2 * QEMU TCG Single Threaded vCPUs implementation using instruction counting
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 * Copyright (c) 2014 Red Hat Inc.
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 #include "qemu/osdep.h"
27 #include "sysemu/replay.h"
28 #include "sysemu/cpu-timers.h"
29 #include "qemu/main-loop.h"
30 #include "qemu/guest-random.h"
31 #include "exec/exec-all.h"
33 #include "tcg-accel-ops.h"
34 #include "tcg-accel-ops-icount.h"
35 #include "tcg-accel-ops-rr.h"
37 static int64_t icount_get_limit(void)
41 if (replay_mode
!= REPLAY_MODE_PLAY
) {
43 * Include all the timers, because they may need an attention.
44 * Too long CPU execution may create unnecessary delay in UI.
46 deadline
= qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL
,
48 /* Check realtime timers, because they help with input processing */
49 deadline
= qemu_soonest_timeout(deadline
,
50 qemu_clock_deadline_ns_all(QEMU_CLOCK_REALTIME
,
51 QEMU_TIMER_ATTR_ALL
));
54 * Maintain prior (possibly buggy) behaviour where if no deadline
55 * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
56 * INT32_MAX nanoseconds ahead, we still use INT32_MAX
59 if ((deadline
< 0) || (deadline
> INT32_MAX
)) {
63 return icount_round(deadline
);
65 return replay_get_instructions();
69 static void icount_notify_aio_contexts(void)
71 /* Wake up other AioContexts. */
72 qemu_clock_notify(QEMU_CLOCK_VIRTUAL
);
73 qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL
);
76 void icount_handle_deadline(void)
78 assert(qemu_in_vcpu_thread());
79 int64_t deadline
= qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL
,
83 * Instructions, interrupts, and exceptions are processed in cpu-exec.
84 * Don't interrupt cpu thread, when these events are waiting
85 * (i.e., there is no checkpoint)
88 icount_notify_aio_contexts();
92 void icount_prepare_for_run(CPUState
*cpu
)
97 * These should always be cleared by icount_process_data after
98 * each vCPU execution. However u16.high can be raised
99 * asynchronously by cpu_exit/cpu_interrupt/tcg_handle_interrupt
101 g_assert(cpu_neg(cpu
)->icount_decr
.u16
.low
== 0);
102 g_assert(cpu
->icount_extra
== 0);
104 cpu
->icount_budget
= icount_get_limit();
105 insns_left
= MIN(0xffff, cpu
->icount_budget
);
106 cpu_neg(cpu
)->icount_decr
.u16
.low
= insns_left
;
107 cpu
->icount_extra
= cpu
->icount_budget
- insns_left
;
111 if (cpu
->icount_budget
== 0) {
112 icount_notify_aio_contexts();
116 void icount_process_data(CPUState
*cpu
)
118 /* Account for executed instructions */
121 /* Reset the counters */
122 cpu_neg(cpu
)->icount_decr
.u16
.low
= 0;
123 cpu
->icount_extra
= 0;
124 cpu
->icount_budget
= 0;
126 replay_account_executed_instructions();
128 replay_mutex_unlock();
131 void icount_handle_interrupt(CPUState
*cpu
, int mask
)
133 int old_mask
= cpu
->interrupt_request
;
135 tcg_handle_interrupt(cpu
, mask
);
136 if (qemu_cpu_is_self(cpu
) &&
138 && (mask
& ~old_mask
) != 0) {
139 cpu_abort(cpu
, "Raised interrupt while not in I/O function");