Re: [PATCH 2/5] s390x: Add loadparm to CcwDevice

[Thomas Huth]

On 29/05/2024 17.43, jrossi@linux.ibm.com wrote:
> From: Jared Rossi <jrossi@linux.ibm.com>
>
> Add a loadparm property to the CcwDevice object so that different loadparms
> can be defined on a per-device basis when using multiple boot devices.
>
> The machine/global loadparm is still supported. If both a global and per-device
> loadparm are defined, the per-device value will override the global value for
> that device, but any other devices that do not specify a per-device loadparm
> will still use the global loadparm.
>
> Assigning a loadparm to a non-boot device is invalid and will be rejected.
>
> Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
> ---
...
> diff --git a/hw/s390x/ccw-device.c b/hw/s390x/ccw-device.c
> index fb8c1acc64..143e085279 100644
> --- a/hw/s390x/ccw-device.c
> +++ b/hw/s390x/ccw-device.c
> @@ -13,6 +13,10 @@
>   #include "ccw-device.h"
>   #include "hw/qdev-properties.h"
>   #include "qemu/module.h"
> +#include "ipl.h"
> +#include "qapi/visitor.h"
> +#include "qemu/ctype.h"
> +#include "qapi/error.h"
>   
>   static void ccw_device_refill_ids(CcwDevice *dev)
>   {
> @@ -36,10 +40,55 @@ static void ccw_device_realize(CcwDevice *dev, Error **errp)
>       ccw_device_refill_ids(dev);
>   }
>   
> +static void ccw_device_get_loadparm(Object *obj, Visitor *v,
> +                                 const char *name, void *opaque,
> +                                 Error **errp)
> +{
> +    CcwDevice *dev = CCW_DEVICE(obj);
> +    char *str = g_strndup((char *) dev->loadparm, sizeof(dev->loadparm));
> +
> +    visit_type_str(v, name, &str, errp);
> +    g_free(str);
> +}
> +
> +static void ccw_device_set_loadparm(Object *obj, Visitor *v,
> +                                 const char *name, void *opaque,
> +                                 Error **errp)
> +{
> +    CcwDevice *dev = CCW_DEVICE(obj);
> +    char *val;
> +    int index;
> +
> +    index = object_property_get_int(obj, "bootindex", &error_abort);

The error_abort is rather unfortunate here, it can be used to terminate QEMU 
unexpectedly:

$ ./qemu-system-s390x -no-shutdown -nographic -serial none -monitor stdio
QEMU 9.0.50 monitor - type 'help' for more information
(qemu) device_add virtio-rng-ccw,loadparm=1
Unexpected error in object_property_find_err() at 
../../devel/qemu/qom/object.c:1358:
Property 'virtio-rng-ccw.bootindex' not found
Aborted (core dumped)

Since you check for the error via "index" afterwards anyway, I think it's 
likely ok to replace &error_abort with NULL here.

But apart from that, it's also a bit ugly that each and every ccw device 
gets a loadparm property now. Would it be possible to add it to the devices 
that can be used for booting only?

 Thomas