KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/include/rv/automata.h b/include/rv/automata.h
new file mode 100644
index 000000000..4a4eb40cf
--- /dev/null
+++ b/include/rv/automata.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira  <bristot@kernel.org>
+ *
+ * Deterministic automata helper functions, to be used with the automata
+ * models in C generated by the dot2k tool.
+ */
+
+#ifndef _RV_AUTOMATA_H
+#define _RV_AUTOMATA_H
+
+#ifndef MONITOR_NAME
+#error "MONITOR_NAME macro is not defined. Did you include $(MODEL_NAME).h generated by rvgen?"
+#endif
+
+#define RV_AUTOMATON_NAME CONCATENATE(automaton_, MONITOR_NAME)
+#define EVENT_MAX CONCATENATE(event_max_, MONITOR_NAME)
+#define STATE_MAX CONCATENATE(state_max_, MONITOR_NAME)
+#define events CONCATENATE(events_, MONITOR_NAME)
+#define states CONCATENATE(states_, MONITOR_NAME)
+
+/*
+ * model_get_state_name - return the (string) name of the given state
+ */
+static char *model_get_state_name(enum states state)
+{
+	if ((state < 0) || (state >= STATE_MAX))
+		return "INVALID";
+
+	return RV_AUTOMATON_NAME.state_names[state];
+}
+
+/*
+ * model_get_event_name - return the (string) name of the given event
+ */
+static char *model_get_event_name(enum events event)
+{
+	if ((event < 0) || (event >= EVENT_MAX))
+		return "INVALID";
+
+	return RV_AUTOMATON_NAME.event_names[event];
+}
+
+/*
+ * model_get_initial_state - return the automaton's initial state
+ */
+static inline enum states model_get_initial_state(void)
+{
+	return RV_AUTOMATON_NAME.initial_state;
+}
+
+/*
+ * model_get_next_state - process an automaton event occurrence
+ *
+ * Given the current state (curr_state) and the event (event), returns
+ * the next state, or INVALID_STATE in case of error.
+ */
+static inline enum states model_get_next_state(enum states curr_state,
+					enum events event)
+{
+	if ((curr_state < 0) || (curr_state >= STATE_MAX))
+		return INVALID_STATE;
+
+	if ((event < 0) || (event >= EVENT_MAX))
+		return INVALID_STATE;
+
+	return RV_AUTOMATON_NAME.function[curr_state][event];
+}
+
+/*
+ * model_is_final_state - check if the given state is a final state
+ */
+static inline bool model_is_final_state(enum states state)
+{
+	if ((state < 0) || (state >= STATE_MAX))
+		return 0;
+
+	return RV_AUTOMATON_NAME.final_states[state];
+}
+
+#endif