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, 60 insertions, 0 deletions

diff --git a/drivers/hid/hid-xinmo.c b/drivers/hid/hid-xinmo.c
new file mode 100644
index 000000000..66b8bfb6e
--- /dev/null
+++ b/drivers/hid/hid-xinmo.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for Xin-Mo devices, currently only the Dual Arcade controller.
+ *  Fixes the negative axis event values (the devices sends -2) to match the
+ *  logical axis minimum of the HID report descriptor (the report announces
+ *  -1). It is needed because hid-input discards out of bounds values.
+ *  (This module is based on "hid-saitek" and "hid-lg".)
+ *
+ *  Copyright (c) 2013 Olivier Scherler
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include "hid-ids.h"
+
+/*
+ * Fix negative events that are out of bounds.
+ */
+static int xinmo_event(struct hid_device *hdev, struct hid_field *field,
+		struct hid_usage *usage, __s32 value)
+{
+	switch (usage->code) {
+	case ABS_X:
+	case ABS_Y:
+	case ABS_Z:
+	case ABS_RX:
+		if (value < -1) {
+			input_event(field->hidinput->input, usage->type,
+				usage->code, -1);
+			return 1;
+		}
+		break;
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id xinmo_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_XIN_MO, USB_DEVICE_ID_XIN_MO_DUAL_ARCADE) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_XIN_MO, USB_DEVICE_ID_THT_2P_ARCADE) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(hid, xinmo_devices);
+
+static struct hid_driver xinmo_driver = {
+	.name = "xinmo",
+	.id_table = xinmo_devices,
+	.event = xinmo_event
+};
+
+module_hid_driver(xinmo_driver);
+MODULE_DESCRIPTION("HID driver for Xin-Mo devices");
+MODULE_LICENSE("GPL");