diff options
Diffstat (limited to 'cpus.c')
| -rw-r--r-- | cpus.c | 72 |
1 files changed, 47 insertions, 25 deletions
@@ -129,21 +129,27 @@ typedef struct TimersState { int64_t cpu_ticks_prev; int64_t cpu_ticks_offset; - /* cpu_clock_offset can be read out of BQL, so protect it with - * this lock. + /* Protect fields that can be respectively read outside the + * BQL, and written from multiple threads. */ QemuSeqLock vm_clock_seqlock; - int64_t cpu_clock_offset; - int32_t cpu_ticks_enabled; + QemuSpin vm_clock_lock; + + int16_t cpu_ticks_enabled; /* Conversion factor from emulated instructions to virtual clock ticks. */ - int icount_time_shift; + int16_t icount_time_shift; + /* Compensate for varying guest execution speed. */ int64_t qemu_icount_bias; + + int64_t vm_clock_warp_start; + int64_t cpu_clock_offset; + /* Only written by TCG thread */ int64_t qemu_icount; + /* for adjusting icount */ - int64_t vm_clock_warp_start; QEMUTimer *icount_rt_timer; QEMUTimer *icount_vm_timer; QEMUTimer *icount_warp_timer; @@ -244,11 +250,15 @@ void cpu_update_icount(CPUState *cpu) int64_t executed = cpu_get_icount_executed(cpu); cpu->icount_budget -= executed; -#ifdef CONFIG_ATOMIC64 +#ifndef CONFIG_ATOMIC64 + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); +#endif atomic_set__nocheck(&timers_state.qemu_icount, timers_state.qemu_icount + executed); -#else /* FIXME: we need 64bit atomics to do this safely */ - timers_state.qemu_icount += executed; +#ifndef CONFIG_ATOMIC64 + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); #endif } @@ -369,14 +379,15 @@ int64_t cpu_get_clock(void) */ void cpu_enable_ticks(void) { - /* Here, the really thing protected by seqlock is cpu_clock_offset. */ - seqlock_write_begin(&timers_state.vm_clock_seqlock); + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); if (!timers_state.cpu_ticks_enabled) { timers_state.cpu_ticks_offset -= cpu_get_host_ticks(); timers_state.cpu_clock_offset -= get_clock(); timers_state.cpu_ticks_enabled = 1; } - seqlock_write_end(&timers_state.vm_clock_seqlock); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); } /* disable cpu_get_ticks() : the clock is stopped. You must not call @@ -385,14 +396,15 @@ void cpu_enable_ticks(void) */ void cpu_disable_ticks(void) { - /* Here, the really thing protected by seqlock is cpu_clock_offset. */ - seqlock_write_begin(&timers_state.vm_clock_seqlock); + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); if (timers_state.cpu_ticks_enabled) { timers_state.cpu_ticks_offset += cpu_get_host_ticks(); timers_state.cpu_clock_offset = cpu_get_clock_locked(); timers_state.cpu_ticks_enabled = 0; } - seqlock_write_end(&timers_state.vm_clock_seqlock); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); } /* Correlation between real and virtual time is always going to be @@ -415,7 +427,8 @@ static void icount_adjust(void) return; } - seqlock_write_begin(&timers_state.vm_clock_seqlock); + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); cur_time = cpu_get_clock_locked(); cur_icount = cpu_get_icount_locked(); @@ -439,7 +452,8 @@ static void icount_adjust(void) atomic_set__nocheck(&timers_state.qemu_icount_bias, cur_icount - (timers_state.qemu_icount << timers_state.icount_time_shift)); - seqlock_write_end(&timers_state.vm_clock_seqlock); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); } static void icount_adjust_rt(void *opaque) @@ -480,7 +494,8 @@ static void icount_warp_rt(void) return; } - seqlock_write_begin(&timers_state.vm_clock_seqlock); + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); if (runstate_is_running()) { int64_t clock = REPLAY_CLOCK(REPLAY_CLOCK_VIRTUAL_RT, cpu_get_clock_locked()); @@ -500,7 +515,8 @@ static void icount_warp_rt(void) timers_state.qemu_icount_bias + warp_delta); } timers_state.vm_clock_warp_start = -1; - seqlock_write_end(&timers_state.vm_clock_seqlock); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); if (qemu_clock_expired(QEMU_CLOCK_VIRTUAL)) { qemu_clock_notify(QEMU_CLOCK_VIRTUAL); @@ -525,10 +541,12 @@ void qtest_clock_warp(int64_t dest) int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL); int64_t warp = qemu_soonest_timeout(dest - clock, deadline); - seqlock_write_begin(&timers_state.vm_clock_seqlock); + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); atomic_set__nocheck(&timers_state.qemu_icount_bias, timers_state.qemu_icount_bias + warp); - seqlock_write_end(&timers_state.vm_clock_seqlock); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL); timerlist_run_timers(aio_context->tlg.tl[QEMU_CLOCK_VIRTUAL]); @@ -595,10 +613,12 @@ void qemu_start_warp_timer(void) * It is useful when we want a deterministic execution time, * isolated from host latencies. */ - seqlock_write_begin(&timers_state.vm_clock_seqlock); + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); atomic_set__nocheck(&timers_state.qemu_icount_bias, timers_state.qemu_icount_bias + deadline); - seqlock_write_end(&timers_state.vm_clock_seqlock); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); qemu_clock_notify(QEMU_CLOCK_VIRTUAL); } else { /* @@ -609,12 +629,14 @@ void qemu_start_warp_timer(void) * you will not be sending network packets continuously instead of * every 100ms. */ - seqlock_write_begin(&timers_state.vm_clock_seqlock); + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); if (timers_state.vm_clock_warp_start == -1 || timers_state.vm_clock_warp_start > clock) { timers_state.vm_clock_warp_start = clock; } - seqlock_write_end(&timers_state.vm_clock_seqlock); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); timer_mod_anticipate(timers_state.icount_warp_timer, clock + deadline); } |