By definition a single instruction is capable of being an IO instruction. This avoids a problem of triggering a cpu_io_recompile on a non-recorded translation which then fails because it expects tcg_tb_lookup() to succeed unconditionally. The normal use case requires a TB to be able to resolve machine state.
The other users of tcg_tb_lookup() are able to tolerate a missing TB if the machine state has been resolved by other means - which in the single-shot case is always true because machine state is synced at the start of a block. Reported-by: Peter Maydell <peter.mayd...@linaro.org> Signed-off-by: Alex Bennée <alex.ben...@linaro.org> --- accel/tcg/translate-all.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index ba6ab09790..b12d0898d0 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -1863,7 +1863,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, if (phys_pc == -1) { /* Generate a one-shot TB with 1 insn in it */ - cflags = (cflags & ~CF_COUNT_MASK) | 1; + cflags = (cflags & ~CF_COUNT_MASK) | CF_LAST_IO | 1; } max_insns = cflags & CF_COUNT_MASK; -- 2.20.1