On Wed, Sep 02, 2009 at 05:57:39PM +0200, Alexander Graf wrote: > > Am 02.09.2009 um 17:38 schrieb oritw@xxxxxxxxxx: > >> The following patches implement nested VMX support. The patches >> enable a guest to use the VMX APIs in order to run its own nested >> guest (i.e., enable running other hypervisors which use VMX under >> KVM). > > Copl! Great job here. I was expecting vmcs load/stores to kill > performance, but apparently I was wrong. How did you get those fast? Are you asking about vmptrld (switching the VMCS's) or the costs of trapping vmread/vmwrites? >> The current patches support running Linux under a nested KVM using >> shadow page table (with bypass_guest_pf disabled). > > What is keeping you from running the other hypervisors, guests? A simple matter of programming (or more accurately, debugging). There are no fundamental limitations that preclude running other hypervisors or multiple guests, but we've been concentrating on getting a single hypervisor (both KVM and VMware) performing well first. >> SMP support was fixed. Reworking EPT support to mesh cleanly with >> the current shadow paging design per Avi's comments is a >> work-in-progress. >> >> The current patches only support a single nested hypervisor > > Why? See above---no fundamental limitation---but needs more work. Bug reports happily accepted, patches even more so :-) >> , which can only run a single guest (multiple guests are work in >> progress). Only 64-bit nested hypervisors are supported. >> >> Additional patches for running Windows under nested KVM, and Linux >> under nested VMware server(!), > > GSX or ESX? With ESX I was running into TSC timing issues because > ESX didn't like the fact it got preempted :-). GSX. I expect the issues you've run into are not SVM specific, so likely they'll need to be address for VMX as well. > How about Hyper-V and Xen? We haven't tried them. > Again, great job and congratulations on making this work! Thank you, your patches were very useful! Cheers, Muli -- Muli Ben-Yehuda | muli@xxxxxxxxxx | +972-4-8281080 Manager, Virtualization and Systems Architecture Master Inventor, IBM Haifa Research Laboratory -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
