diff options
Diffstat (limited to 'target/arm')
| -rw-r--r-- | target/arm/op_helper.c | 7 | ||||
| -rw-r--r-- | target/arm/translate-a64.c | 8 | ||||
| -rw-r--r-- | target/arm/translate.c | 20 |
3 files changed, 29 insertions, 6 deletions
diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c index 5f3e3bdae2..d64c8670fa 100644 --- a/target/arm/op_helper.c +++ b/target/arm/op_helper.c @@ -436,6 +436,13 @@ void HELPER(yield)(CPUARMState *env) ARMCPU *cpu = arm_env_get_cpu(env); CPUState *cs = CPU(cpu); + /* When running in MTTCG we don't generate jumps to the yield and + * WFE helpers as it won't affect the scheduling of other vCPUs. + * If we wanted to more completely model WFE/SEV so we don't busy + * spin unnecessarily we would need to do something more involved. + */ + g_assert(!parallel_cpus); + /* This is a non-trappable hint instruction that generally indicates * that the guest is currently busy-looping. Yield control back to the * top level loop so that a more deserving VCPU has a chance to run. diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c index e61bbd6b3b..e15eae6d41 100644 --- a/target/arm/translate-a64.c +++ b/target/arm/translate-a64.c @@ -1328,10 +1328,14 @@ static void handle_hint(DisasContext *s, uint32_t insn, s->is_jmp = DISAS_WFI; return; case 1: /* YIELD */ - s->is_jmp = DISAS_YIELD; + if (!parallel_cpus) { + s->is_jmp = DISAS_YIELD; + } return; case 2: /* WFE */ - s->is_jmp = DISAS_WFE; + if (!parallel_cpus) { + s->is_jmp = DISAS_WFE; + } return; case 4: /* SEV */ case 5: /* SEVL */ diff --git a/target/arm/translate.c b/target/arm/translate.c index 4436d8f3a2..abc1f77ee4 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -4404,20 +4404,32 @@ static void gen_exception_return(DisasContext *s, TCGv_i32 pc) gen_rfe(s, pc, load_cpu_field(spsr)); } +/* + * For WFI we will halt the vCPU until an IRQ. For WFE and YIELD we + * only call the helper when running single threaded TCG code to ensure + * the next round-robin scheduled vCPU gets a crack. In MTTCG mode we + * just skip this instruction. Currently the SEV/SEVL instructions + * which are *one* of many ways to wake the CPU from WFE are not + * implemented so we can't sleep like WFI does. + */ static void gen_nop_hint(DisasContext *s, int val) { switch (val) { case 1: /* yield */ - gen_set_pc_im(s, s->pc); - s->is_jmp = DISAS_YIELD; + if (!parallel_cpus) { + gen_set_pc_im(s, s->pc); + s->is_jmp = DISAS_YIELD; + } break; case 3: /* wfi */ gen_set_pc_im(s, s->pc); s->is_jmp = DISAS_WFI; break; case 2: /* wfe */ - gen_set_pc_im(s, s->pc); - s->is_jmp = DISAS_WFE; + if (!parallel_cpus) { + gen_set_pc_im(s, s->pc); + s->is_jmp = DISAS_WFE; + } break; case 4: /* sev */ case 5: /* sevl */ |