On 22/06/21 19:57, Sean Christopherson wrote:
For 32-bit paging (non-PAE), the adjustments are needed purely because bit 7 is ignored if PSE=0. Retain that logic as is, but make is_last_gpte() unique per PTTYPE
... which makes total sense given where it's used, too.
+#if PTTYPE == 32 + /* + * 32-bit paging requires special handling because bit 7 is ignored if + * CR4.PSE=0, not reserved. Clear bit 7 in the gpte if the level is + * greater than the last level for which bit 7 is the PAGE_SIZE bit. + * + * The RHS has bit 7 set iff level < (2 + PSE). If it is clear, bit 7 + * is not reserved and does not indicate a large page at this level, + * so clear PT_PAGE_SIZE_MASK in gpte if that is the case. + */ + gpte &= level - (PT32_ROOT_LEVEL + !!mmu->mmu_role.ext.cr4_pse);
!! is not needed and possibly slightly confusing? (We know it's a single bit).
Paolo
