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, 246 insertions, 0 deletions

diff --git a/drivers/hid/hid-cmedia.c b/drivers/hid/hid-cmedia.c
new file mode 100644
index 000000000..7b3dd4197
--- /dev/null
+++ b/drivers/hid/hid-cmedia.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID driver for CMedia CM6533 audio jack controls
+ * and HS100B mute buttons
+ *
+ * Copyright (C) 2015 Ben Chen <ben_chen@bizlinktech.com>
+ * Copyright (C) 2021 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include "hid-ids.h"
+
+MODULE_AUTHOR("Ben Chen");
+MODULE_AUTHOR("Thomas Weißschuh");
+MODULE_DESCRIPTION("CM6533 HID jack controls and HS100B mute button");
+MODULE_LICENSE("GPL");
+
+#define CM6533_JD_TYPE_COUNT      1
+#define CM6533_JD_RAWEV_LEN	 16
+#define CM6533_JD_SFX_OFFSET	  8
+
+#define HS100B_RDESC_ORIG_SIZE   60
+
+/* Fixed report descriptor of HS-100B audio chip
+ * Bit 4 is an abolute Microphone mute usage instead of being unassigned.
+ */
+static const __u8 hs100b_rdesc_fixed[] = {
+	0x05, 0x0C,         /*  Usage Page (Consumer),          */
+	0x09, 0x01,         /*  Usage (Consumer Control),       */
+	0xA1, 0x01,         /*  Collection (Application),       */
+	0x15, 0x00,         /*      Logical Minimum (0),        */
+	0x25, 0x01,         /*      Logical Maximum (1),        */
+	0x09, 0xE9,         /*      Usage (Volume Inc),         */
+	0x09, 0xEA,         /*      Usage (Volume Dec),         */
+	0x75, 0x01,         /*      Report Size (1),            */
+	0x95, 0x02,         /*      Report Count (2),           */
+	0x81, 0x02,         /*      Input (Variable),           */
+	0x09, 0xE2,         /*      Usage (Mute),               */
+	0x95, 0x01,         /*      Report Count (1),           */
+	0x81, 0x06,         /*      Input (Variable, Relative), */
+	0x05, 0x0B,         /*      Usage Page (Telephony),     */
+	0x09, 0x2F,         /*      Usage (2Fh),                */
+	0x81, 0x02,         /*      Input (Variable),           */
+	0x09, 0x20,         /*      Usage (20h),                */
+	0x81, 0x06,         /*      Input (Variable, Relative), */
+	0x05, 0x0C,         /*      Usage Page (Consumer),      */
+	0x09, 0x00,         /*      Usage (00h),                */
+	0x95, 0x03,         /*      Report Count (3),           */
+	0x81, 0x02,         /*      Input (Variable),           */
+	0x26, 0xFF, 0x00,   /*      Logical Maximum (255),      */
+	0x09, 0x00,         /*      Usage (00h),                */
+	0x75, 0x08,         /*      Report Size (8),            */
+	0x95, 0x03,         /*      Report Count (3),           */
+	0x81, 0x02,         /*      Input (Variable),           */
+	0x09, 0x00,         /*      Usage (00h),                */
+	0x95, 0x04,         /*      Report Count (4),           */
+	0x91, 0x02,         /*      Output (Variable),          */
+	0xC0                /*  End Collection                  */
+};
+
+/*
+*
+*CM6533 audio jack HID raw events:
+*
+*Plug in:
+*01000600 002083xx 080008c0 10000000
+*about 3 seconds later...
