[Qemu-devel] Hotplug ram and vhost-user

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

Hi,
  Since I'm reworking the memory map update code I've been
trying to test it with hot adding RAM; but even on upstream
I'm finding that hot adding RAM causes the guest to stop passing
packets with vhost-user-bridge;  have either of you seen the same
thing?

I'm doing:
./tests/vhost-user-bridge -u /tmp/vubrsrc.sock
$QEMU -enable-kvm -m 1G,maxmem=2G,slots=4 -smp 2 -object memory-backend-file,id=mem,size=1G,mem-path=/dev/shm,share=on -numa node,memdev=mem -mem-prealloc -trace events=vhost-trace-file -chardev socket,id=char0,path=/tmp/vubrsrc.sock -netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce -device virtio-net-pci,netdev=mynet1 $IMAGE -net none 

(with a f27 guest) and then doing:
(qemu) object_add memory-backend-file,id=mem1,size=256M,mem-path=/dev/shm
(qemu) device_add pc-dimm,id=dimm1,memdev=mem1

but then not getting any responses inside the guest.

I can see the code sending another set-mem-table with the
extra chunk of RAM and fd, and I think I can see the bridge
mapping it.

Dave

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK