From: Philippe Mathieu-Daudé Date: Thu, 14 Sep 2023 18:57:16 +0000 (+0200) Subject: accel/tcg: Make icount.o a target agnostic unit X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=467bf3fc09d08937061c86eefef185341e4c2cf8;p=qemu.git accel/tcg: Make icount.o a target agnostic unit Remove the unused "exec/exec-all.h" header. There is no more target specific code in it: make it target agnostic (rename using the '-common' suffix). Since it is TCG specific, move it to accel/tcg, updating MAINTAINERS. Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Anton Johansson Message-Id: <20230914185718.76241-11-philmd@linaro.org> Signed-off-by: Richard Henderson --- diff --git a/MAINTAINERS b/MAINTAINERS index cb2dbd967e..78199101aa 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2906,7 +2906,6 @@ F: softmmu/main.c F: softmmu/cpus.c F: softmmu/cpu-throttle.c F: softmmu/cpu-timers.c -F: softmmu/icount.c F: softmmu/runstate* F: qapi/run-state.json diff --git a/accel/tcg/icount-common.c b/accel/tcg/icount-common.c new file mode 100644 index 0000000000..0bf5bb5e21 --- /dev/null +++ b/accel/tcg/icount-common.c @@ -0,0 +1,502 @@ +/* + * QEMU System Emulator + * + * Copyright (c) 2003-2008 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu/cutils.h" +#include "migration/vmstate.h" +#include "qapi/error.h" +#include "qemu/error-report.h" +#include "sysemu/cpus.h" +#include "sysemu/qtest.h" +#include "qemu/main-loop.h" +#include "qemu/option.h" +#include "qemu/seqlock.h" +#include "sysemu/replay.h" +#include "sysemu/runstate.h" +#include "hw/core/cpu.h" +#include "sysemu/cpu-timers.h" +#include "sysemu/cpu-throttle.h" +#include "softmmu/timers-state.h" + +/* + * ICOUNT: Instruction Counter + * + * this module is split off from cpu-timers because the icount part + * is TCG-specific, and does not need to be built for other accels. + */ +static bool icount_sleep = true; +/* Arbitrarily pick 1MIPS as the minimum allowable speed. */ +#define MAX_ICOUNT_SHIFT 10 + +/* + * 0 = Do not count executed instructions. + * 1 = Fixed conversion of insn to ns via "shift" option + * 2 = Runtime adaptive algorithm to compute shift + */ +int use_icount; + +static void icount_enable_precise(void) +{ + use_icount = 1; +} + +static void icount_enable_adaptive(void) +{ + use_icount = 2; +} + +/* + * The current number of executed instructions is based on what we + * originally budgeted minus the current state of the decrementing + * icount counters in extra/u16.low. + */ +static int64_t icount_get_executed(CPUState *cpu) +{ + return (cpu->icount_budget - + (cpu->neg.icount_decr.u16.low + cpu->icount_extra)); +} + +/* + * Update the global shared timer_state.qemu_icount to take into + * account executed instructions. This is done by the TCG vCPU + * thread so the main-loop can see time has moved forward. + */ +static void icount_update_locked(CPUState *cpu) +{ + int64_t executed = icount_get_executed(cpu); + cpu->icount_budget -= executed; + + qatomic_set_i64(&timers_state.qemu_icount, + timers_state.qemu_icount + executed); +} + +/* + * Update the global shared timer_state.qemu_icount to take into + * account executed instructions. This is done by the TCG vCPU + * thread so the main-loop can see time has moved forward. + */ +void icount_update(CPUState *cpu) +{ + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); + icount_update_locked(cpu); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); +} + +static int64_t icount_get_raw_locked(void) +{ + CPUState *cpu = current_cpu; + + if (cpu && cpu->running) { + if (!cpu->neg.can_do_io) { + error_report("Bad icount read"); + exit(1); + } + /* Take into account what has run */ + icount_update_locked(cpu); + } + /* The read is protected by the seqlock, but needs atomic64 to avoid UB */ + return qatomic_read_i64(&timers_state.qemu_icount); +} + +static int64_t icount_get_locked(void) +{ + int64_t icount = icount_get_raw_locked(); + return qatomic_read_i64(&timers_state.qemu_icount_bias) + + icount_to_ns(icount); +} + +int64_t icount_get_raw(void) +{ + int64_t icount; + unsigned start; + + do { + start = seqlock_read_begin(&timers_state.vm_clock_seqlock); + icount = icount_get_raw_locked(); + } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start)); + + return icount; +} + +/* Return the virtual CPU time, based on the instruction counter. */ +int64_t icount_get(void) +{ + int64_t icount; + unsigned start; + + do { + start = seqlock_read_begin(&timers_state.vm_clock_seqlock); + icount = icount_get_locked(); + } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start)); + + return icount; +} + +int64_t icount_to_ns(int64_t icount) +{ + return icount << qatomic_read(&timers_state.icount_time_shift); +} + +/* + * Correlation between real and virtual time is always going to be + * fairly approximate, so ignore small variation. + * When the guest is idle real and virtual time will be aligned in + * the IO wait loop. + */ +#define ICOUNT_WOBBLE (NANOSECONDS_PER_SECOND / 10) + +static void icount_adjust(void) +{ + int64_t cur_time; + int64_t cur_icount; + int64_t delta; + + /* If the VM is not running, then do nothing. */ + if (!runstate_is_running()) { + return; + } + + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); + cur_time = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT, + cpu_get_clock_locked()); + cur_icount = icount_get_locked(); + + delta = cur_icount - cur_time; + /* FIXME: This is a very crude algorithm, somewhat prone to oscillation. */ + if (delta > 0 + && timers_state.last_delta + ICOUNT_WOBBLE < delta * 2 + && timers_state.icount_time_shift > 0) { + /* The guest is getting too far ahead. Slow time down. */ + qatomic_set(&timers_state.icount_time_shift, + timers_state.icount_time_shift - 1); + } + if (delta < 0 + && timers_state.last_delta - ICOUNT_WOBBLE > delta * 2 + && timers_state.icount_time_shift < MAX_ICOUNT_SHIFT) { + /* The guest is getting too far behind. Speed time up. */ + qatomic_set(&timers_state.icount_time_shift, + timers_state.icount_time_shift + 1); + } + timers_state.last_delta = delta; + qatomic_set_i64(&timers_state.qemu_icount_bias, + cur_icount - (timers_state.qemu_icount + << timers_state.icount_time_shift)); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); +} + +static void icount_adjust_rt(void *opaque) +{ + timer_mod(timers_state.icount_rt_timer, + qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000); + icount_adjust(); +} + +static void icount_adjust_vm(void *opaque) +{ + timer_mod(timers_state.icount_vm_timer, + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + + NANOSECONDS_PER_SECOND / 10); + icount_adjust(); +} + +int64_t icount_round(int64_t count) +{ + int shift = qatomic_read(&timers_state.icount_time_shift); + return (count + (1 << shift) - 1) >> shift; +} + +static void icount_warp_rt(void) +{ + unsigned seq; + int64_t warp_start; + + /* + * The icount_warp_timer is rescheduled soon after vm_clock_warp_start + * changes from -1 to another value, so the race here is okay. + */ + do { + seq = seqlock_read_begin(&timers_state.vm_clock_seqlock); + warp_start = timers_state.vm_clock_warp_start; + } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, seq)); + + if (warp_start == -1) { + return; + } + + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); + if (runstate_is_running()) { + int64_t clock = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT, + cpu_get_clock_locked()); + int64_t warp_delta; + + warp_delta = clock - timers_state.vm_clock_warp_start; + if (icount_enabled() == 2) { + /* + * In adaptive mode, do not let QEMU_CLOCK_VIRTUAL run too far + * ahead of real time (it might already be ahead so careful not + * to go backwards). + */ + int64_t cur_icount = icount_get_locked(); + int64_t delta = clock - cur_icount; + + if (delta < 0) { + delta = 0; + } + warp_delta = MIN(warp_delta, delta); + } + qatomic_set_i64(&timers_state.qemu_icount_bias, + timers_state.qemu_icount_bias + warp_delta); + } + timers_state.vm_clock_warp_start = -1; + 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); + } +} + +static