diff options
Diffstat (limited to 'accel/tcg/translate-all.c')
| -rw-r--r-- | accel/tcg/translate-all.c | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index d56ca13cdd..d4189c7386 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -532,9 +532,25 @@ TranslationBlock *tb_gen_code(CPUState *cpu, } /* + * Insert TB into the corresponding region tree before publishing it + * through QHT. Otherwise rewinding happened in the TB might fail to + * lookup itself using host PC. + */ + tcg_tb_insert(tb); + + /* * If the TB is not associated with a physical RAM page then it must be - * a temporary one-insn TB, and we have nothing left to do. Return early - * before attempting to link to other TBs or add to the lookup table. + * a temporary one-insn TB. + * + * Such TBs must be added to region trees in order to make sure that + * restore_state_to_opc() - which on some architectures is not limited to + * rewinding, but also affects exception handling! - is called when such a + * TB causes an exception. + * + * At the same time, temporary one-insn TBs must be executed at most once, + * because subsequent reads from, e.g., I/O memory may return different + * values. So return early before attempting to link to other TBs or add + * to the QHT. */ if (tb_page_addr0(tb) == -1) { assert_no_pages_locked(); @@ -542,13 +558,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu, } /* - * Insert TB into the corresponding region tree before publishing it - * through QHT. Otherwise rewinding happened in the TB might fail to - * lookup itself using host PC. - */ - tcg_tb_insert(tb); - - /* * No explicit memory barrier is required -- tb_link_page() makes the * TB visible in a consistent state. */ |