Xen x86/paging, x86/cpu など修正MEMO

[Xen-changelog] [xen stable-4.4] x86/paging: make log-dirty operations preemptible
http://lists.xen.org/archives/html/xen-changelog/2014-08/msg00078.html

なんか複雑そうね。

 [Xen-changelog] [xen master] Revert "x86/paging: make log-dirty operations preemptible"
 http://lists.xen.org/archives/html/xen-changelog/2014-08/msg00083.html
 This fix has been discovered to cause regressions.  Investigations are ongoing.

[Xen-changelog] [xen stable-4.4] x86/cpu: undo BIOS CPUID max_leaf limit before querying for features
http://lists.xen.org/archives/html/xen-changelog/2014-08/msg00065.html

 If IA32_MISC_ENABLE[22] is set by the BIOS, CPUID.0.EAX will be limited to 3.
 Lift this limit before considering whether to query CPUID.7[ECX=0].EBX for features.