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, 227 insertions, 0 deletions

diff --git a/drivers/net/phy/nxp-cbtx.c b/drivers/net/phy/nxp-cbtx.c
new file mode 100644
index 000000000..3286fcb4f
--- /dev/null
+++ b/drivers/net/phy/nxp-cbtx.c
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Driver for 100BASE-TX PHY embedded into NXP SJA1110 switch
+ *
+ * Copyright 2022-2023 NXP
+ */
+
+#include <linux/kernel.h>
+#include <linux/mii.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define PHY_ID_CBTX_SJA1110			0x001bb020
+
+/* Registers */
+#define  CBTX_MODE_CTRL_STAT			0x11
+#define  CBTX_PDOWN_CTRL			0x18
+#define  CBTX_RX_ERR_COUNTER			0x1a
+#define  CBTX_IRQ_STAT				0x1d
+#define  CBTX_IRQ_ENABLE			0x1e
+
+/* Fields */
+#define CBTX_MODE_CTRL_STAT_AUTO_MDIX_EN	BIT(7)
+#define CBTX_MODE_CTRL_STAT_MDIX_MODE		BIT(6)
+
+#define CBTX_PDOWN_CTL_TRUE_PDOWN		BIT(0)
+
+#define CBTX_IRQ_ENERGYON			BIT(7)
+#define CBTX_IRQ_AN_COMPLETE			BIT(6)
+#define CBTX_IRQ_REM_FAULT			BIT(5)
+#define CBTX_IRQ_LINK_DOWN			BIT(4)
+#define CBTX_IRQ_AN_LP_ACK			BIT(3)
+#define CBTX_IRQ_PARALLEL_DETECT_FAULT		BIT(2)
+#define CBTX_IRQ_AN_PAGE_RECV			BIT(1)
+
+static int cbtx_soft_reset(struct phy_device *phydev)
+{
+	int ret;
+
+	/* Can't soft reset unless we remove PHY from true power down mode */
+	ret = phy_clear_bits(phydev, CBTX_PDOWN_CTRL,
+			     CBTX_PDOWN_CTL_TRUE_PDOWN);
+	if (ret)
+		return ret;
+
+	return genphy_soft_reset(phydev);
+}
+
+static int cbtx_config_init(struct phy_device *phydev)
+{
+	/* Wait for cbtx_config_aneg() to kick in and apply this */
+	phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
+
+	return 0;
+}
+
+static int cbtx_mdix_status(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = phy_read(phydev, CBTX_MODE_CTRL_STAT);
+	if (ret < 0)
+		return ret;
+
+	if (ret & CBTX_MODE_CTRL_STAT_MDIX_MODE)
+		phydev->mdix = ETH_TP_MDI_X;
+	else
+		phydev->mdix = ETH_TP_MDI;
+
+	return 0;
+}
+
+static int cbtx_read_status(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = cbtx_mdix_status(phydev);
+	if (ret)
+		return ret;
+
+	return genphy_read_status(phydev);
+}
+
+static int cbtx_mdix_config(struct phy_device *phydev)
+{
+	int ret;
+
+	switch (phydev->mdix_ctrl) {
+	case ETH_TP_MDI_AUTO:
+		return phy_set_bits(phydev, CBTX_MODE_CTRL_STAT,
+				    CBTX_MODE_CTRL_STAT_AUTO_MDIX_EN);
+	case ETH_TP_MDI:
+		ret = phy_clear_bits(phydev, CBTX_MODE_CTRL_STAT,
+				     CBTX_MODE_CTRL_STAT_AUTO_MDIX_EN);
+		if (ret)
+			return ret;
+
+		return phy_clear_bits(phydev, CBTX_MODE_CTRL_STAT,
+				      CBTX_MODE_CTRL_STAT_MDIX_MODE);
+	case ETH_TP_MDI_X:
+		ret = phy_clear_bits(phydev, CBTX_MODE_CTRL_STAT,
+				     CBTX_MODE_CTRL_STAT_AUTO_MDIX_EN);
+		if (ret)
+			return ret;
+
+		return phy_set_bits(phydev, CBTX_MODE_CTRL_STAT,
+				    CBTX_MODE_CTRL_STAT_MDIX_MODE);
+	}
+
+	return 0;
+}
+
+static int cbtx_config_aneg(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = cbtx_mdix_config(phydev);
+	if (ret)
+		return ret;
+
+	return genphy_config_aneg(phydev);
+}
+
+static int cbtx_ack_interrupts(struct phy_device *phydev)
+{
+	return phy_read(phydev, CBTX_IRQ_STAT);
+}
+
+static int cbtx_config_intr(struct phy_device *phydev)
+{
+	int ret;
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		ret = cbtx_ack_interrupts(phydev);
+		if (ret < 0)
+			return ret;
+
+		ret = phy_write(phydev, CBTX_IRQ_ENABLE, CBTX_IRQ_LINK_DOWN |
+				CBTX_IRQ_AN_COMPLETE | CBTX_IRQ_ENERGYON);
+		if (ret)
+			return ret;
+	} else {
+		ret = phy_write(phydev, CBTX_IRQ_ENABLE, 0);
+		if (ret)
+			return ret;
+
+		ret = cbtx_ack_interrupts(phydev);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static irqreturn_t cbtx_handle_interrupt(struct phy_device *phydev)
+{
+	int irq_stat, irq_enabled;
+
+	irq_stat = cbtx_ack_interrupts(phydev);
+	if (irq_stat < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	irq_enabled = phy_read(phydev, CBTX_IRQ_ENABLE);
+	if (irq_enabled < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	if (!(irq_enabled & irq_stat))
+		return IRQ_NONE;
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
+static int cbtx_get_sset_count(struct phy_device *phydev)
+{
+	return 1;
+}
+
+static void cbtx_get_strings(struct phy_device *phydev, u8 *data)
+{
+	ethtool_puts(&data, "100btx_rx_err");
+}
+
+static void cbtx_get_stats(struct phy_device *phydev,
+			   struct ethtool_stats *stats, u64 *data)
+{
+	int ret;
+
+	ret = phy_read(phydev, CBTX_RX_ERR_COUNTER);
+	data[0] = (ret < 0) ? U64_MAX : ret;
+}
+
+static struct phy_driver cbtx_driver[] = {
+	{
+		PHY_ID_MATCH_MODEL(PHY_ID_CBTX_SJA1110),
+		.name			= "NXP CBTX (SJA1110)",
+		/* PHY_BASIC_FEATURES */
+		.soft_reset		= cbtx_soft_reset,
+		.config_init		= cbtx_config_init,
+		.suspend		= genphy_suspend,
+		.resume			= genphy_resume,
+		.config_intr		= cbtx_config_intr,
+		.handle_interrupt	= cbtx_handle_interrupt,
+		.read_status		= cbtx_read_status,
+		.config_aneg		= cbtx_config_aneg,
+		.get_sset_count		= cbtx_get_sset_count,
+		.get_strings		= cbtx_get_strings,
+		.get_stats		= cbtx_get_stats,
+	},
+};
+
+module_phy_driver(cbtx_driver);
+
+static const struct mdio_device_id __maybe_unused cbtx_tbl[] = {
+	{ PHY_ID_MATCH_MODEL(PHY_ID_CBTX_SJA1110) },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(mdio, cbtx_tbl);
+
+MODULE_AUTHOR("Vladimir Oltean <vladimir.oltean@nxp.com>");
+MODULE_DESCRIPTION("NXP CBTX PHY driver");
+MODULE_LICENSE("GPL");