[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] NPT and EPT question
Hi, At 21:23 +0800 on 17 Nov (1226957017), bo ma wrote: > Recent I read AMD specification about NPT,and met with a question about a > sentence. > > The sentence is : Note that host table walks for guest page tables are > always treated as data writes.I don't know why treated as data writes? Possibly because the guest-table walker might have to set the A and D bits, and the hardware doesn't know whether it will do that until _after_ it's done the host-table walk. Maybe someone from AMD can clarify. > In intel EPT ,is it the same? or treated as data reads? My impression is that EPT only requires write permissions if it actually writes back an A or D bit, but I'm not sure. It should be easy to check. Cheers, Tim -- Tim Deegan <Tim.Deegan@xxxxxxxxxx> Principal Software Engineer, Citrix Systems (R&D) Ltd. [Company #02300071, SL9 0DZ, UK.] _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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