void icount_timer_cb(void *opaque) +{ + /* + * No need for a checkpoint because the timer already synchronizes + * with CHECKPOINT_CLOCK_VIRTUAL_RT. + */ + icount_warp_rt(); +} + +void icount_start_warp_timer(void) +{ + int64_t clock; + int64_t deadline; + + assert(icount_enabled()); + + /* + * Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers + * do not fire, so computing the deadline does not make sense. + */ + if (!runstate_is_running()) { + return; + } + + if (replay_mode != REPLAY_MODE_PLAY) { + if (!all_cpu_threads_idle()) { + return; + } + + if (qtest_enabled()) { + /* When testing, qtest commands advance icount. */ + return; + } + + replay_checkpoint(CHECKPOINT_CLOCK_WARP_START); + } else { + /* warp clock deterministically in record/replay mode */ + if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_START)) { + /* + * vCPU is sleeping and warp can't be started. + * It is probably a race condition: notification sent + * to vCPU was processed in advance and vCPU went to sleep. + * Therefore we have to wake it up for doing something. + */ + if (replay_has_event()) { + qemu_clock_notify(QEMU_CLOCK_VIRTUAL); + } + return; + } + } + + /* We want to use the earliest deadline from ALL vm_clocks */ + clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT); + deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL, + ~QEMU_TIMER_ATTR_EXTERNAL); + if (deadline < 0) { + static bool notified; + if (!icount_sleep && !notified) { + warn_report("icount sleep disabled and no active timers"); + notified = true; + } + return; + } + + if (deadline > 0) { + /* + * Ensure QEMU_CLOCK_VIRTUAL proceeds even when the virtual CPU goes to + * sleep. Otherwise, the CPU might be waiting for a future timer + * interrupt to wake it up, but the interrupt never comes because + * the vCPU isn't running any insns and thus doesn't advance the + * QEMU_CLOCK_VIRTUAL. + */ + if (!icount_sleep) { + /* + * We never let VCPUs sleep in no sleep icount mode. + * If there is a pending QEMU_CLOCK_VIRTUAL timer we just advance + * to the next QEMU_CLOCK_VIRTUAL event and notify it. + * It is useful when we want a deterministic execution time, + * isolated from host latencies. + */ + seqlock_write_lock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); + qatomic_set_i64(&timers_state.qemu_icount_bias, + timers_state.qemu_icount_bias + deadline); + seqlock_write_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); + qemu_clock_notify(QEMU_CLOCK_VIRTUAL); + } else { + /* + * We do stop VCPUs and only advance QEMU_CLOCK_VIRTUAL after some + * "real" time, (related to the time left until the next event) has + * passed. The QEMU_CLOCK_VIRTUAL_RT clock will do this. + * This avoids that the warps are visible externally; for example, + * you will not be sending network packets continuously instead of + * every 100ms. + */ + 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_unlock(&timers_state.vm_clock_seqlock, + &timers_state.vm_clock_lock); + timer_mod_anticipate(timers_state.icount_warp_timer, + clock + deadline); + } + } else if (deadline == 0) { + qemu_clock_notify(QEMU_CLOCK_VIRTUAL); + } +} + +void icount_account_warp_timer(void) +{ + if (!icount_sleep) { + return; + } + + /* + * Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers + * do not fire, so computing the deadline does not make sense. + */ + if (!runstate_is_running()) { + return; + } + + replay_async_events(); + + /* warp clock deterministically in record/replay mode */ + if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_ACCOUNT)) { + return; + } + + timer_del(timers_state.icount_warp_timer); + icount_warp_rt(); +} + +void icount_configure(QemuOpts *opts, Error **errp) +{ + const char *option = qemu_opt_get(opts, "shift"); + bool sleep = qemu_opt_get_bool(opts, "sleep", true); + bool align = qemu_opt_get_bool(opts, "align", false); + long time_shift = -1; + + if (!option) { + if (qemu_opt_get(opts, "align") != NULL) { + error_setg(errp, "Please specify shift option when