Zachary Amsden wrote: > Nakajima, Jun wrote: > > And actually you don't need the write to CR3 to flush TLB because the > > one to CR4 does it. Or does kvm_flush_tlb_kernel assume that CR3 is updated > > at the same time? > > > > Jun > > It should not be necessary, but I believe this was added as a workaround > to a PII erratum. I can't find the erratum, however, and the history of > using G bits in Linux is complicated (several bugs introduced and many > intermediate versions of this code). Since this is not performance > critical, I think it is probably best to leave the CR3 reload.
I don't recommend this for old processors. > > However, being unnecessary on modern processors, I already submitted a > patch to eliminate it on 64-bit (or maybe just told Andi about it, I > can't recall). > > Zach For KVM, it should be okay as well. But we can replace two CR4 accesses with just one hypercall. Jun --- Intel Open Source Technology Center ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
