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>

3 files changed, 122 insertions, 0 deletions

diff --git a/drivers/clk/imgtec/Kconfig b/drivers/clk/imgtec/Kconfig
new file mode 100644
index 000000000..c965fd091
--- /dev/null
+++ b/drivers/clk/imgtec/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config COMMON_CLK_BOSTON
+	bool "Clock driver for MIPS Boston boards"
+	depends on MIPS || COMPILE_TEST
+	select MFD_SYSCON
+	help
+	  Enable this to support the system & CPU clocks on the MIPS Boston
+	  development board from Imagination Technologies. These are simple
+	  fixed rate clocks whose rate is determined by reading a platform
+	  provided register.
diff --git a/drivers/clk/imgtec/Makefile b/drivers/clk/imgtec/Makefile
new file mode 100644
index 000000000..d2e81426c
--- /dev/null
+++ b/drivers/clk/imgtec/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_COMMON_CLK_BOSTON)		+= clk-boston.o
diff --git a/drivers/clk/imgtec/clk-boston.c b/drivers/clk/imgtec/clk-boston.c
new file mode 100644
index 000000000..f28c3ab93
--- /dev/null
+++ b/drivers/clk/imgtec/clk-boston.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2016-2017 Imagination Technologies
+ * Author: Paul Burton <paul.burton@mips.com>
+ */
+
+#define pr_fmt(fmt) "clk-boston: " fmt
+
+#include <linux/clk-provider.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+
+#include <dt-bindings/clock/boston-clock.h>
+
+#define BOSTON_PLAT_MMCMDIV		0x30
+# define BOSTON_PLAT_MMCMDIV_CLK0DIV	(0xff << 0)
+# define BOSTON_PLAT_MMCMDIV_INPUT	(0xff << 8)
+# define BOSTON_PLAT_MMCMDIV_MUL	(0xff << 16)
+# define BOSTON_PLAT_MMCMDIV_CLK1DIV	(0xff << 24)
+
+#define BOSTON_CLK_COUNT 3
+
+static u32 ext_field(u32 val, u32 mask)
+{
+	return (val & mask) >> (ffs(mask) - 1);
+}
+
+static void __init clk_boston_setup(struct device_node *np)
+{
+	unsigned long in_freq, cpu_freq, sys_freq;
+	uint mmcmdiv, mul, cpu_div, sys_div;
+	struct clk_hw_onecell_data *onecell;
+	struct regmap *regmap;
+	struct clk_hw *hw;
+	int err;
+
+	regmap = syscon_node_to_regmap(np->parent);
+	if (IS_ERR(regmap)) {
+		pr_err("failed to find regmap\n");
+		return;
+	}
+
+	err = regmap_read(regmap, BOSTON_PLAT_MMCMDIV, &mmcmdiv);
+	if (err) {
+		pr_err("failed to read mmcm_div register: %d\n", err);
+		return;
+	}
+
+	in_freq = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_INPUT) * 1000000;
+	mul = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_MUL);
+
+	sys_div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK0DIV);
+	sys_freq = mult_frac(in_freq, mul, sys_div);
+
+	cpu_div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK1DIV);
+	cpu_freq = mult_frac(in_freq, mul, cpu_div);
+
+	onecell = kzalloc_flex(*onecell, hws, BOSTON_CLK_COUNT);
+	if (!onecell)
+		return;
+
+	onecell->num = BOSTON_CLK_COUNT;
+
+	hw = clk_hw_register_fixed_rate(NULL, "input", NULL, 0, in_freq);
+	if (IS_ERR(hw)) {
+		pr_err("failed to register input clock: %pe\n", hw);
+		goto fail_input;
+	}
+	onecell->hws[BOSTON_CLK_INPUT] = hw;
+
+	hw = clk_hw_register_fixed_rate(NULL, "sys", "input", 0, sys_freq);
+	if (IS_ERR(hw)) {
+		pr_err("failed to register sys clock: %pe\n", hw);
+		goto fail_sys;
+	}
+	onecell->hws[BOSTON_CLK_SYS] = hw;
+
+	hw = clk_hw_register_fixed_rate(NULL, "cpu", "input", 0, cpu_freq);
+	if (IS_ERR(hw)) {
+		pr_err("failed to register cpu clock: %pe\n", hw);
+		goto fail_cpu;
+	}
+	onecell->hws[BOSTON_CLK_CPU] = hw;
+
+	err = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, onecell);
+	if (err) {
+		pr_err("failed to add DT provider: %d\n", err);
+		goto fail_clk_add;
+	}
+
+	return;
+
+fail_clk_add:
+	clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_CPU]);
+fail_cpu:
+	clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_SYS]);
+fail_sys:
+	clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_INPUT]);
+fail_input:
+	kfree(onecell);
+}
+
+/*
+ * Use CLK_OF_DECLARE so that this driver is probed early enough to provide the
+ * CPU frequency for use with the GIC or cop0 counters/timers.
+ */
+CLK_OF_DECLARE(clk_boston, "img,boston-clock", clk_boston_setup);