On Thu, Jan 27, 2022 at 04:05:19 +0000, M, Shivakumar wrote:

Hello,

Hi, note that there's no need to CC both libvir-list and libvirt-users maling lists.

For our use-case with Libvirt we want to create the Memory backend object ,

Expected QEMU args would be -object memory-backend-memfd,id=mem1,size=4096M

Your description is a bit vague. Do you want to use it to back the guest memory? As by itself a memory object itself is useless without being attached somewhere In case you want to configure qemu to back the default memory of the VM by a memfd: Per https://www.libvirt.org/formatdomain.html#memory-backing <domain type='kvm'> ... <memoryBacking> <source type='memfd'/> </memoryBacking> ... </domain> Results into invoking qemu with: -machine pc-i440fx-2.9,usb=off,vmport=off,dump-guest-core=off,memory-backend=pc.ram \ ... -object '{"qom-type":"memory-backend-memfd","id":"pc.ram","x-use-canonical-path-for-ramblock-id":false,"size":1048576000,"host-nodes":[0],"policy":"bind"}' \

Request you to please help us to specify this arg in the libvirt XML.

Thanks, Shiv