exec: Use TARGET_PAGE_BITS_MIN for TLB flags

These bits do not need to vary with the actual page size
used by the guest.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

include/exec/cpu-all.h

@@ -317,20 +317,24 @@ CPUArchState *cpu_copy(CPUArchState *env);
 
 #if !defined(CONFIG_USER_ONLY)
 
-/* Flags stored in the low bits of the TLB virtual address.  These are
- * defined so that fast path ram access is all zeros.
+/*
+ * Flags stored in the low bits of the TLB virtual address.
+ * These are defined so that fast path ram access is all zeros.
  * The flags all must be between TARGET_PAGE_BITS and
  * maximum address alignment bit.
+ *
+ * Use TARGET_PAGE_BITS_MIN so that these bits are constant
+ * when TARGET_PAGE_BITS_VARY is in effect.
  */
 /* Zero if TLB entry is valid.  */
-#define TLB_INVALID_MASK    (1 << (TARGET_PAGE_BITS - 1))
+#define TLB_INVALID_MASK    (1 << (TARGET_PAGE_BITS_MIN - 1))
 /* Set if TLB entry references a clean RAM page.  The iotlb entry will
    contain the page physical address.  */
-#define TLB_NOTDIRTY        (1 << (TARGET_PAGE_BITS - 2))
+#define TLB_NOTDIRTY        (1 << (TARGET_PAGE_BITS_MIN - 2))
 /* Set if TLB entry is an IO callback.  */
-#define TLB_MMIO            (1 << (TARGET_PAGE_BITS - 3))
+#define TLB_MMIO            (1 << (TARGET_PAGE_BITS_MIN - 3))
 /* Set if TLB entry contains a watchpoint.  */
-#define TLB_WATCHPOINT      (1 << (TARGET_PAGE_BITS - 4))
+#define TLB_WATCHPOINT      (1 << (TARGET_PAGE_BITS_MIN - 4))
 
 /* Use this mask to check interception with an alignment mask
  * in a TCG backend.