s390x/tcg: store in the TB flags if AFP is enabled

We exit the TB when changing the control registers, so just like PSW
bits, this should always be consistent for a TB.

Using the PSW bit semantic makes things a lot easier compared to
manually defining the spare, shifted bits.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180927130303.12236-4-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

target/s390x/cpu.h

@@ -255,6 +255,7 @@ extern const struct VMStateDescription vmstate_s390_cpu;
 
 /* PSW defines */
 #undef PSW_MASK_PER
+#undef PSW_MASK_UNUSED_2
 #undef PSW_MASK_DAT
 #undef PSW_MASK_IO
 #undef PSW_MASK_EXT
@@ -273,6 +274,7 @@ extern const struct VMStateDescription vmstate_s390_cpu;
 #undef PSW_MASK_ESA_ADDR
 
 #define PSW_MASK_PER            0x4000000000000000ULL
+#define PSW_MASK_UNUSED_2       0x2000000000000000ULL
 #define PSW_MASK_DAT            0x0400000000000000ULL
 #define PSW_MASK_IO             0x0200000000000000ULL
 #define PSW_MASK_EXT            0x0100000000000000ULL
@@ -318,6 +320,9 @@ extern const struct VMStateDescription vmstate_s390_cpu;
 #define FLAG_MASK_PSW           (FLAG_MASK_PER | FLAG_MASK_DAT | FLAG_MASK_PSTATE \
                                 | FLAG_MASK_ASC | FLAG_MASK_64 | FLAG_MASK_32)
 
+/* we'll use some unused PSW positions to store CR flags in tb flags */
+#define FLAG_MASK_AFP           (PSW_MASK_UNUSED_2 >> FLAG_MASK_PSW_SHIFT)
+
 /* Control register 0 bits */
 #define CR0_LOWPROT             0x0000000010000000ULL
 #define CR0_SECONDARY           0x0000000004000000ULL
@@ -364,6 +369,9 @@ static inline void cpu_get_tb_cpu_state(CPUS390XState* env, target_ulong *pc,
     *pc = env->psw.addr;
     *cs_base = env->ex_value;
     *flags = (env->psw.mask >> FLAG_MASK_PSW_SHIFT) & FLAG_MASK_PSW;
+    if (env->cregs[0] & CR0_AFP) {
+        *flags |= FLAG_MASK_AFP;
+    }
 }
 
 /* PER bits from control register 9 */