Re: [PATCH 2/2] arm: xlnx-versal-virt: Add machine property ospi-flash

[Peter Maydell]

On Tue, 5 Dec 2023 at 09:52, Sai Pavan Boddu <sai.pavan.boddu@amd.com> wrote:
>
> This property allows users to change flash model on command line as
> below.
>
>    ex: "-M xlnx-versal-virt,ospi-flash=mt35xu02gbba"
>
> Signed-off-by: Sai Pavan Boddu <sai.pavan.boddu@amd.com>
> ---
>  hw/arm/xlnx-versal-virt.c | 31 ++++++++++++++++++++++++++++++-
>  1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/hw/arm/xlnx-versal-virt.c b/hw/arm/xlnx-versal-virt.c
> index 537118224f..c57cff74d8 100644
> --- a/hw/arm/xlnx-versal-virt.c
> +++ b/hw/arm/xlnx-versal-virt.c
> @@ -49,6 +49,7 @@ struct VersalVirt {
>      struct {
>          bool secure;
>      } cfg;
> +    char *ospi_model;
>  };
>
>  static void fdt_create(VersalVirt *s)
> @@ -637,6 +638,22 @@ static void sd_plugin_card(SDHCIState *sd, DriveInfo *di)
>                             &error_fatal);
>  }
>
> +static char *versal_get_ospi_model(Object *obj, Error **errp)
> +{
> +    VersalVirt *s = XLNX_VERSAL_VIRT_MACHINE(obj);
> +
> +    return g_strdup(s->ospi_model);
> +}
> +
> +static void versal_set_ospi_model(Object *obj, const char *value, Error 
> **errp)
> +{
> +    VersalVirt *s = XLNX_VERSAL_VIRT_MACHINE(obj);
> +
> +    g_free(s->ospi_model);
> +    s->ospi_model = g_strdup(value);
> +}
> +
> +
>  static void versal_virt_init(MachineState *machine)
>  {
>      VersalVirt *s = XLNX_VERSAL_VIRT_MACHINE(machine);
> @@ -736,7 +753,7 @@ static void versal_virt_init(MachineState *machine)
>
>          spi_bus = qdev_get_child_bus(DEVICE(&s->soc.pmc.iou.ospi), "spi0");
>
> -        flash_dev = qdev_new("mt35xu01g");
> +        flash_dev = qdev_new(s->ospi_model ? s->ospi_model : "mt35xu01g");
>          if (dinfo) {
>              qdev_prop_set_drive_err(flash_dev, "drive",
>                                      blk_by_legacy_dinfo(dinfo), 
> &error_fatal);

This doesn't do any checking of the string the user passes,
which means the user can make us hit an abort() with a not
terribly helpful error message:

$ ./build/arm-clang/qemu-system-aarch64 -M xlnx-versal-virt,ospi-flash=bang
qemu-system-aarch64: unknown type 'bang'
Aborted (core dumped)

or complain about trying to create an abstract type:
$ ./build/arm-clang/qemu-system-aarch64 -M
xlnx-versal-virt,ospi-flash=m25p80-generic
**
ERROR:../../qom/object.c:525:object_initialize_with_type: assertion
failed: (type->abstract == false)
Bail out! ERROR:../../qom/object.c:525:object_initialize_with_type:
assertion failed: (type->abstract == false)
Aborted (core dumped)

or do some weird stuff if you pass it something that isn't a
flash device type name:

$ ./build/arm-clang/qemu-system-aarch64 -M xlnx-versal-virt,ospi-flash=e1000
Unexpected error in object_property_find_err() at ../../qom/object.c:1330:
qemu-system-aarch64: Property 'e1000.cs' not found
Aborted (core dumped)

I think you need to check that the string corresponds
to a type that actually exists and is a subtype of TYPE_M25P80
and isn't an abstract type.

thanks
-- PMM