+*01000a00 002083xx 08000380 10000000
+*01000600 002083xx 08000380 10000000
+*
+*Plug out:
+*01000400 002083xx 080008c0 x0000000
+*/
+
+static const u8 ji_sfx[] = { 0x08, 0x00, 0x08, 0xc0 };
+static const u8 ji_in[]  = { 0x01, 0x00, 0x06, 0x00 };
+static const u8 ji_out[] = { 0x01, 0x00, 0x04, 0x00 };
+
+static int jack_switch_types[CM6533_JD_TYPE_COUNT] = {
+	SW_HEADPHONE_INSERT,
+};
+
+struct cmhid {
+	struct input_dev *input_dev;
+	struct hid_device *hid;
+	unsigned short switch_map[CM6533_JD_TYPE_COUNT];
+};
+
+static void hp_ev(struct hid_device *hid, struct cmhid *cm, int value)
+{
+	input_report_switch(cm->input_dev, SW_HEADPHONE_INSERT, value);
+	input_sync(cm->input_dev);
+}
+
+static int cmhid_raw_event(struct hid_device *hid, struct hid_report *report,
+	 u8 *data, int len)
+{
+	struct cmhid *cm = hid_get_drvdata(hid);
+
+	if (len != CM6533_JD_RAWEV_LEN || !(hid->claimed & HID_CLAIMED_INPUT))
+		goto out;
+	if (memcmp(data+CM6533_JD_SFX_OFFSET, ji_sfx, sizeof(ji_sfx)))
+		goto out;
+
+	if (!memcmp(data, ji_out, sizeof(ji_out))) {
+		hp_ev(hid, cm, 0);
+		goto out;
+	}
+	if (!memcmp(data, ji_in, sizeof(ji_in))) {
+		hp_ev(hid, cm, 1);
+		goto out;
+	}
+
+out:
+	return 0;
+}
+
+static int cmhid_input_configured(struct hid_device *hid,
+		struct hid_input *hidinput)
+{
+	struct input_dev *input_dev = hidinput->input;
+	struct cmhid *cm = hid_get_drvdata(hid);
+	int i;
+
+	cm->input_dev = input_dev;
+	memcpy(cm->switch_map, jack_switch_types, sizeof(cm->switch_map));
+	input_dev->evbit[0] = BIT(EV_SW);
+	for (i = 0; i < CM6533_JD_TYPE_COUNT; i++)
+		input_set_capability(cm->input_dev,
+				EV_SW, jack_switch_types[i]);
+	return 0;
+}
+
+static int cmhid_input_mapping(struct hid_device *hid,
+		struct hid_input *hi, struct hid_field *field,
+		struct hid_usage *usage, unsigned long **bit, int *max)
+{
+	return -1;
+}
+
+static int cmhid_probe(struct hid_device *hid, const struct hid_device_id *id)
+{
+	int ret;
+	struct cmhid *cm;
+
+	cm = kzalloc_obj(struct cmhid);
+	if (!cm) {
+		ret = -ENOMEM;
+		goto allocfail;
+	}
+
+	cm->hid = hid;
+
+	hid->quirks |= HID_QUIRK_HIDINPUT_FORCE;
+	hid_set_drvdata(hid, cm);
+
+	ret = hid_parse(hid);
+	if (ret) {
+		hid_err(hid, "parse failed\n");
+		goto fail;
+	}
+
+	ret = hid_hw_start(hid, HID_CONNECT_DEFAULT | HID_CONNECT_HIDDEV_FORCE);
+	if (ret) {
+		hid_err(hid, "hw start failed\n");
+		goto fail;
+	}
+
+	return 0;
+fail:
+	kfree(cm);
+allocfail:
+	return ret;
+}
+
+static void cmhid_remove(struct hid_device *hid)
+{
+	struct cmhid *cm = hid_get_drvdata(hid);
+
+	hid_hw_stop(hid);
+	kfree(cm);
+}
+
+static const struct hid_device_id cmhid_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CMEDIA, USB_DEVICE_ID_CM6533) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, cmhid_devices);
+
+static struct hid_driver cmhid_driver = {
+	.name = "cm6533_jd",
+	.id_table = cmhid_devices,
+	.raw_event = cmhid_raw_event,
+	.input_configured = cmhid_input_configured,
+	.probe = cmhid_probe,
+	.remove = cmhid_remove,
+	.input_mapping = cmhid_input_mapping,
+};
+
+static const __u8 *cmhid_hs100b_report_fixup(struct hid_device *hid, __u8 *rdesc,
+				       unsigned int *rsize)
+{
+	if (*rsize == HS100B_RDESC_ORIG_SIZE) {
+		hid_info(hid, "Fixing CMedia HS-100B report descriptor\n");
+		*rsize = sizeof(hs100b_rdesc_fixed);
+		return hs100b_rdesc_fixed;
+	}
+	return rdesc;
+}
+
+static const struct hid_device_id cmhid_hs100b_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CMEDIA, USB_DEVICE_ID_CMEDIA_HS100B) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, cmhid_hs100b_devices);
+
+static struct hid_driver cmhid_hs100b_driver = {
+	.name = "cmedia_hs100b",
+	.id_table = cmhid_hs100b_devices,
+	.report_fixup = cmhid_hs100b_report_fixup,
+};
+
+static int cmedia_init(void)
+{
+	int ret;
+
+	ret = hid_register_driver(&cmhid_driver);
+	if (ret)
+		return ret;
+
+	ret = hid_register_driver(&cmhid_hs100b_driver);
+	if (ret)
+		hid_unregister_driver(&cmhid_driver);
+
+	return ret;
+}
+module_init(cmedia_init);
+
+static void cmedia_exit(void)
+{
+		hid_unregister_driver(&cmhid_driver);
+		hid_unregister_driver(&cmhid_hs100b_driver);
+}
+module_exit(cmedia_exit);