Re: [Qemu-devel] [PATCH V2 10/10] hw/sd.c: introduce SD card "image" property and allow SD hot-insert

[Paolo Bonzini]

Il 05/04/2012 17:48, Igor Mitsyanko ha scritto:
> New SD card "image" property can be used to:
> - change image file attached to virtual SD card
> - hot-insert new image file into newly initialized BlockDriverState (this was 
> not
> possible before).
> 
> Example usage:
> ./qom-set /machine/milkymist/milkymist-memcard/card.image 
> /home/me/mynewcard.img
> this will attach image file /home/me/mynewcard.img to virtual SD card 
> connected to
> milkymist-memcard host controller device. If virtual card was already 
> attached to
> some other image file, eject event is triggered before attaching new file.
> 
> Signed-off-by: Igor Mitsyanko <address@hidden>
> ---
>  hw/sd.c |   44 ++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 44 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/sd.c b/hw/sd.c
> index 8ffaa17..3e75405 100644
> --- a/hw/sd.c
> +++ b/hw/sd.c
> @@ -1816,6 +1816,48 @@ static void sd_set_spimode(Object *obj, Visitor *v, 
> void *opaque,
>      }
>  }
>  
> +static void sd_set_image_path(Object *obj, Visitor *v, void *opaque,
> +                         const char *name, Error **errp)
> +{
> +    SDState *sd = SD_CARD(obj);
> +    char *new_image;
> +
> +    visit_type_str(v, &new_image, "file", errp);

Please use the name argument instead of "file".

> +
> +    if (error_is_set(errp)) {
> +        return;
> +    }
> +
> +    if (sd->bdrv) {
> +        qmp_change_blockdev(bdrv_get_device_name(sd->bdrv), new_image,
> +                false, NULL, errp);
> +    } else {
> +        DriveInfo *di;
> +        QemuOpts *opts = drive_add(IF_SD, sd->if_idx, new_image, "");

I think this should simply take a drive name and pass it to
bdrv_get_device_name.  The drive_add/drive_init should be done
separately with the drive_add monitor command, like

drive_add 0 file=foo.img,if=none,id=bar

With the upcoming support for static properties in objects that are not
devices, you can just add a drive property to the SD class.

There is a problem here however.  QOM commands are HMP only, and
drive_add is QMP only.  I think that blocking drive_add in QMP is
perfect being the enemy of good.  Alternatively, however, adding the QOM
property commands to HMP would also make sense.

Paolo