On 1/12/24 21:37, Dave Hansen wrote: > On 1/12/24 12:28, Tom Lendacky wrote: >> I thought there was also a desire to remove the direct map for any pages >> assigned to a guest as private, not just the case that the comment says. >> So updating the comment would probably the best action. > > I'm not sure who desires that. > > It's sloooooooow to remove things from the direct map. There's almost > certainly a frequency cutoff where running the whole direct mapping as > 4k is better than the cost of mapping/unmapping. > > Actually, where _is_ the TLB flushing here? Hm yeah it seems to be using the _noflush version? Maybe the RMP issues this avoids are only triggered with actual page tables and a stray outdated TLB hit doesn't trigger it? Needs documenting though if that's the case.
