> From: Paolo Bonzini [mailto:pbonz...@redhat.com] > On 05/12/2014 11:55, Pavel Dovgaluk wrote: > >> > > >> > And why is can_do_io zero? :) Is the fix to move the place where > >> > can_do_io becomes nonzero? > > can_do_io is set by gen_io_start function. > > As I understand, it is used to protect determinism in icount mode, > > because it allows non-deterministic (port io, raising interrupt) > > operations only at the end of the translation blocks. > > When someone tries to use MMIO in the middle of TB, that TB is > > recompiled to place this instruction at the end of the block. > > > > Do you mean that we can set can_do_io before execution of the block > > and reset it at the beginning of the execution? > > Yes, we could try setting it after execution of the block and clearing > it afterwards. Peter knows that part of icount better though (I know > mostly the timer/warping parts).
Ok, how about these changes? diff --git a/cpu-exec.c b/cpu-exec.c index f52f292..88675ca 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -168,7 +168,9 @@ static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr) } #endif /* DEBUG_DISAS */ + cpu->can_do_io = 0; next_tb = tcg_qemu_tb_exec(env, tb_ptr); + cpu->can_do_io = 1; trace_exec_tb_exit((void *) (next_tb & ~TB_EXIT_MASK), next_tb & TB_EXIT_MASK); @@ -548,6 +550,7 @@ int cpu_exec(CPUArchState *env) cpu = current_cpu; env = cpu->env_ptr; cc = CPU_GET_CLASS(cpu); + cpu->can_do_io = 1; #ifdef TARGET_I386 x86_cpu = X86_CPU(cpu); #endif diff --git a/cpus.c b/cpus.c index 0c33458..7a45a51 100644 --- a/cpus.c +++ b/cpus.c @@ -934,6 +934,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) qemu_mutex_lock(&qemu_global_mutex); qemu_thread_get_self(cpu->thread); cpu->thread_id = qemu_get_thread_id(); + cpu->can_do_io = 1; current_cpu = cpu; r = kvm_init_vcpu(cpu); @@ -974,6 +975,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg) qemu_mutex_lock_iothread(); qemu_thread_get_self(cpu->thread); cpu->thread_id = qemu_get_thread_id(); + cpu->can_do_io = 1; sigemptyset(&waitset); sigaddset(&waitset, SIG_IPI); @@ -1016,6 +1018,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) CPU_FOREACH(cpu) { cpu->thread_id = qemu_get_thread_id(); cpu->created = true; + cpu->can_do_io = 1; } qemu_cond_signal(&qemu_cpu_cond);