SD Host Controller Spec
https://www.sdcard.org/downloads/pls/
eMMC emulation support
还未合入主线，在qemu-devel邮件列表中
[PATCH V3 00/21]eMMC support
https://lore.kernel.org/qemu-devel/1614540807-30686-1-git-send-email-sai.pavan.boddu@xilinx.com/
[RFC PATCH 00/17] hw/sd: Rework models for eMMC support
https://lore.kernel.org/qemu-devel/20220318132824.1134400-1-clg@kaod.org/
[PATCH v2 00/25] hw/sd: Rework models for eMMC support
https://lore.kernel.org/qemu-devel/20220530193816.45841-1-philippe.mathieu.daude@gmail.com/
ext4 jbd2 disk layout
https://tooson.tistory.com/1