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, 136 insertions, 0 deletions

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
new file mode 100644
index 000000000..fae4f8eac
--- /dev/null
+++ b/include/trace/events/ipi.h
@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM ipi
+
+#if !defined(_TRACE_IPI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_IPI_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(ipi_send_cpu,
+
+	TP_PROTO(const unsigned int cpu, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpu, callsite, callback),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, cpu)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__entry->cpu = cpu;
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpu=%u callsite=%pS callback=%pS",
+		  __entry->cpu, __entry->callsite, __entry->callback)
+);
+
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
+#ifdef CONFIG_HAVE_EXTRA_IPI_TRACEPOINTS
+/**
+ * ipi_raise - called when a smp cross call is made
+ *
+ * @mask: mask of recipient CPUs for the IPI
+ * @reason: string identifying the IPI purpose
+ *
+ * It is necessary for @reason to be a static string declared with
+ * __tracepoint_string.
+ */
+TRACE_EVENT(ipi_raise,
+
+	TP_PROTO(const struct cpumask *mask, const char *reason),
+
+	TP_ARGS(mask, reason),
+
+	TP_STRUCT__entry(
+		__cpumask(target_cpus)
+		__field(const char *, reason)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(target_cpus, cpumask_bits(mask));
+		__entry->reason = reason;
+	),
+
+	TP_printk("target_mask=%s (%s)", __get_cpumask(target_cpus), __entry->reason)
+);
+
+DECLARE_EVENT_CLASS(ipi_handler,
+
+	TP_PROTO(const char *reason),
+
+	TP_ARGS(reason),
+
+	TP_STRUCT__entry(
+		__field(const char *, reason)
+	),
+
+	TP_fast_assign(
+		__entry->reason = reason;
+	),
+
+	TP_printk("(%s)", __entry->reason)
+);
+
+/**
+ * ipi_entry - called immediately before the IPI handler
+ *
+ * @reason: string identifying the IPI purpose
+ *
+ * It is necessary for @reason to be a static string declared with
+ * __tracepoint_string, ideally the same as used with trace_ipi_raise
+ * for that IPI.
+ */
+DEFINE_EVENT(ipi_handler, ipi_entry,
+
+	TP_PROTO(const char *reason),
+
+	TP_ARGS(reason)
+);
+
+/**
+ * ipi_exit - called immediately after the IPI handler returns
+ *
+ * @reason: string identifying the IPI purpose
+ *
+ * It is necessary for @reason to be a static string declared with
+ * __tracepoint_string, ideally the same as used with trace_ipi_raise for
+ * that IPI.
+ */
+DEFINE_EVENT(ipi_handler, ipi_exit,
+
+	TP_PROTO(const char *reason),
+
+	TP_ARGS(reason)
+);
+#endif /* CONFIG_HAVE_EXTRA_IPI_TRACEPOINTS */
+
+#endif /* _TRACE_IPI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>