On Friday 25 June 2010 16:54:19 Jan Kiszka wrote: > Sheng Yang wrote: > > Some guest device driver may leverage the "Non-Snoop" I/O, and explicitly > > WBINVD or CLFLUSH to a RAM space. Since migration may occur before WBINVD > > or CLFLUSH, we need to maintain data consistency either by: > > 1: flushing cache (wbinvd) when the guest is scheduled out if there is no > > wbinvd exit, or > > 2: execute wbinvd on all dirty physical CPUs when guest wbinvd exits. > > > > For wbinvd VMExit capable processors, we issue IPIs to all physical CPUs > > to do wbinvd, for we can't easily tell which physical CPUs are "dirty". > > wbinvd is a heavy weapon in the hands of a guest. Even if it is limited > to pass-through scenarios, do we really need to bother all physical host > CPUs with potential multi-millisecond stalls? Think of VMs only running > on a subset of CPUs (e.g. to isolate latency sources). I would suggest > to track the physical CPU usage of VCPUs between two wbinvd requests and > only send the wbinvd IPI to that set. OK, would try to make it more specific(and complex)... > > Also, I think the code is still too much vmx-focused. Only the trapping > should be vendor specific, the rest generic. OK, would consider it. -- regards Yang, Sheng > > Jan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
