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, 101 insertions, 0 deletions

diff --git a/drivers/hid/hid-rapoo.c b/drivers/hid/hid-rapoo.c
new file mode 100644
index 000000000..5c9c396fa
--- /dev/null
+++ b/drivers/hid/hid-rapoo.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm-generic/errno-base.h>
+#include <asm-generic/int-ll64.h>
+#include <linux/bitops.h>
+#include <linux/input.h>
+#include <linux/input-event-codes.h>
+#include <linux/module.h>
+#include <linux/hid.h>
+#include <linux/usb.h>
+
+#include "hid-ids.h"
+
+#define RAPOO_BTN_BACK			0x08
+#define RAPOO_BTN_FORWARD		0x10
+
+static const struct hid_device_id rapoo_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_RAPOO, USB_DEVICE_ID_RAPOO_2_4G_RECEIVER) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, rapoo_devices);
+
+static int rapoo_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+	struct input_dev *input;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		return ret;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "start failed\n");
+		return ret;
+	}
+
+	if (hid_is_usb(hdev)) {
+		struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
+
+		if (intf->cur_altsetting->desc.bInterfaceNumber != 1)
+			return 0;
+	}
+
+	input = devm_input_allocate_device(&hdev->dev);
+	if (!input)
+		return -ENOMEM;
+
+	input->name = "Rapoo 2.4G Wireless Mouse";
+	input->phys = "rapoo/input1";
+	input->id.bustype = hdev->bus;
+	input->id.vendor = hdev->vendor;
+	input->id.product = hdev->product;
+	input->id.version = hdev->version;
+
+	__set_bit(EV_KEY, input->evbit);
+	__set_bit(KEY_BACK, input->keybit);
+	__set_bit(KEY_FORWARD, input->keybit);
+
+	ret = input_register_device(input);
+	if (ret)
+		return ret;
+
+	hid_set_drvdata(hdev, input);
+
+	return ret;
+}
+
+static int rapoo_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data, int size)
+{
+	struct input_dev *input = hid_get_drvdata(hdev);
+
+	if (!input)
+		return 0;
+
+	if (report->id == 1 && size >= 2) {
+		u8 btn = data[1];
+
+		input_report_key(input, KEY_BACK, btn & RAPOO_BTN_BACK);
+		input_report_key(input, KEY_FORWARD, btn & RAPOO_BTN_FORWARD);
+		input_sync(input);
+		return 1;
+	}
+
+	return 0;
+}
+
+static struct hid_driver rapoo_driver = {
+	.name = "hid-rapoo",
+	.id_table = rapoo_devices,
+	.probe = rapoo_probe,
+	.raw_event = rapoo_raw_event,
+};
+
+module_hid_driver(rapoo_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Nguyen Dinh Dang Duong <dangduong31205@gmail.com>");
+MODULE_DESCRIPTION("RAPOO 2.4G Wireless Device Driver");
+