On 11/05/2010 06:31 PM, Gleb Natapov wrote: > On Fri, Nov 05, 2010 at 04:03:28PM +0800, Xiao Guangrong wrote: >> On 11/05/2010 03:45 PM, Gleb Natapov wrote: >> >>>> >>>> It looks like something broken: apfs can generated in L2 guest (nested ntp guest) >>>> and be retried in L1 guest. >>>> >>> Why is this a problem? apf will be generate on direct map even when L2 >>> guest is running so it should be OK to prefault it into direct map on >>> completion. >>> >> >> The nested_cr3 is different between L2 and L1, fix L2's page fault in L1's page table >> is useless. > But we are fixing L0 page faults in L0 page table. We do not start apf > because of L1 faulted in its page table. > Hi Gleb, For example, NPT Guest L1 runs on Host, and Nested NPT Guest L2 runs on Guest L1. Now, Guest L2 is running, has below sequences: a: NPF/PF occurs in L2 Guest, and generates a apf(named A-apf), then L2 Guest is blocked b: a external event wakes up L2 Guest, and let it run again. c: L2 Guest VMEXIT to L1 Guest because L2 Guest's action is intercepted by Guest L1 d: When cpu enter L1 Guest, A-apf is completed, then it will retry A-apf in L1 Guest's mmu context, and this 'retry' is useless. Could you please point it out for me if i missed something. :-) -- 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
