https://bugzilla.kernel.org/show_bug.cgi?id=53611 Summary: nVMX: Add nested EPT Product: Virtualization Version: unspecified Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: kvm AssignedTo: virtualization_kvm@xxxxxxxxxxxxxxxxxxxx ReportedBy: nyh@xxxxxxxxxxxxxxxxxxx Regression: No Created an attachment (id=93101) --> (https://bugzilla.kernel.org/attachment.cgi?id=93101) Nested EPT patches, v2 Nested EPT means emulating EPT for an L1 guest, allowing it to use EPT when running a nested guest L2. When L1 uses EPT, it allows the L2 guest to set its own cr3 and take its own page faults without either of L0 or L1 getting involved. In many workloads this significanlty improves L2's performance over the previous two alternatives (shadow page tables over ept, and shadow page tables over shadow page tables). As an example, I measured a single-threaded "make", which has a lot of context switches and page faults, on the three options: shadow over shadow: 105 seconds shadow over EPT: 87 seconds (this is the default currently) EPT over EPT: 29 seconds single-level virtualization (with EPT): 25 seconds So clearly nested EPT would be a big win for such workloads. I attach a patch set which I worked on and allowed me to measure the above results. This is the same patch set I sent to KVM mailing list on August 1st, 2012, titled "nEPT v2: Nested EPT support for Nested VMX". This patch set still needs some work: it is known to only work in some setups but not others, and the file "announce" in the attached tar lists 5 things which definitely need to be done. There were a few additional comments in the mailing list - see http://comments.gmane.org/gmane.comp.emulators.kvm.devel/95395 -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- 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
