The reason why it behaves differently with machine types <= 2.4 is that - up to and including qemu-2.4, the calculation of the DIMM hotplug area was incorrect, - in 2.5, the calculation was fixed, - but for the migration compatibility of machine types <= 2.4, the old calculation was preserved for those machine types (the DIMM hotplug area is guest-visible)
See the following (adjacent) commits: - 3385e8e2640e ("pc: memhotplug: fix incorrectly set reserved-memory-end", 2015-09-10) - 2f8b50083b32 ("pc: memhotplug: keep reserved-memory-end broken on 2.4 and earlier machines", 2015-09-10) These commits were first released in v2.5.0. I'll look at your logs now. -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1685242 Title: ovmf hangs at efi with virtio-net memory hotplug Status in QEMU: New Bug description: with qemu 2.9 it hangs at the efi stage when memory-hotplug is enabled and it has a virtio-net devices the ovmf images where compiled from https://github.com/tianocore/edk2 (current master) reproducer: qemu-system-x86_64 -drive 'if=pflash,unit=0,format=raw,readonly,file=./OVMF_CODE.fd' -drive 'if=pflash,unit=1,format=raw,file=./my_OVMF_VARS.fd' -smp 1 -vga std -netdev 'type=tap,id=mynet' -device 'virtio-net-pci,netdev=mynet' -display sdl -nodefaults -m 'size=1G,slots=256,maxmem=1024G' interestingly, it works when you do the following: - omit the virtio-net-pci device - use seabios - use less maxmem, e.g. 512G qemu was compiled from source (v2.9.0) with following options: ./configure --target-list=x86_64-softmmu --disable-xen --enable-gnutls --enable-sdl --enable-linux-aio --enable-rbd --enable-libiscsi --disable-smartcard --audio-drv-list="alsa" --enable -spice --enable-usb-redir --enable-glusterfs --enable-libusb --disable-gtk --enable-xfsctl --enable-numa --disable-strip --enable-jemalloc --enable-virtfs --disable-libnfs --disable-fdt --disable-guest-agent --disable-guest-agent-msi To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1685242/+subscriptions