1 files changed, 147 insertions, 0 deletions
diff --git a/accel/tcg/tcg-cpus-icount.c b/accel/tcg/tcg-cpus-icount.c
new file mode 100644
index 0000000000..d3af3afb6d
--- /dev/null
+++ b/accel/tcg/tcg-cpus-icount.c
@@ -0,0 +1,147 @@
+/*
+ * QEMU TCG Single Threaded vCPUs implementation using instruction counting
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2014 Red Hat Inc.
+ *
+ * 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-common.h"
+#include "sysemu/tcg.h"
+#include "sysemu/replay.h"
+#include "qemu/main-loop.h"
+#include "qemu/guest-random.h"
+#include "exec/exec-all.h"
+#include "hw/boards.h"
+
+#include "tcg-cpus.h"
+#include "tcg-cpus-icount.h"
+#include "tcg-cpus-rr.h"
+
+static int64_t tcg_get_icount_limit(void)
+{
+    int64_t deadline;
+
+    if (replay_mode != REPLAY_MODE_PLAY) {
+        /*
+         * Include all the timers, because they may need an attention.
+         * Too long CPU execution may create unnecessary delay in UI.
+         */
+        deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+                                              QEMU_TIMER_ATTR_ALL);
+        /* Check realtime timers, because they help with input processing */
+        deadline = qemu_soonest_timeout(deadline,
+                qemu_clock_deadline_ns_all(QEMU_CLOCK_REALTIME,
+                                           QEMU_TIMER_ATTR_ALL));
+
+        /*
+         * Maintain prior (possibly buggy) behaviour where if no deadline
+         * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more than
+         * INT32_MAX nanoseconds ahead, we still use INT32_MAX
+         * nanoseconds.
+         */
+        if ((deadline < 0) || (deadline > INT32_MAX)) {
+            deadline = INT32_MAX;
+        }
+
+        return icount_round(deadline);
+    } else {
+        return replay_get_instructions();
+    }
+}
+
+static void notify_aio_contexts(void)
+{
+    /* Wake up other AioContexts.  */
+    qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
+    qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
+}
+
+void handle_icount_deadline(void)
+{
+    assert(qemu_in_vcpu_thread());
+    int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+                                                  QEMU_TIMER_ATTR_ALL);
+
+    if (deadline == 0) {
+        notify_aio_contexts();
+    }
+}
+
+void prepare_icount_for_run(CPUState *cpu)
+{
+    int insns_left;
+
+    /*
+     * These should always be cleared by process_icount_data after
+     * each vCPU execution. However u16.high can be raised
+     * asynchronously by cpu_exit/cpu_interrupt/tcg_handle_interrupt
+     */
+    g_assert(cpu_neg(cpu)->icount_decr.u16.low == 0);
+    g_assert(cpu->icount_extra == 0);
+
+    cpu->icount_budget = tcg_get_icount_limit();
+    insns_left = MIN(0xffff, cpu->icount_budget);
+    cpu_neg(cpu)->icount_decr.u16.low = insns_left;
+    cpu->icount_extra = cpu->icount_budget - insns_left;
+
+    replay_mutex_lock();
+
+    if (cpu->icount_budget == 0 && replay_has_checkpoint()) {
+        notify_aio_contexts();
+    }
+}
+
+void process_icount_data(CPUState *cpu)
+{
+    /* Account for executed instructions */
+    icount_update(cpu);
+
+    /* Reset the counters */
+    cpu_neg(cpu)->icount_decr.u16.low = 0;
+    cpu->icount_extra = 0;
+    cpu->icount_budget = 0;
+
+    replay_account_executed_instructions();
+
+    replay_mutex_unlock();
+}
+
+static void icount_handle_interrupt(CPUState *cpu, int mask)
+{
+    int old_mask = cpu->interrupt_request;
+
+    tcg_handle_interrupt(cpu, mask);
+    if (qemu_cpu_is_self(cpu) &&
+        !cpu->can_do_io
+        && (mask & ~old_mask) != 0) {
+        cpu_abort(cpu, "Raised interrupt while not in I/O function");
+    }
+}
+
+const CpusAccel tcg_cpus_icount = {
+    .create_vcpu_thread = tcg_start_vcpu_thread,
+    .kick_vcpu_thread = qemu_cpu_kick_rr_cpus,
+
+    .handle_interrupt = icount_handle_interrupt,
+    .get_virtual_clock = icount_get,
+    .get_elapsed_ticks = icount_get,
+};