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>

9 files changed, 176 insertions, 0 deletions

diff --git a/tools/include/asm/alternative.h b/tools/include/asm/alternative.h
new file mode 100644
index 000000000..8e548ac8f
--- /dev/null
+++ b/tools/include/asm/alternative.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_ASM_ALTERNATIVE_ASM_H
+#define _TOOLS_ASM_ALTERNATIVE_ASM_H
+
+#if defined(__s390x__)
+#ifdef __ASSEMBLY__
+.macro ALTERNATIVE oldinstr, newinstr, feature
+	\oldinstr
+.endm
+#endif
+#else
+
+/* Just disable it so we can build arch/x86/lib/memcpy_64.S for perf bench: */
+
+#define ALTERNATIVE #
+
+#endif
+
+#endif
diff --git a/tools/include/asm/atomic.h b/tools/include/asm/atomic.h
new file mode 100644
index 000000000..8c9bfffd4
--- /dev/null
+++ b/tools/include/asm/atomic.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TOOLS_LINUX_ASM_ATOMIC_H
+#define __TOOLS_LINUX_ASM_ATOMIC_H
+
+#if defined(__i386__) || defined(__x86_64__)
+#include "../../arch/x86/include/asm/atomic.h"
+#else
+#include <asm-generic/atomic-gcc.h>
+#endif
+
+#endif /* __TOOLS_LINUX_ASM_ATOMIC_H */
diff --git a/tools/include/asm/barrier.h b/tools/include/asm/barrier.h
new file mode 100644
index 000000000..0c21678ac
--- /dev/null
+++ b/tools/include/asm/barrier.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/compiler.h>
+#if defined(__i386__) || defined(__x86_64__)
+#include "../../arch/x86/include/asm/barrier.h"
+#elif defined(__arm__)
+#include "../../arch/arm/include/asm/barrier.h"
+#elif defined(__aarch64__)
+#include "../../arch/arm64/include/asm/barrier.h"
+#elif defined(__powerpc__)
+#include "../../arch/powerpc/include/asm/barrier.h"
+#elif defined(__riscv)
+#include "../../arch/riscv/include/asm/barrier.h"
+#elif defined(__s390__)
+#include "../../arch/s390/include/asm/barrier.h"
+#elif defined(__sh__)
+#include "../../arch/sh/include/asm/barrier.h"
+#elif defined(__sparc__)
+#include "../../arch/sparc/include/asm/barrier.h"
+#elif defined(__tile__)
+#include "../../arch/tile/include/asm/barrier.h"
+#elif defined(__alpha__)
+#include "../../arch/alpha/include/asm/barrier.h"
+#elif defined(__mips__)
+#include "../../arch/mips/include/asm/barrier.h"
+#elif defined(__ia64__)
+#include "../../arch/ia64/include/asm/barrier.h"
+#elif defined(__xtensa__)
+#include "../../arch/xtensa/include/asm/barrier.h"
+#else
+#include <asm-generic/barrier.h>
+#endif
+
+/*
+ * Generic fallback smp_*() definitions for archs that haven't
+ * been updated yet.
+ */
+
+#ifndef smp_rmb
+# define smp_rmb()	rmb()
+#endif
+
+#ifndef smp_wmb
+# define smp_wmb()	wmb()
+#endif
+
+#ifndef smp_mb
+# define smp_mb()	mb()
+#endif
+
+#ifndef smp_store_release
+# define smp_store_release(p, v)		\
+do {						\
+	smp_mb();				\
+	WRITE_ONCE(*p, v);			\
+} while (0)
+#endif
+
+#ifndef smp_load_acquire
+# define smp_load_acquire(p)			\
+({						\
+	typeof(*p) ___p1 = READ_ONCE(*p);	\
+	smp_mb();				\
+	___p1;					\
+})
+#endif
diff --git a/tools/include/asm/bug.h b/tools/include/asm/bug.h
new file mode 100644
index 000000000..550223f0a
--- /dev/null
+++ b/tools/include/asm/bug.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_ASM_BUG_H
+#define _TOOLS_ASM_BUG_H
+
+#include <linux/compiler.h>
+#include <stdio.h>
+
+#define __WARN_printf(arg...)	do { fprintf(stderr, arg); } while (0)
+
+#define WARN(condition, format...) ({		\
+	int __ret_warn_on = !!(condition);	\
+	if (unlikely(__ret_warn_on))		\
+		__WARN_printf(format);		\
+	unlikely(__ret_warn_on);		\
+})
+
+#define WARN_ON(condition) ({					\
+	int __ret_warn_on = !!(condition);			\
+	if (unlikely(__ret_warn_on))				\
+		__WARN_printf("assertion failed at %s:%d\n",	\
+				__FILE__, __LINE__);		\
+	unlikely(__ret_warn_on);				\
+})
+
+#define WARN_ON_ONCE(condition) ({			\
+	static int __warned;				\
+	int __ret_warn_once = !!(condition);		\
+							\
+	if (unlikely(__ret_warn_once && !__warned)) {	\
+		__warned = true;			\
+		WARN_ON(1);				\
+	}						\
+	unlikely(__ret_warn_once);			\
+})
+
+#define WARN_ONCE(condition, format...)	({	\
+	static int __warned;			\
+	int __ret_warn_once = !!(condition);	\
+						\
+	if (unlikely(__ret_warn_once))		\
+		if (WARN(!__warned, format)) 	\
+			__warned = 1;		\
+	unlikely(__ret_warn_once);		\
+})
+
+#endif /* _TOOLS_ASM_BUG_H */
diff --git a/tools/include/asm/export.h b/tools/include/asm/export.h
new file mode 100644
index 000000000..2cb1a0d83
--- /dev/null
+++ b/tools/include/asm/export.h
@@ -0,0 +1,7 @@
+#ifndef _TOOLS_ASM_EXPORT_H
+#define _TOOLS_ASM_EXPORT_H
+
+#define EXPORT_SYMBOL(x)
+#define EXPORT_SYMBOL_GPL(x)
+
+#endif /* _TOOLS_ASM_EXPORT_H */
diff --git a/tools/include/asm/io.h b/tools/include/asm/io.h
new file mode 100644
index 000000000..eed5066f2
--- /dev/null
+++ b/tools/include/asm/io.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_ASM_IO_H
+#define _TOOLS_ASM_IO_H
+
+#if defined(__i386__) || defined(__x86_64__)
+#include "../../arch/x86/include/asm/io.h"
+#else
+#include <asm-generic/io.h>
+#endif
+
+#endif /* _TOOLS_ASM_IO_H */
diff --git a/tools/include/asm/rwonce.h b/tools/include/asm/rwonce.h
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tools/include/asm/rwonce.h
diff --git a/tools/include/asm/sections.h b/tools/include/asm/sections.h
new file mode 100644
index 000000000..a80643d7a
--- /dev/null
+++ b/tools/include/asm/sections.h
@@ -0,0 +1,4 @@
+#ifndef __TOOLS_INCLUDE_LINUX_ASM_SECTIONS_H
+#define __TOOLS_INCLUDE_LINUX_ASM_SECTIONS_H
+
+#endif /* __TOOLS_INCLUDE_LINUX_ASM_SECTIONS_H */
diff --git a/tools/include/asm/timex.h b/tools/include/asm/timex.h
new file mode 100644
index 000000000..5adfe3c6d
--- /dev/null
+++ b/tools/include/asm/timex.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TOOLS_LINUX_ASM_TIMEX_H
+#define __TOOLS_LINUX_ASM_TIMEX_H
+
+#include <time.h>
+
+#define cycles_t clock_t
+
+static inline cycles_t get_cycles(void)
+{
+	return clock();
+}
+#endif // __TOOLS_LINUX_ASM_TIMEX_H