> > In addition to the suggestions above, I'd suggest breaking this patch > > up, since it is doing multiple things: > > > > 1. Patch initialize shadow page tables to EMPTY_SPTE (0) and > > replace TDP MMU hard-coded 0 with EMPTY_SPTE. > > 2. Patch to change FNAME(sync_page) to not assume EMPTY_SPTE is 0. > > 3. Patch to set bit 63 in EMPTY_SPTE. > > 4. Patch to set bit 63 in REMOVED_SPTE. I think 1/2 can be separate patches, but 3/4 should be done together. Patch 3 alone is broken as when TDP MMU zaps SPTE and replaces it with REMOVED_SPTE, it loses bit 63. This is not what we want. We always want bit 63 set if it is supposed to be set to a non-present SPTE. But I also don't see splitting to 3 patches is absolutely worth to do as doing above in one patch is also fine to me.
