On Fri, Oct 23, 2020 at 10:43 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 23/10/20 19:23, Jim Mattson wrote: > >> The information that we need is _not_ that provided by the advanced > >> VM-exit information (or by a page walk). If a page is neither writable > >> nor executable, the advanced information doesn't say if the injected #PF > >> should be a W=1 or a F=1 fault. We need the information in bits 0..2 of > >> the exit qualification for the final access, which however is not > >> available for the paging-structure access. > >> > > Are you planning to extend the emulator, then, to support all > > instructions? I'm not sure where you are going with this. > > I'm going to fix the bit 8=1 case, but for bit 8=0 there's not much that > you can do. In all likelihood the guest is buggy anyway. Did this drop off your radar? Are you still planning to fix the bit8=1 case to use advanced EPT exit qualification information? Or did I just miss it? > It would be possible to only do the decode part of the emulator to get > the PFEC (matching the GVA from the vmexit to the memory operand, for > example, and retrying if the instruction is unexpected). Then one would > only need enough VEX/EVEX parsing to process the decoding. > > Paolo >
