> From: Paolo Bonzini [mailto:pbonz...@redhat.com] > On 24/07/19 10:44, Pavel Dovgalyuk wrote: > > From: Pavel Dovgalyuk <pavel.dovga...@ispras.ru> > > > > Most of IO instructions can be executed only at the end of the block in > > icount mode. Therefore translator can set cpu_can_io flag when translating > > the last instruction. > > But when the blocks are chained, then this flag is not reset and may > > remain set at the beginning of the next block. > > This patch resets the flag before "chaining" the translation blocks. > > > > Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru> > > --- > > accel/tcg/tcg-runtime.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/accel/tcg/tcg-runtime.c b/accel/tcg/tcg-runtime.c > > index 8a1e408e31..fe6b83d0fc 100644 > > --- a/accel/tcg/tcg-runtime.c > > +++ b/accel/tcg/tcg-runtime.c > > @@ -151,6 +151,8 @@ void *HELPER(lookup_tb_ptr)(CPUArchState *env) > > target_ulong cs_base, pc; > > uint32_t flags; > > > > + /* We are going to jump to the next block. can_do_io should be reset */ > > + cpu->can_do_io = !use_icount; > > tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, curr_cflags()); > > if (tb == NULL) { > > return tcg_ctx->code_gen_epilogue; > > > > This only fixes indirect jumps though. > > I think you do not need this patch if you remove the assignment in > cpu_tb_exec, and compile a "move 0 to cpu->can_do_io" in gen_tb_start > instead.
"move 0 to cpu->can_do_io" only for icount mode? And we'll also need to set can_do_io to 1 somewhere, because it is checked in non-icount mode too. Pavel Dovgalyuk
