target/arm: Enable MTE

We now implement all of the components of MTE, without actually
supporting any tagged memory.  All MTE instructions will work,
trivially, so we can enable support.

Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>
Message-id: [email protected]
Signed-off-by: Peter Maydell <[email protected]>

Author: rth7680

target/arm/cpu64.c

@@ -654,6 +654,11 @@ static void aarch64_max_initfn(Object *obj)
 
         t = cpu->isar.id_aa64pfr1;
         t = FIELD_DP64(t, ID_AA64PFR1, BT, 1);
+        /*
+         * Begin with full support for MTE; will be downgraded to MTE=1
+         * during realize if the board provides no tag memory.
+         */
+        t = FIELD_DP64(t, ID_AA64PFR1, MTE, 2);
         cpu->isar.id_aa64pfr1 = t;
 
         t = cpu->isar.id_aa64mmfr1;