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, 127 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/trace.h b/arch/powerpc/kvm/trace.h
new file mode 100644
index 000000000..ea1d7c808
--- /dev/null
+++ b/arch/powerpc/kvm/trace.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#if !defined(_TRACE_KVM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KVM_H
+
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM kvm
+
+/*
+ * Tracepoint for guest mode entry.
+ */
+TRACE_EVENT(kvm_ppc_instr,
+	TP_PROTO(unsigned int inst, unsigned long _pc, unsigned int emulate),
+	TP_ARGS(inst, _pc, emulate),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	inst		)
+		__field(	unsigned long,	pc		)
+		__field(	unsigned int,	emulate		)
+	),
+
+	TP_fast_assign(
+		__entry->inst		= inst;
+		__entry->pc		= _pc;
+		__entry->emulate	= emulate;
+	),
+
+	TP_printk("inst %u pc 0x%lx emulate %u\n",
+		  __entry->inst, __entry->pc, __entry->emulate)
+);
+
+TRACE_EVENT(kvm_stlb_inval,
+	TP_PROTO(unsigned int stlb_index),
+	TP_ARGS(stlb_index),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	stlb_index	)
+	),
+
+	TP_fast_assign(
+		__entry->stlb_index	= stlb_index;
+	),
+
+	TP_printk("stlb_index %u", __entry->stlb_index)
+);
+
+TRACE_EVENT(kvm_stlb_write,
+	TP_PROTO(unsigned int victim, unsigned int tid, unsigned int word0,
+		 unsigned int word1, unsigned int word2),
+	TP_ARGS(victim, tid, word0, word1, word2),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	victim		)
+		__field(	unsigned int,	tid		)
+		__field(	unsigned int,	word0		)
+		__field(	unsigned int,	word1		)
+		__field(	unsigned int,	word2		)
+	),
+
+	TP_fast_assign(
+		__entry->victim		= victim;
+		__entry->tid		= tid;
+		__entry->word0		= word0;
+		__entry->word1		= word1;
+		__entry->word2		= word2;
+	),
+
+	TP_printk("victim %u tid %u w0 %u w1 %u w2 %u",
+		__entry->victim, __entry->tid, __entry->word0,
+		__entry->word1, __entry->word2)
+);
+
+TRACE_EVENT(kvm_gtlb_write,
+	TP_PROTO(unsigned int gtlb_index, unsigned int tid, unsigned int word0,
+		 unsigned int word1, unsigned int word2),
+	TP_ARGS(gtlb_index, tid, word0, word1, word2),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	gtlb_index	)
+		__field(	unsigned int,	tid		)
+		__field(	unsigned int,	word0		)
+		__field(	unsigned int,	word1		)
+		__field(	unsigned int,	word2		)
+	),
+
+	TP_fast_assign(
+		__entry->gtlb_index	= gtlb_index;
+		__entry->tid		= tid;
+		__entry->word0		= word0;
+		__entry->word1		= word1;
+		__entry->word2		= word2;
+	),
+
+	TP_printk("gtlb_index %u tid %u w0 %u w1 %u w2 %u",
+		__entry->gtlb_index, __entry->tid, __entry->word0,
+		__entry->word1, __entry->word2)
+);
+
+TRACE_EVENT(kvm_check_requests,
+	TP_PROTO(struct kvm_vcpu *vcpu),
+	TP_ARGS(vcpu),
+
+	TP_STRUCT__entry(
+		__field(	__u32,	cpu_nr		)
+		__field(	__u32,	requests	)
+	),
+
+	TP_fast_assign(
+		__entry->cpu_nr		= vcpu->vcpu_id;
+		__entry->requests	= vcpu->requests;
+	),
+
+	TP_printk("vcpu=%x requests=%x",
+		__entry->cpu_nr, __entry->requests)
+);
+
+#endif /* _TRACE_KVM_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>