Re: [Qemu-devel] [PATCHv7 5/6] fw_cfg: move qdev_init_nofail() from fw_cfg_init1() to callers

[Igor Mammedov]

On Thu, 29 Jun 2017 15:07:19 +0100
Mark Cave-Ayland <address@hidden> wrote:

> When looking to instantiate a TYPE_FW_CFG_MEM or TYPE_FW_CFG_IO device to be
> able to wire it up differently, it is much more convenient for the caller to
> instantiate the device and have the fw_cfg default files already preloaded
> during realize.
> 
> Move fw_cfg_init1() to the end of both the fw_cfg_mem_realize() and
> fw_cfg_io_realize() functions so it no longer needs to be called manually
> when instantiating the device, and also rename it to fw_cfg_common_realize()
> which better describes its new purpose.
> 
> Since it is now the responsibility of the machine to wire up the fw_cfg device
> it is necessary to introduce a object_property_add_child() call into
> fw_cfg_init_io() and fw_cfg_init_mem() to link the fw_cfg device to the root
> machine object as before.
> 
> Finally we can now convert the asserts() preventing multiple fw_cfg devices
> and unparented fw_cfg devices being instantiated and replace them with proper
> error reporting at realize time. This allows us to remove FW_CFG_NAME and
> FW_CFG_PATH since they are no longer required.
> 
> Signed-off-by: Mark Cave-Ayland <address@hidden>
> ---
>  hw/nvram/fw_cfg.c |   41 +++++++++++++++++++++++++++++------------
>  1 file changed, 29 insertions(+), 12 deletions(-)
> 
> diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
> index 2291121..31029ac 100644
> --- a/hw/nvram/fw_cfg.c
> +++ b/hw/nvram/fw_cfg.c
> @@ -37,9 +37,6 @@
>  
>  #define FW_CFG_FILE_SLOTS_DFLT 0x20
>  
> -#define FW_CFG_NAME "fw_cfg"
> -#define FW_CFG_PATH "/machine/" FW_CFG_NAME
> -
>  #define TYPE_FW_CFG     "fw_cfg"
>  #define TYPE_FW_CFG_IO  "fw_cfg_io"
>  #define TYPE_FW_CFG_MEM "fw_cfg_mem"
> @@ -920,19 +917,22 @@ static int fw_cfg_unattached_at_realize(void)
>  }
>  
>  
> -static void fw_cfg_init1(DeviceState *dev)
> +static void fw_cfg_common_realize(DeviceState *dev, Error **errp)
>  {
>      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);
> -
> -    qdev_init_nofail(dev);
> +    if (!fw_cfg_find()) {
maybe add comment that here, that fw_cfg_find() will return NULL if more than
1 device is found.


> +        error_setg(errp, "at most one %s device is permitted", TYPE_FW_CFG);
s/TYPE_FW_CFG/object_get_typename()/
so it would print leaf type name 

> +        return;
> +    }
>  
> -    assert(!fw_cfg_unattached_at_realize());
> +    if (fw_cfg_unattached_at_realize()) {
as I pointed out in v6, this condition will always be false,
I suggest to drop 4/6 patch and this hunk here so it won't to confuse
readers with assumption that condition might succeed.


> +        error_setg(errp, "%s device must be added as a child device before "
> +                   "realize", TYPE_FW_CFG);
> +        return;
> +    }
>  
>      fw_cfg_add_bytes(s, FW_CFG_SIGNATURE, (char *)"QEMU", 4);
>      fw_cfg_add_bytes(s, FW_CFG_UUID, &qemu_uuid, 16);
> @@ -965,7 +965,9 @@ FWCfgState *fw_cfg_init_io_dma(uint32_t iobase, uint32_t 
> dma_iobase,
>          qdev_prop_set_bit(dev, "dma_enabled", false);
>      }
>  
> -    fw_cfg_init1(dev);
> +    object_property_add_child(OBJECT(qdev_get_machine()), TYPE_FW_CFG,
> +                              OBJECT(dev), NULL);
> +    qdev_init_nofail(dev);
>  
>      sbd = SYS_BUS_DEVICE(dev);
>      ios = FW_CFG_IO(dev);
> @@ -1003,7 +1005,9 @@ FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
>          qdev_prop_set_bit(dev, "dma_enabled", false);
>      }
>  
> -    fw_cfg_init1(dev);
> +    object_property_add_child(OBJECT(qdev_get_machine()), TYPE_FW_CFG,
> +                              OBJECT(dev), NULL);
> +    qdev_init_nofail(dev);
>  
>      sbd = SYS_BUS_DEVICE(dev);
>      sysbus_mmio_map(sbd, 0, ctl_addr);
> @@ -1033,6 +1037,7 @@ FWCfgState *fw_cfg_find(void)
>      return FW_CFG(object_resolve_path_type("", TYPE_FW_CFG, NULL));
>  }
>  
> +
>  static void fw_cfg_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -1104,6 +1109,12 @@ static void fw_cfg_io_realize(DeviceState *dev, Error 
> **errp)
>                                &fw_cfg_dma_mem_ops, FW_CFG(s), "fwcfg.dma",
>                                sizeof(dma_addr_t));
>      }
> +
> +    fw_cfg_common_realize(dev, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
>  }
>  
>  static void fw_cfg_io_class_init(ObjectClass *klass, void *data)
> @@ -1170,6 +1181,12 @@ static void fw_cfg_mem_realize(DeviceState *dev, Error 
> **errp)
>                                sizeof(dma_addr_t));
>          sysbus_init_mmio(sbd, &FW_CFG(s)->dma_iomem);
>      }
> +
> +    fw_cfg_common_realize(dev, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
>  }
>  
>  static void fw_cfg_mem_class_init(ObjectClass *klass, void *data)
patch looks good, with above comments fixed:

Reviewed-by: Igor Mammedov <address@hidden>