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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/1] Xen PV support for hugepages
>>> Dave McCracken <dcm@xxxxxxxx> 06.11.08 14:44 >>> >> Finally, no longer hiding X86_FEATURE_PSE from the guest seems rather >> risky: I'm pretty sure the pv-ops kernel relies on this flag being clear - >> when set, it would blindly (i.e. without ensuring the underlying memory is >> contiguous and suitably aligned) try to use 2Mb mappings for e.g. the 1:1 >> mapping. I would think this capability ought to be propagated by another >> means. Likewise I'm uncertain about letting X86_CR4_PSE shine through. >> >> And a general question: How is a trivial DomU going to be able to make >> use of this, without being permitted to allocate non-order-zero chunks of >> memory? > >This is the point of having hugepages a command line option. It should only >be turned on if you intend to run guests who enforce the alignment rules. You mean 'if you intend to run *only* guests ...', including dom0. Any guest unaware of the connection of X86_FEATURE_PSE and the need to create contiguous 2M chunks would fail, and any guest not having I/O memory assigned would never manage to create such chunks. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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