Avi Kivity wrote: > Dong, Eddie wrote: >>> There's a two-liner required to make it work. I'll add it soon. >>> >>> >> But you still needs to issue WBINVD to all pCPUs which just move >> non-response time from one place to another, not? >> > > You don't actually need to emulate wbinvd, you can just ignore it. > > The only reason I can think of to use wbinvd is if you're taking a cpu > down (for a deep sleep state, or if you're shutting it off). A guest > need not do that. > > Any other reason? dma? all dma today is cache-coherent, no? > For legacy PCI device, yes it is cache-cohetent, but for PCIe devices, it is no longer a must. A PCIe device may not generate snoopy cycle and thus require OS to flush cache.
For example, a guest with direct device, say audio, can copy data to dma buffer and then wbinvd to flush cache out and ask HW DMA to output. Thx,Eddie ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
