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/power/cpu.c b/arch/mips/power/cpu.c
new file mode 100644
index 000000000..d8ef7778e
--- /dev/null
+++ b/arch/mips/power/cpu.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Suspend support specific for mips.
+ *
+ * Copyright (C) 2009 Lemote Inc.
+ * Author: Hu Hongbing <huhb@lemote.com>
+ *	   Wu Zhangjin <wuzhangjin@gmail.com>
+ */
+#include <linux/suspend.h>
+#include <asm/sections.h>
+#include <asm/fpu.h>
+#include <asm/dsp.h>
+
+static u32 saved_status;
+struct pt_regs saved_regs;
+
+void save_processor_state(void)
+{
+	saved_status = read_c0_status();
+
+	if (is_fpu_owner())
+		save_fp(current);
+
+	save_dsp(current);
+}
+
+void restore_processor_state(void)
+{
+	write_c0_status(saved_status);
+
+	if (is_fpu_owner())
+		restore_fp(current);
+
+	restore_dsp(current);
+}
+
+int pfn_is_nosave(unsigned long pfn)
+{
+	unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
+	unsigned long nosave_end_pfn = PFN_UP(__pa(&__nosave_end));
+
+	return	(pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
+}