On 2013-02-11 13:49, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > 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 > I suppose they do not apply anymore as well. Do you have a recent tree around somewhere or plan to resume work on it? Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- 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
