accel/tcg: Use correct test when looking in victim TLB for code

In get_page_addr_code(), we were incorrectly looking in the victim
TLB for an entry which matched the target address for reads, not
for code accesses. This meant that we could hit on a victim TLB
entry that indicated that the address was readable but not
executable, and incorrectly bypass the call to tlb_fill() which
should generate the guest MMU exception. Fix this bug.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Message-id: 20180713141636.18665-2-peter.maydell@linaro.org

accel/tcg/cputlb.c

@@ -967,7 +967,7 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env, target_ulong addr)
     index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
     mmu_idx = cpu_mmu_index(env, true);
     if (unlikely(!tlb_hit(env->tlb_table[mmu_idx][index].addr_code, addr))) {
-        if (!VICTIM_TLB_HIT(addr_read, addr)) {
+        if (!VICTIM_TLB_HIT(addr_code, addr)) {
             tlb_fill(ENV_GET_CPU(env), addr, 0, MMU_INST_FETCH, mmu_idx, 0);
         }
     }