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, 43 insertions, 0 deletions

diff --git a/arch/mips/ralink/reset.c b/arch/mips/ralink/reset.c
new file mode 100644
index 000000000..4875637ef
--- /dev/null
+++ b/arch/mips/ralink/reset.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) 2008-2009 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ * Copyright (C) 2013 John Crispin <john@phrozen.org>
+ */
+
+#include <linux/pm.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/delay.h>
+
+#include <asm/reboot.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+
+/* Reset Control */
+#define SYSC_REG_RESET_CTRL	0x034
+
+#define RSTCTL_RESET_PCI	BIT(26)
+#define RSTCTL_RESET_SYSTEM	BIT(0)
+
+static void ralink_restart(char *command)
+{
+	if (IS_ENABLED(CONFIG_PCI)) {
+		rt_sysc_m32(0, RSTCTL_RESET_PCI, SYSC_REG_RESET_CTRL);
+		mdelay(50);
+	}
+
+	local_irq_disable();
+	rt_sysc_w32(RSTCTL_RESET_SYSTEM, SYSC_REG_RESET_CTRL);
+	unreachable();
+}
+
+static int __init mips_reboot_setup(void)
+{
+	_machine_restart = ralink_restart;
+
+	return 0;
+}
+
+arch_initcall(mips_reboot_setup);