KVM: x86/mmu: Move shadow-present check out of spte_has_volatile_bits()
Move the is_shadow_present_pte() check out of spte_has_volatile_bits()
and into its callers. Well, caller, since only one of its two callers
doesn't already do the shadow-present check.
Opportunistically move the helper to spte.c/h so that it can be used by
the TDP MMU, which is also the primary motivation for the shadow-present
change. Unlike the legacy MMU, the TDP MMU uses a single path for clear
leaf and non-leaf SPTEs, and to avoid unnecessary atomic updates, the TDP
MMU will need to check is_last_spte() prior to calling
spte_has_volatile_bits(), and calling is_last_spte() without first
calling is_shadow_present_spte() is at best odd, and at worst a violation
of KVM's loosely defines SPTE rules.
Note, mmu_spte_clear_track_bits() could likely skip the write entirely
for SPTEs that are not shadow-present. Leave that cleanup for a future
patch to avoid introducing a functional change, and because the
shadow-present check can likely be moved further up the stack, e.g.
drop_large_spte() appears to be the only path that doesn't already
explicitly check for a shadow-present SPTE.
No functional change intended.
Signed-off-by: Sean Christopherson <email@example.com>
Signed-off-by: Paolo Bonzini <firstname.lastname@example.org>
3 files changed