Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 264 insertions, 0 deletions

diff --git a/trace/control.h b/trace/control.h
new file mode 100644
index 000000000..23b8393b2
--- /dev/null
+++ b/trace/control.h
@@ -0,0 +1,264 @@
+/*
+ * Interface for configuring and controlling the state of tracing events.
+ *
+ * Copyright (C) 2011-2016 Lluís Vilanova <vilanova@ac.upc.edu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef TRACE__CONTROL_H
+#define TRACE__CONTROL_H
+
+#include "event-internal.h"
+
+typedef struct TraceEventIter {
+    /* iter state */
+    size_t event;
+    size_t group;
+    /* filter conditions */
+    size_t group_id;
+    const char *pattern;
+} TraceEventIter;
+
+
+/**
+ * trace_event_iter_init_all:
+ * @iter: the event iterator struct
+ *
+ * Initialize the event iterator struct @iter,
+ * for all events.
+ */
+void trace_event_iter_init_all(TraceEventIter *iter);
+
+/**
+ * trace_event_iter_init_pattern:
+ * @iter: the event iterator struct
+ * @pattern: pattern to filter events on name
+ *
+ * Initialize the event iterator struct @iter,
+ * using @pattern to filter out events
+ * with non-matching names.
+ */
+void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern);
+
+/**
+ * trace_event_iter_init_group:
+ * @iter: the event iterator struct
+ * @group_id: group_id to filter events by group.
+ *
+ * Initialize the event iterator struct @iter,
+ * using @group_id to filter for events in the group.
+ */
+void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id);
+
+/**
+ * trace_event_iter_next:
+ * @iter: the event iterator struct
+ *
+ * Get the next event, if any. When this returns NULL,
+ * the iterator should no longer be used.
+ *
+ * Returns: the next event, or NULL if no more events exist
+ */
+TraceEvent *trace_event_iter_next(TraceEventIter *iter);
+
+
+/**
+ * trace_event_name:
+ * @id: Event name.
+ *
+ * Search an event by its name.
+ *
+ * Returns: pointer to #TraceEvent or NULL if not found.
+ */
+TraceEvent *trace_event_name(const char *name);
+
+/**
+ * trace_event_is_pattern:
+ *
+ * Whether the given string is an event name pattern.
+ */
+static bool trace_event_is_pattern(const char *str);
+
+
+/**
+ * trace_event_get_id:
+ *
+ * Get the identifier of an event.
+ */
+static uint32_t trace_event_get_id(TraceEvent *ev);
+
+/**
+ * trace_event_get_vcpu_id:
+ *
+ * Get the per-vCPU identifier of an event.
+ *
+ * Special value #TRACE_VCPU_EVENT_NONE means the event is not vCPU-specific
+ * (does not have the "vcpu" property).
+ */
+static uint32_t trace_event_get_vcpu_id(TraceEvent *ev);
+
+/**
+ * trace_event_is_vcpu:
+ *
+ * Whether this is a per-vCPU event.
+ */
+static bool trace_event_is_vcpu(TraceEvent *ev);
+
+/**
+ * trace_event_get_name:
+ *
+ * Get the name of an event.
+ */
+static const char * trace_event_get_name(TraceEvent *ev);
+
+/**
+ * trace_event_get_state:
+ * @id: Event identifier name.
+ *
+ * Get the tracing state of an event, both static and the QEMU dynamic state.
+ *
+ * If the event has the disabled property, the check will have no performance
+ * impact.
+ */
+#define trace_event_get_state(id)                       \
+    ((id ##_ENABLED) && trace_event_get_state_dynamic_by_id(id))
+
+/**
+ * trace_event_get_state_backends:
+ * @id: Event identifier name.
+ *
+ * Get the tracing state of an event, both static and dynamic state from all
+ * compiled-in backends.
+ *
+ * If the event has the disabled property, the check will have no performance
+ * impact.
+ *
+ * Returns: true if at least one backend has the event enabled and the event
+ * does not have the disabled property.
+ */
+#define trace_event_get_state_backends(id)              \
+    ((id ##_ENABLED) && id ##_BACKEND_DSTATE())
+
+/**
+ * trace_event_get_state_static:
+ * @id: Event identifier.
+ *
+ * Get the static tracing state of an event.
+ *
+ * Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
+ * be set to 1 or 0 according to the presence of the disabled property).
+ */
+static bool trace_event_get_state_static(TraceEvent *ev);
+
+/**
+ * trace_event_get_state_dynamic:
+ *
+ * Get the dynamic tracing state of an event.
+ *
+ * If the event has the 'vcpu' property, gets the OR'ed state of all vCPUs.
+ */
+static bool trace_event_get_state_dynamic(TraceEvent *ev);
+
+/**
+ * trace_event_set_state_dynamic:
+ *
+ * Set the dynamic tracing state of an event.
+ *
+ * If the event has the 'vcpu' property, sets the state on all vCPUs.
+ *
+ * Pre-condition: trace_event_get_state_static(ev) == true
+ */
+void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
+
+/**
+ * trace_event_set_vcpu_state_dynamic:
+ *
+ * Set the dynamic tracing state of an event for the given vCPU.
+ *
+ * Pre-condition: trace_event_get_vcpu_state_static(ev) == true
+ *
+ * Note: Changes for execution-time events with the 'tcg' property will not be
+ *       propagated until the next TB is executed (iff executing in TCG mode).
+ */
+void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
+                                        TraceEvent *ev, bool state);
+
+
+
+/**
+ * trace_init_backends:
+ *
+ * Initialize the tracing backend.
+ *
+ * Returns: Whether the backends could be successfully initialized.
+ */
+bool trace_init_backends(void);
+
+/**
+ * trace_init_file:
+ *
+ * Record the name of the output file for the tracing backend.
+ * Exits if no selected backend does not support specifying the
+ * output file, and a file was specified with "-trace file=...".
+ */
+void trace_init_file(void);
+
+/**
+ * trace_init_vcpu:
+ * @vcpu: Added vCPU.
+ *
+ * Set initial dynamic event state for a hot-plugged vCPU.
+ */
+void trace_init_vcpu(CPUState *vcpu);
+
+/**
+ * trace_fini_vcpu:
+ * @vcpu: Removed vCPU.
+ *
+ * Disable dynamic event state for a hot-unplugged vCPU.
+ */
+void trace_fini_vcpu(CPUState *vcpu);
+
+/**
+ * trace_list_events:
+ * @f: Where to send output.
+ *
+ * List all available events.
+ */
+void trace_list_events(FILE *f);
+
+/**
+ * trace_enable_events:
+ * @line_buf: A string with a glob pattern of events to be enabled or,
+ *            if the string starts with '-', disabled.
+ *
+ * Enable or disable matching events.
+ */
+void trace_enable_events(const char *line_buf);
+
+/**
+ * Definition of QEMU options describing trace subsystem configuration
+ */
+extern QemuOptsList qemu_trace_opts;
+
+/**
+ * trace_opt_parse:
+ * @optarg: A string argument of --trace command line argument
+ *
+ * Initialize tracing subsystem.
+ */
+void trace_opt_parse(const char *optarg);
+
+/**
+ * trace_get_vcpu_event_count:
+ *
+ * Return the number of known vcpu-specific events
+ */
+uint32_t trace_get_vcpu_event_count(void);
+
+
+#include "control-internal.h"
+
+#endif /* TRACE__CONTROL_H */