Query regarding hole in EFI Memory Map

["Prakhya, Sai Praneeth" <sai.praneeth.prakhya@intel.com>]

Hi All,

Recently, I have observed that there was a hole in EFI Memory Map passed by firmware to Linux kernel. So, wanted to check with you if this is expected or not.

My Test setup:
I usually boot qemu with OVMF and Linux kernel. I use below command to boot kernel.
"qemu-system-x86_64 -cpu host -hda <live-image> -serial stdio -bios <OVMF.fd> -m 2G -enable-kvm -smp 2"

I have noticed that the EFI Memory Map (printed by kernel) is almost contiguous but with only one hole ranging from 0xA0000 to 0x100000. As far as I know, kernel hasn't modified this EFI Memory Map, so I am assuming that firmware has passed memory map with a hole. I have looked at UEFI spec "GetMemoryMap()" definition, and it says "The map describes all of memory, no matter how it is being used". So, I am thinking that EFI Memory Map shouldn't have any holes, am I correct? If not, could someone please explain me the reason for this hole in EFI Memory Map.



Please let me know if you want me to post the EFI Memory Map or E820 map that I am looking at.

Note: I have also observed the same hole in E820 map.



Regards,

Sai