>>> On 03.04.19 at 20:32, <andrew.coop...@citrix.com> wrote: > On 13/03/2019 12:39, Jan Beulich wrote: >> While the mere updating of ->pv_cr3 and ->root_pgt_changed aren't overly >> expensive (but still needed only for the toggle_guest_mode() path), the >> effect of the latter on the exit-to-guest path is not insignificant. >> Move the logic into toggle_guest_mode(). >> >> Signed-off-by: Jan Beulich <jbeul...@suse.com> > > What case does this make faster? I'm really struggling to see how this > is safe.
The two cases where toggle_guest_pt() gets called (and then in pairs): Since we know we're going to switch back to the original page tables (other than when coming through toggle_guest_mode()), there's no need to request any special exit-to-guest processing by setting root_pgt_changed. Imo it was wrong in the first place to have this code added to _toggle_guest_pt(). The separation of the two functions was specifically done so that things only affecting a mode switch would go into toggle_guest_mode(), not the common helper. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
