Omar Khan wrote: > Dor Laor <[EMAIL PROTECTED]> writes: > > > >> Theoretically speaking the answer is yes, vmcall is a special >> instruction that it one and only purpose is the exit from the guest. >> While mov cr3 instruction might be bound to other actions of the >> processor and might have more effects on the pipeline, this harder to >> optimize for vmexit purposes. >> >> > > I guess what is confusing me is that the vmcall causes an vmexit in VMX > non-root > mode (the one in which a paravirtualized guest is operating), but Avi says > that > a hypercal (made using a vmcall) 'avoids' a vmentry/vmexit and Ingo comments > in > his patch that : > > "This utilizes the cr3 filter capability of the hardware - if this works out > then no VM exit happens" > > NO VM-exits happen. hmmmm... maybe I need to go over the intel manuals more > thoroughly, however any hints will be most welcomed. >
Using the cr3 filter does not involve a hypercall. Instead, it allows the guest to context switch without trapping on the mov %cr3 instruction, by providing a set of pre-prepared cr3s. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kvm-devel
