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, 37 insertions, 0 deletions

diff --git a/tools/testing/shared/shared.h b/tools/testing/shared/shared.h
new file mode 100644
index 000000000..13fb4d399
--- /dev/null
+++ b/tools/testing/shared/shared.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SHARED_H__
+#define __SHARED_H__
+
+#include <linux/types.h>
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+
+#include <linux/gfp.h>
+#include <linux/rcupdate.h>
+
+#ifndef module_init
+#define module_init(x)
+#endif
+
+#ifndef module_exit
+#define module_exit(x)
+#endif
+
+#ifndef MODULE_AUTHOR
+#define MODULE_AUTHOR(x)
+#endif
+
+#ifndef MODULE_LICENSE
+#define MODULE_LICENSE(x)
+#endif
+
+#ifndef MODULE_DESCRIPTION
+#define MODULE_DESCRIPTION(x)
+#endif
+
+#ifndef dump_stack
+#define dump_stack()	assert(0)
+#endif
+
+#endif /* __SHARED_H__ */