[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [Patch 2/4] Refining Xsave/Xrestore support
>>> On 28.10.10 at 10:33, Haitao Shan <maillists.shan@xxxxxxxxx> wrote: > I once considered this problem, too. Originally, I suppose I can use > CR4 switching when entering/leaving PV guest, as what HW is doing for > us in VMX. But I suspect this will bring a lot of overhead. > Later I picked the current implementation, hoping guest applications > can have a check on XCR0 first before it uses extended states. And > according to spec, in order to use extend states, XCR0 must be set, > but this is a ring 0 instruction only. Ah, yes, that's correct of course. So I guess pv-ops could use the CPUID.OSXSAVE approach then, too. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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