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, 54 insertions, 0 deletions

diff --git a/tools/testing/memblock/internal.h b/tools/testing/memblock/internal.h
new file mode 100644
index 000000000..f1974e009
--- /dev/null
+++ b/tools/testing/memblock/internal.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _MM_INTERNAL_H
+#define _MM_INTERNAL_H
+
+/*
+ * Enable memblock_dbg() messages
+ */
+#ifdef MEMBLOCK_DEBUG
+static int memblock_debug = 1;
+#endif
+
+#define pr_warn_ratelimited(fmt, ...)    printf(fmt, ##__VA_ARGS__)
+
+#define K(x) ((x) << (PAGE_SHIFT-10))
+
+bool mirrored_kernelcore = false;
+
+struct page {};
+static inline void *page_address(struct page *page)
+{
+	BUG();
+	return page;
+}
+
+static inline struct page *virt_to_page(void *virt)
+{
+	BUG();
+	return virt;
+}
+
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn)			 \
+	for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++)
+
+static inline void *kasan_reset_tag(const void *addr)
+{
+	return (void *)addr;
+}
+
+static inline bool __is_kernel(unsigned long addr)
+{
+	return false;
+}
+
+#define for_each_valid_pfn(pfn, start_pfn, end_pfn)                     \
+       for ((pfn) = (start_pfn); (pfn) < (end_pfn); (pfn)++)
+
+#define __SetPageReserved(p)	((void)(p))
+
+static inline bool kho_scratch_overlap(phys_addr_t phys, size_t size)
+{
+	return false;
+}
+
+#endif