On 10/19/2012 07:48 PM, Blue Swirl wrote:
DIMMs would be allowed to be hotplugged in the generic mem-controller scheme only (unless it makes sense to allow hotplug in the remaining pmc DRBs and start using the generic scheme once we run out of emulated DRBs)
440fx seems a lost cause, so we can go wild and just implement pv dimms.
Maybe. But what would be a PV DIMM? Do we need any DIMM-like granularity at all, instead the guest could be told to use a list of RAM regions with arbitrary start and end addresses?
Guests are likely to support something that has the same constraints as real hardware. If we allow non-power-of-two DIMMs, we might find that guests don't support them well.
Isn't ballooning also related?
It is related in that it is also a memory hotplug technology. But ballooning is subtractive and fine-grained where classic hotplug is additive and coarse grained. We can use both together, but I don't think any work is needed at the qemu level.
For q35 I'd like to stay within the spec.
That may not last forever when machines have terabytes of memory.
At least there's work for chipset implementers. Or we can do PV-DIMMs for q35 too.