KVM: MMU: simplify last_pte_bitmap
Branch-free code is fun and everybody knows how much Avi loves it,
but last_pte_bitmap takes it a bit to the extreme. Since the code
is simply doing a range check, like
(level == 1 ||
((gpte & PT_PAGE_SIZE_MASK) && level < N)
we can make it branch-free without storing the entire truth table;
it is enough to cache N.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1c3e390..d110dc4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -347,12 +347,8 @@
struct rsvd_bits_validate guest_rsvd_check;
- /*
- * Bitmap: bit set = last pte in walk
- * index[0:1]: level (zero-based)
- * index[2]: pte.ps
- */
- u8 last_pte_bitmap;
+ /* Can have large pages at levels 2..last_nonleaf_level-1. */
+ u8 last_nonleaf_level;
bool nx;