Messages in this thread | | | Date | Thu, 4 Mar 2010 11:42:55 -0300 | From | Marcelo Tosatti <> | Subject | Re: [PATCH 0/18][RFC] Nested Paging support for Nested SVM (aka NPT-Virtualization) |
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On Wed, Mar 03, 2010 at 08:12:03PM +0100, Joerg Roedel wrote: > Hi, > > here are the patches that implement nested paging support for nested > svm. They are somewhat intrusive to the soft-mmu so I post them as RFC > in the first round to get feedback about the general direction of the > changes. Nevertheless I am proud to report that with these patches the > famous kernel-compile benchmark runs only 4% slower in the l2 guest as > in the l1 guest when l2 is single-processor. With SMP guests the > situation is very different. The more vcpus the guest has the more is > the performance drop from l1 to l2. > Anyway, this post is to get feedback about the overall concept of these > patches. Please review and give feedback :-)
Joerg,
What perf gain does this bring ? (i'm not aware of the current overhead).
Overall comments:
Can't you translate l2_gpa -> l1_gpa walking the current l1 nested pagetable, and pass that to the kvm tdp fault path (with the correct context setup)?
You probably need to include a flag in base_role to differentiate between l1 / l2 shadow tables (say if they use the same cr3 value).
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