Re: [Qemu-devel] [PATCH 3/6] fw_cfg: move setting of FW_CFG_ID into fw_cfg_init1()

[Igor Mammedov <imammedo@redhat.com>]

On Sat, 10 Jun 2017 13:30:18 +0100
Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> wrote:

> The dma_enabled property enables us to set the FW_CFG_ID version
> accordingly.
it might be not safe as patch reorders FW_CFG_ID entry.

(I recall there were patches that sorted fwcfg entries,
but it's worth checking that it won't break migration)

CCing Gerd, maybe he would recall how it works.

> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>  hw/nvram/fw_cfg.c |   16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
> index 1313bfd..f7b78a9 100644
> --- a/hw/nvram/fw_cfg.c
> +++ b/hw/nvram/fw_cfg.c
> @@ -914,12 +914,19 @@ static void fw_cfg_init1(DeviceState *dev)
>  {
>      FWCfgState *s = FW_CFG(dev);
>      MachineState *machine = MACHINE(qdev_get_machine());
> +    uint32_t version = FW_CFG_VERSION;
>  
>      assert(!object_resolve_path(FW_CFG_PATH, NULL));
>  
>      object_property_add_child(OBJECT(machine), FW_CFG_NAME, OBJECT(s), NULL);
>  
>      fw_cfg_add_bytes(s, FW_CFG_SIGNATURE, (char *)"QEMU", 4);
> +
> +    if (s->dma_enabled) {
> +        version |= FW_CFG_VERSION_DMA;
> +    }
> +
> +    fw_cfg_add_i32(s, FW_CFG_ID, version);
>      fw_cfg_add_bytes(s, FW_CFG_UUID, &qemu_uuid, 16);
>      fw_cfg_add_i16(s, FW_CFG_NOGRAPHIC, (uint16_t)!machine->enable_graphics);
>      fw_cfg_add_i16(s, FW_CFG_BOOT_MENU, (uint16_t)boot_menu);
> @@ -935,7 +942,6 @@ FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t dma_iobase,
>  {
>      DeviceState *dev;
>      FWCfgState *s;
> -    uint32_t version = FW_CFG_VERSION;
>      bool dma_requested = dma_iobase && dma_as;
>  
>      dev = qdev_create(NULL, TYPE_FW_CFG_IO);
> @@ -954,12 +960,8 @@ FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t dma_iobase,
>          /* 64 bits for the address field */
>          s->dma_as = dma_as;
>          s->dma_addr = 0;
> -
> -        version |= FW_CFG_VERSION_DMA;
>      }
>  
> -    fw_cfg_add_i32(s, FW_CFG_ID, version);
> -
>      return s;
>  }
>  
> @@ -975,7 +977,6 @@ FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
>      DeviceState *dev;
>      SysBusDevice *sbd;
>      FWCfgState *s;
> -    uint32_t version = FW_CFG_VERSION;
>      bool dma_requested = dma_addr && dma_as;
>  
>      dev = qdev_create(NULL, TYPE_FW_CFG_MEM);
> @@ -997,11 +998,8 @@ FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
>          s->dma_as = dma_as;
>          s->dma_addr = 0;
>          sysbus_mmio_map(sbd, 2, dma_addr);
> -        version |= FW_CFG_VERSION_DMA;
>      }
>  
> -    fw_cfg_add_i32(s, FW_CFG_ID, version);
> -
>      return s;
>  }
>