using align"); + } + return; + } + + if (align && !sleep) { + error_setg(errp, "align=on and sleep=off are incompatible"); + return; + } + + if (strcmp(option, "auto") != 0) { + if (qemu_strtol(option, NULL, 0, &time_shift) < 0 + || time_shift < 0 || time_shift > MAX_ICOUNT_SHIFT) { + error_setg(errp, "icount: Invalid shift value"); + return; + } + } else if (icount_align_option) { + error_setg(errp, "shift=auto and align=on are incompatible"); + return; + } else if (!icount_sleep) { + error_setg(errp, "shift=auto and sleep=off are incompatible"); + return; + } + + icount_sleep = sleep; + if (icount_sleep) { + timers_state.icount_warp_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT, + icount_timer_cb, NULL); + } + + icount_align_option = align; + + if (time_shift >= 0) { + timers_state.icount_time_shift = time_shift; + icount_enable_precise(); + return; + } + + icount_enable_adaptive(); + + /* + * 125MIPS seems a reasonable initial guess at the guest speed. + * It will be corrected fairly quickly anyway. + */ + timers_state.icount_time_shift = 3; + + /* + * Have both realtime and virtual time triggers for speed adjustment. + * The realtime trigger catches emulated time passing too slowly, + * the virtual time trigger catches emulated time passing too fast. + * Realtime triggers occur even when idle, so use them less frequently + * than VM triggers. + */ + timers_state.vm_clock_warp_start = -1; + timers_state.icount_rt_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL_RT, + icount_adjust_rt, NULL); + timer_mod(timers_state.icount_rt_timer, + qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000); + timers_state.icount_vm_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, + icount_adjust_vm, NULL); + timer_mod(timers_state.icount_vm_timer, + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + + NANOSECONDS_PER_SECOND / 10); +} + +void icount_notify_exit(void) +{ + if (icount_enabled() && current_cpu) { + qemu_cpu_kick(current_cpu); + qemu_clock_notify(QEMU_CLOCK_VIRTUAL); + } +} diff --git a/accel/tcg/meson.build b/accel/tcg/meson.build index 0fb03bd7d3..4633a34d28 100644 --- a/accel/tcg/meson.build +++ b/accel/tcg/meson.build @@ -23,6 +23,7 @@ specific_ss.add(when: ['CONFIG_SYSTEM_ONLY', 'CONFIG_TCG'], if_true: files( )) system_ss.add(when: ['CONFIG_TCG'], if_true: files( + 'icount-common.c', 'monitor.c', )) diff --git a/softmmu/icount.c b/softmmu/icount.c deleted file mode 100644 index 4527bfbd6e..0000000000 --- a/softmmu/icount.c +++ /dev/null @@ -1,503 +0,0 @@ -/* - * QEMU System Emulator - * - * Copyright (c) 2003-2008 Fabrice Bellard - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN - * THE SOFTWARE. - */ - -#include "qemu/osdep.h" -#include "qemu/cutils.h" -#include "migration/vmstate.h" -#include "qapi/error.h" -#include "qemu/error-report.h" -#include "exec/exec-all.h" -#include "sysemu/cpus.h" -#include "sysemu/qtest.h" -#include "qemu/main-loop.h" -#include "qemu/option.h" -#include "qemu/seqlock.h" -#include "sysemu/replay.h" -#include "sysemu/runstate.h" -#include "hw/core/cpu.h" -#include "sysemu/cpu-timers.h" -#include "sysemu/cpu-throttle.h" -#include "timers-state.h" - -/* - * ICOUNT: Instruction Counter - * - * this module is split off from cpu-timers because the icount part - * is TCG-specific, and does not need to be built for other accels. - */ -static bool icount_sleep = true; -/* Arbitrarily pick 1MIPS as the minimum allowable speed. */ -#define MAX_ICOUNT_SHIFT 10 - -/* - * 0 = Do not count executed instructions. - * 1 = Fixed conversion of insn to ns via "shift" option - * 2 = Runtime adaptive algorithm to compute shift - */ -int use_icount; - -static void icount_enable_precise(void) -{ - use_icount = 1; -} - -static void icount_enable_adaptive(void) -{ - use_icount = 2; -} - -/* - * The current number of executed instructions is based on what we - * originally budgeted minus the current state of the decrementing - * icount counters in extra/u16.low. - */ -static int64_t icount_get_executed(CPUState *cpu) -{ - return (cpu->icount_budget - - (cpu->neg.icount_decr.u16.low + cpu->icount_extra)); -} - -/* - * Update the global shared timer_state.qemu_icount to take into - * account executed instructions. This is done by the TCG vCPU - * thread so the main-loop can see time has moved forward. - */ -static void icount_update_locked(CPUState *cpu) -{ - int64_t executed = icount_get_executed(cpu); - cpu->icount_budget -= executed; - - qatomic_set_i64(&timers_state.qemu_icount, - timers_state.qemu_icount + executed); -} - -/* - * Update the global shared timer_state.qemu_icount to take into - * account executed instructions. This is done by the TCG vCPU - * thread so the main-loop can see time has moved forward. - */ -void icount_update(CPUState *cpu) -{ - seqlock_write_lock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); - icount_update_locked(cpu); - seqlock_write_unlock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); -} - -static int64_t icount_get_raw_locked(void) -{ - CPUState *cpu = current_cpu; - - if (cpu && cpu->running) { - if (!cpu->neg.can_do_io) { - error_report("Bad icount read"); - exit(1); - } - /* Take into account what has run */ - icount_update_locked(cpu); - } - /* The read is protected by the seqlock, but needs atomic64 to avoid UB */ - return qatomic_read_i64(&timers_state.qemu_icount); -} - -static int64_t icount_get_locked(void) -{ - int64_t icount = icount_get_raw_locked(); - return qatomic_read_i64(&timers_state.qemu_icount_bias) + - icount_to_ns(icount); -} - -int64_t icount_get_raw(void) -{ - int64_t icount; - unsigned start; - - do { - start = seqlock_read_begin(&timers_state.vm_clock_seqlock); - icount = icount_get_raw_locked(); - } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start)); - - return icount; -} - -/* Return the virtual CPU time, based on the instruction counter. */ -int64_t icount_get(void) -{ - int64_t icount; - unsigned start; - - do { - start = seqlock_read_begin(&timers_state.vm_clock_seqlock); - icount = icount_get_locked(); - } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start)); - - return icount; -} - -int64_t icount_to_ns(int64_t icount) -{ - return icount << qatomic_read(&timers_state.icount_time_shift); -} - -/* - * Correlation between real and virtual time is always going to be - * fairly approximate, so ignore small variation. - * When the guest is idle real and virtual time will be aligned in - * the IO wait loop. - */ -#define ICOUNT_WOBBLE (NANOSECONDS_PER_SECOND / 10) - -static void icount_adjust(void) -{ - int64_t cur_time; - int64_t cur_icount; - int64_t delta; - - /* If the VM is not running, then do nothing. */ - if (!runstate_is_running()) { - return; - } - - seqlock_write_lock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); - cur_time = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT, - cpu_get_clock_locked()); - cur_icount = icount_get_locked(); - - delta = cur_icount - cur_time; - /* FIXME: This is a very crude algorithm, somewhat prone to oscillation. */ - if (delta > 0 - && timers_state.last_delta + ICOUNT_WOBBLE < delta * 2 - && timers_state.icount_time_shift > 0) { - /* The guest is getting too far ahead. Slow time down. */ - qatomic_set(&timers_state.icount_time_shift, - timers_state.icount_time_shift - 1); - } - if (delta < 0 - && timers_state.last_delta - ICOUNT_WOBBLE > delta * 2 - && timers_state.icount_time_shift < MAX_ICOUNT_SHIFT) { - /* The guest is getting too far behind. Speed time up. */ - qatomic_set(&timers_state.icount_time_shift, - timers_state.icount_time_shift + 1); - } - timers_state.last_delta = delta; - qatomic_set_i64(&timers_state.qemu_icount_bias, - cur_icount - (timers_state.qemu_icount - << timers_state.icount_time_shift)); - seqlock_write_unlock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); -} - -static void icount_adjust_rt(void *opaque) -{ - timer_mod(timers_state.icount_rt_timer, - qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000); - icount_adjust(); -} - -static void icount_adjust_vm(void *opaque) -{ - timer_mod(timers_state.icount_vm_timer, - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + - NANOSECONDS_PER_SECOND / 10); - icount_adjust(); -} - -int64_t icount_round(int64_t count) -{ - int shift = qatomic_read(&timers_state.icount_time_shift); - return (count + (1 << shift) - 1) >> shift; -} - -static void icount_warp_rt(void) -{ - unsigned seq; - int64_t warp_start; - - /* - * The icount_warp_timer is rescheduled soon after vm_clock_warp_start - * changes from -1 to another value, so the race here is okay. - */ - do { - seq = seqlock_read_begin(&timers_state.vm_clock_seqlock); - warp_start = timers_state.vm_clock_warp_start; - } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, seq)); - - if (warp_start == -1) { - return; - } - - seqlock_write_lock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); - if (runstate_is_running()) { - int64_t clock = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT, - cpu_get_clock_locked()); - int64_t warp_delta; - - warp_delta = clock - timers_state.vm_clock_warp_start; - if (icount_enabled() == 2) { - /* - * In adaptive mode, do not let QEMU_CLOCK_VIRTUAL run too far - * ahead of real time (it might already be ahead so careful not - * to go backwards). - */ - int64_t cur_icount = icount_get_locked(); - int64_t delta = clock - cur_icount; - - if (delta < 0) { - delta = 0; - } - warp_delta = MIN(warp_delta, delta); - } - qatomic_set_i64(&timers_state.qemu_icount_bias, - timers_state.qemu_icount_bias + warp_delta); - } - timers_state.vm_clock_warp_start = -1; - 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); - } -} - -static void icount_timer_cb(void *opaque) -{ - /* - * No need for a checkpoint because the timer already synchronizes - * with CHECKPOINT_CLOCK_VIRTUAL_RT. - */ - icount_warp_rt(); -} - -void icount_start_warp_timer(void) -{ - int64_t clock; - int64_t deadline; - - assert(icount_enabled()); - - /* - * Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers - * do not fire, so computing the deadline does not make sense. - */ - if (!runstate_is_running()) { - return; - } - - if (replay_mode != REPLAY_MODE_PLAY) { - if (!all_cpu_threads_idle()) { - return; - } - - if (qtest_enabled()) { - /* When testing, qtest commands advance icount. */ - return; - } - - replay_checkpoint(CHECKPOINT_CLOCK_WARP_START); - } else { - /* warp clock deterministically in record/replay mode */ - if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_START)) { - /* - * vCPU is sleeping and warp can't be started. - * It is probably a race condition: notification sent - * to vCPU was processed in advance and vCPU went to sleep. - * Therefore we have to wake it up for doing something. - */ - if (replay_has_event()) { - qemu_clock_notify(QEMU_CLOCK_VIRTUAL); - } - return; - } - } - - /* We want to use the earliest deadline from ALL vm_clocks */ - clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT); - deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL, - ~QEMU_TIMER_ATTR_EXTERNAL); - if (deadline < 0) { - static bool notified; - if (!icount_sleep && !notified) { - warn_report("icount sleep disabled and no active timers"); - notified = true; - } - return; - } - - if (deadline > 0) { - /* - * Ensure QEMU_CLOCK_VIRTUAL proceeds even when the virtual CPU goes to - * sleep. Otherwise, the CPU might be waiting for a future timer - * interrupt to wake it up, but the interrupt never comes because - * the vCPU isn't running any insns and thus doesn't advance the - * QEMU_CLOCK_VIRTUAL. - */ - if (!icount_sleep) { - /* - * We never let VCPUs sleep in no sleep icount mode. - * If there is a pending QEMU_CLOCK_VIRTUAL timer we just advance - * to the next QEMU_CLOCK_VIRTUAL event and notify it. - * It is useful when we want a deterministic execution time, - * isolated from host latencies. - */ - seqlock_write_lock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); - qatomic_set_i64(&timers_state.qemu_icount_bias, - timers_state.qemu_icount_bias + deadline); - seqlock_write_unlock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); - qemu_clock_notify(QEMU_CLOCK_VIRTUAL); - } else { - /* - * We do stop VCPUs and only advance QEMU_CLOCK_VIRTUAL after some - * "real" time, (related to the time left until the next event) has - * passed. The QEMU_CLOCK_VIRTUAL_RT clock will do this. - * This avoids that the warps are visible externally; for example, - * you will not be sending network packets continuously instead of - * every 100ms. - */ - 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_unlock(&timers_state.vm_clock_seqlock, - &timers_state.vm_clock_lock); - timer_mod_anticipate(timers_state.icount_warp_timer, - clock + deadline); - } - } else if (deadline == 0) { - qemu_clock_notify(QEMU_CLOCK_VIRTUAL); - } -} - -void icount_account_warp_timer(void) -{ - if (!icount_sleep) { - return; - } - - /* - * Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers - * do not fire, so computing the deadline does not make sense. - */ - if (!runstate_is_running()) { - return; - } - - replay_async_events(); - - /* warp clock deterministically in record/replay mode */ - if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_ACCOUNT)) { - return; - } - - timer_del(timers_state.icount_warp_timer); - icount_warp_rt(); -} - -void icount_configure(QemuOpts *opts, Error **errp) -{ - const char *option = qemu_opt_get(opts, "shift"); - bool sleep = qemu_opt_get_bool(opts, "sleep", true); - bool align = qemu_opt_get_bool(opts, "align", false); - long time_shift = -1; - - if (!option) { - if (qemu_opt_get(opts, "align") != NULL) { - error_setg(errp, "Please specify shift option when using align"); - } - return; - } - - if (align && !sleep) { - error_setg(errp, "align=on and sleep=off are incompatible"); - return; - } - - if (strcmp(option, "auto") != 0) { - if (qemu_strtol(option, NULL, 0, &time_shift) < 0 - || time_shift < 0 || time_shift > MAX_ICOUNT_SHIFT) { - error_setg(errp, "icount: Invalid shift value"); - return; - } - } else if (icount_align_option) { - error_setg(errp, "shift=auto and align=on are incompatible"); - return; - } else if (!icount_sleep) { - error_setg(errp, "shift=auto and sleep=off are incompatible"); - return; - } - - icount_sleep = sleep; - if (icount_sleep) { - timers_state.icount_warp_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT, - icount_timer_cb, NULL); - } - - icount_align_option = align; - - if (time_shift >= 0) { - timers_state.icount_time_shift = time_shift; - icount_enable_precise(); - return; - } - - icount_enable_adaptive(); - - /* - * 125MIPS seems a reasonable initial guess at the guest speed. - * It will be corrected fairly quickly anyway. - */ - timers_state.icount_time_shift = 3; - - /* - * Have both realtime and virtual time triggers for speed adjustment. - * The realtime trigger catches emulated time passing too slowly, - * the virtual time trigger catches emulated time passing too fast. - * Realtime triggers occur even when idle, so use them less frequently - * than VM triggers. - */ - timers_state.vm_clock_warp_start = -1; - timers_state.icount_rt_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL_RT, - icount_adjust_rt, NULL); - timer_mod(timers_state.icount_rt_timer, - qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000); - timers_state.icount_vm_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, - icount_adjust_vm, NULL); - timer_mod(timers_state.icount_vm_timer, - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + - NANOSECONDS_PER_SECOND / 10); -} - -void icount_notify_exit(void) -{ - if (icount_enabled() && current_cpu) { - qemu_cpu_kick(current_cpu); - qemu_clock_notify(QEMU_CLOCK_VIRTUAL); - } -} diff --git a/softmmu/meson.build b/softmmu/meson.build index c18b7ad738..3a64dd89de 100644 --- a/softmmu/meson.build +++ b/softmmu/meson.build @@ -6,10 +6,6 @@ specific_ss.add(when: 'CONFIG_SYSTEM_ONLY', if_true: [files( 'watchpoint.c', )]) -specific_ss.add(when: ['CONFIG_SYSTEM_ONLY', 'CONFIG_TCG'], if_true: [files( - 'icount.c', -)]) - system_ss.add(files( 'balloon.c', 'bootdevice.c',