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, 50 insertions, 0 deletions

diff --git a/arch/m68k/coldfire/reset.c b/arch/m68k/coldfire/reset.c
new file mode 100644
index 000000000..6e5f8ab39
--- /dev/null
+++ b/arch/m68k/coldfire/reset.c
@@ -0,0 +1,50 @@
+/*
+ * reset.c  -- common ColdFire SoC reset support
+ *
+ * (C) Copyright 2012, Greg Ungerer <gerg@uclinux.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <asm/machdep.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+
+/*
+ *	There are 2 common methods amongst the ColdFure parts for reseting
+ *	the CPU. But there are couple of exceptions, the 5272 and the 547x
+ *	have something completely special to them, and we let their specific
+ *	subarch code handle them.
+ */
+
+#ifdef MCFSIM_SYPCR
+static void mcf_cpu_reset(void)
+{
+	local_irq_disable();
+	/* Set watchdog to soft reset, and enabled */
+	mcf_write8(0xc0, MCFSIM_SYPCR);
+	for (;;)
+		/* wait for watchdog to timeout */;
+}
+#endif
+
+#ifdef MCF_RCR
+static void mcf_cpu_reset(void)
+{
+	local_irq_disable();
+	mcf_write8(MCF_RCR_SWRESET, MCF_RCR);
+}
+#endif
+
+static int __init mcf_setup_reset(void)
+{
+	mach_reset = mcf_cpu_reset;
+	return 0;
+}
+
+arch_initcall(mcf_setup_reset);