Ingo Molnar wrote: > another small detail is that currently KVM_SET_MEMORY_REGION appears to > be an add-only interface - it is not possible to 'unregister' RAM from a > VM. >
Well, the _interface_ supports removing, the implementation does not :) Everything was written in mind to allow memory hotplug. > That keeps things easy for now, but if it's ever implemented then the > current cr3 of all vcpus of the VM needs to be validated against the > reduced memory slot map. (besides migrating all existing mappings from > the removed memory slot to other memory slots and redirecting all > in-flight DMA transactions, etc., etc. Which all needs heavy guest-OS > awareness as well.) > Actually I think it's quite easy: - halt all vcpus - wait for dma to complete - mmu_free_roots() - zap all page tables - actually unplug memory - mmu_alloc_roots() The guest needs to cooperate, but it can do so using the native memory hotlpug mechanisms (whatever they are). No guest modifications are needed. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
