On Thu, Oct 21, 2021 at 10:13 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 21/10/21 16:52, Sean Christopherson wrote: > >> I think the EPT violation happens*after* the cr3 write. So the instruction to be > >> emulated is not "cr3 write". The emulation will queue fault into guest though, > >> recursive EPT violation happens since the cr3 exceeds maxphyaddr limit. > > Doh, you're correct. I think my mind wandered into thinking about what would > > happen with PDPTRs and forgot to get back to normal MOV CR3. > > > > So yeah, the only way to correctly handle this would be to intercept CR3 loads. > > I'm guessing that would have a noticeable impact on guest performance. > > Ouch... yeah, allow_smaller_maxphyaddr already has bad performance, but > intercepting CR3 loads would be another kind of slow. Can we kill it? It's only half-baked as it is. Or are we committed to it now?
