misfeature"
 
Regards,

Anthony Liguori

>
>  hw/block/pc_sysfw.c |   16 +++++++++++-----
>  hw/i386/pc_piix.c   |    5 +++++
>  2 files changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/hw/block/pc_sysfw.c b/hw/block/pc_sysfw.c
> index aad8614..a02f320 100644
> --- a/hw/block/pc_sysfw.c
> +++ b/hw/block/pc_sysfw.c
> @@ -39,6 +39,7 @@
>  typedef struct PcSysFwDevice {
>      SysBusDevice busdev;
>      uint8_t rom_only;
> +    uint8_t isapc_ram_fw;
>  } PcSysFwDevice;
>  
>  static void pc_isa_bios_init(MemoryRegion *rom_memory,
> @@ -139,7 +140,7 @@ static void pc_system_flash_init(MemoryRegion *rom_memory,
>      pc_isa_bios_init(rom_memory, flash_mem, size);
>  }
>  
> -static void old_pc_system_rom_init(MemoryRegion *rom_memory)
> +static void old_pc_system_rom_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
>  {
>      char *filename;
>      MemoryRegion *bios, *isa_bios;
> @@ -163,7 +164,9 @@ static void old_pc_system_rom_init(MemoryRegion *rom_memory)
>      bios = g_malloc(sizeof(*bios));
>      memory_region_init_ram(bios, "pc.bios", bios_size);
>      vmstate_register_ram_global(bios);
> -    memory_region_set_readonly(bios, true);
> +    if (!isapc_ram_fw) {
> +        memory_region_set_readonly(bios, true);
> +    }
>      ret = rom_add_file_fixed(bios_name, (uint32_t)(-bios_size), -1);
>      if (ret != 0) {
>      bios_error:
> @@ -186,7 +189,9 @@ static void old_pc_system_rom_init(MemoryRegion *rom_memory)
>                                          0x100000 - isa_bios_size,
>                                          isa_bios,
>                                          1);
> -    memory_region_set_readonly(isa_bios, true);
> +    if (!isapc_ram_fw) {
> +        memory_region_set_readonly(isa_bios, true);
> +    }
>  
>      /* map all the bios at the top of memory */
>      memory_region_add_subregion(rom_memory,
> @@ -216,7 +221,7 @@ void pc_system_firmware_init(MemoryRegion *rom_memory)
>      qdev_init_nofail(DEVICE(sysfw_dev));
>  
>      if (sysfw_dev->rom_only) {
> -        old_pc_system_rom_init(rom_memory);
> +        old_pc_system_rom_init(rom_memory, sysfw_dev->isapc_ram_fw);
>          return;
>      }
>  
> @@ -234,7 +239,7 @@ void pc_system_firmware_init(MemoryRegion *rom_memory)
>              exit(1);
>          } else {
>              sysfw_dev->rom_only = 1;
> -            old_pc_system_rom_init(rom_memory);
> +            old_pc_system_rom_init(rom_memory, sysfw_dev->isapc_ram_fw);
>              return;
>          }
>      }
> @@ -255,6 +260,7 @@ void pc_system_firmware_init(MemoryRegion *rom_memory)
>  }
>  
>  static Property pcsysfw_properties[] = {
> +    DEFINE_PROP_UINT8("isapc_ram_fw", PcSysFwDevice, isapc_ram_fw, 0),
>      DEFINE_PROP_UINT8("rom_only", PcSysFwDevice, rom_only, 1),
>      DEFINE_PROP_END_OF_LIST(),
>  };
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index f7c80ad..c1a49ec 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -716,6 +716,11 @@ static QEMUMachine isapc_machine = {
>              .property = "rom_only",
>              .value    = stringify(1),
>          },
> +        {
> +            .driver   = "pc-sysfw",
> +            .property = "isapc_ram_fw",
> +            .value    = stringify(1),
> +        },
>          { /* end of list */ }
>      },
>      DEFAULT_MACHINE_OPTIONS,
> -- 
> 1.7.10.4