Re: [PATCH v5 2/6] hw/sd/sdcard: Allow user-instantiated eMMC

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 27/10/25 12:55, Daniel P. Berrangé wrote:
> On Fri, Oct 17, 2025 at 02:03:54PM +0200, Jan Kiszka wrote:
>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>
>> Enable user-instantiation so that PCI-attached eMMCs can be created for
>> virt machines, for QA purposes for the eMMC model itself and for complex
>> firmware/OS integrations using the upcoming RPMB partition support.
> 
> IIUC, the 'emmc' device wants an 'sd-bus' but this commit talks about
> it being PCI-attached ?

Sigh, it should not, but it got introduced this way and we didn't
have time / energy / good reason to rework the code, which currently
just works.

SD / MMC cards -> plugged over external SD bus

embedded MMC cards -> no SD bus, directly mmio-mapped.

> 
> Can you elaborate on / illustrate the usage example for an end user ?

Saving time by testing virtual hardware, without having to implement a
real model.

Personally I'm not in favor of modelling unspecified devices (IOW not
following a spec). But I can understand QEMU usefulness with fast
HW prototyping.

> 
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>   hw/sd/sd.c | 2 --
>>   1 file changed, 2 deletions(-)
>>
>> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
>> index d1e1bb4f0e..305ea251cb 100644
>> --- a/hw/sd/sd.c
>> +++ b/hw/sd/sd.c
>> @@ -2928,8 +2928,6 @@ static void emmc_class_init(ObjectClass *klass, const void *data)
>>       dc->desc = "eMMC";
>>       dc->realize = emmc_realize;
>>       device_class_set_props(dc, emmc_properties);
>> -    /* Reason: Soldered on board */
>> -    dc->user_creatable = false;
>>   
>>       sc->proto = &sd_proto_emmc;
>>   
>> -- 
>> 2.51.0
>>
>>
> 
> With regards,
> Daniel