On Mon, Oct 14, 2024 at 04:46:12PM +0200, David Hildenbrand wrote: > Let's finally add s390 support for virtio-mem; my last RFC was sent > 4 years ago, and a lot changed in the meantime. > > The latest QEMU series is available at [1], which contains some more > details and a usage example on s390 (last patch). > > There is not too much in here: The biggest part is querying a new diag(500) > STORAGE_LIMIT hypercall to obtain the proper "max_physmem_end". > > The last two patches are not strictly required but certainly nice-to-have. > > Note that -- in contrast to standby memory -- virtio-mem memory must be > configured to be automatically onlined as soon as hotplugged. The easiest > approach is using the "memhp_default_state=" kernel parameter or by using > proper udev rules. More details can be found at [2]. > > I have reviving+upstreaming a systemd service to handle configuring > that on my todo list, but for some reason I keep getting distracted ... > > I tested various things, including: > * Various memory hotplug/hotunplug combinations > * Device hotplug/hotunplug > * /proc/iomem output > * reboot > * kexec > * kdump: make sure we don't hotplug memory > > One remaining work item is kdump support for virtio-mem memory. This will > be sent out separately once initial support landed. Besides the open kdump question, which I think is quite important, how is this supposed to go upstream? This could go via s390, however in any case this needs reviews and/or Acks from kvm folks.
