Re: [RFC PATCH 11/17] hw/sd: Add eMMC support

[Jerome Forissier]

Hi Cédric,

On 3/18/22 14:28, Cédric Le Goater wrote:
> The initial eMMC support from Vincent Palatin was largely reworked to
> match the current SD framework. The parameters mimick a real 4GB eMMC,
> but it can be set to various sizes.
> 
> This adds a new QOM object class for EMMC devices.

That is interesting. Is RPMB emulation implemented? I doesn't look like
so, although...


> +    sd->ext_csd[EXT_CSD_RPMB_MULT] = 0x1; /* RPMB size */

...this indicates that the device has one block (128 KB) of RPMB if I'm
not mistaken.


I would be quite interested in testing and possibly helping out
implement RPMB, although I must admit don't know much about QEMU
internals. I have written some quick & dirty emulation code for RPMB at
the Linux ioctl() level, see [1]. This code is useful for CI testing of
the OP-TEE OS project [2], but having a lower level emulation in QEMU
would be much better since the Linux kernel would "see" the device and
report it in sysfs etc.

[1] 
https://github.com/OP-TEE/optee_client/blob/3.16.0/tee-supplicant/src/rpmb.c#L494-L571
[2] https://github.com/OP-TEE/optee_os/

Thanks,
-- 
Jerome