QEMU virt (arm64) does not honor reserved-memory set in device tree

[Mohd Yusuf Abdul Hamid]

Hi,

I am trying to reserve a portion of the system memory in QEMU (arm64 virt), v7.2.1 - but the kernel never honors the reserved memory area and keeps using the area.

Say, I dumped out DTB and added:

reserved-memory {
  #address-cells = <0x02>;
  #size-cells = <0x02>;

  rsvdram@50000000 {
  no-map;
  reg = <0x00 0x50000000 0x00 0x20000000>;
  };
};

When booted, /proc/iomem still shows the kernel is using the entire space - eg 2GB. 

Is this a supported feature or I would need to modify the virt.c and define scratch area for some device driver scratch area.

Mohd Yusuf Abdul Hamid