When guest changes MTRR/PAT, must flush cache and destroy shadow page table in xen. This can be done in do_msr_write when guest changes MTRR/PAT related MSRs. But there is a window that MTRR/PAT is different between VCPUs when changing MTRR/PAT, it may bring some troubles or incorrect. So we try another way to do it: The guest will enter no-fill cache mode(set CR0:CD/NW) befor changing MTRR/PAT, then update MTRR/PAT and exit no-fill mode. We intercept the changing of cache mode. If one of vcpu is in no-fill mode or MTRR/PAT is different between vcpus, set shadow pte as UC. When all the vcpus exit from no-fill mode, and MTRR/PAT is the same between vcpus, set shadow pte as usual. Best Regards, Disheng, Su _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel