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, 41 insertions, 0 deletions

diff --git a/arch/arm/mach-s3c/dev-uart.c b/arch/arm/mach-s3c/dev-uart.c
new file mode 100644
index 000000000..3d1f7f2fd
--- /dev/null
+++ b/arch/arm/mach-s3c/dev-uart.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+//	originally from arch/arm/plat-s3c24xx/devs.c
+//
+// Copyright (c) 2004 Simtec Electronics
+//	Ben Dooks <ben@simtec.co.uk>
+//
+// Base S3C24XX platform device definitions
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#include "devs.h"
+
+/* uart devices */
+
+static struct platform_device s3c24xx_uart_device0 = {
+	.id		= 0,
+};
+
+static struct platform_device s3c24xx_uart_device1 = {
+	.id		= 1,
+};
+
+static struct platform_device s3c24xx_uart_device2 = {
+	.id		= 2,
+};
+
+static struct platform_device s3c24xx_uart_device3 = {
+	.id		= 3,
+};
+
+struct platform_device *s3c24xx_uart_src[4] = {
+	&s3c24xx_uart_device0,
+	&s3c24xx_uart_device1,
+	&s3c24xx_uart_device2,
+	&s3c24xx_uart_device3,
+};
+
+struct platform_device *s3c24xx_uart_devs[4] = {
+};