qemu/docs/memory-hotplug.txt

29 Creates a guest with 1GB of memory and three hotpluggable memory slots.
31 memory the guest will see after boot is 1GB. The maximum memory the
32 guest can reach is 4GB. This means that three additional gigabytes can be
41 For example, the following commands add another 1GB to the guest
54 For example, assuming that the host has 1GB hugepages available in
55 the /mnt/hugepages-1GB directory, a 1GB hugepage could be hotplugged
58   (qemu) object_add memory-backend-file,id=mem1,size=1G,mem-path=/mnt/hugepages-1GB
65 In the following command-line example, an 8GB guest is created where 6GB
66 comes from regular RAM, 1GB is a 1GB hugepage page and 256MB is from
67 2MB pages. Also, the guest has additional memory slots to hotplug more
68 2GB if needed:
70  qemu [...] -m 6GB,slots=4,maxmem=10G \
73    -object memory-backend-file,id=mem2,size=256M,mem-path=/mnt/hugepages-2MB \