arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted

__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.
PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in
HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host
traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The
kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU
driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a
write from EL0 reaches the trap and takes the host down without a panic
message.

Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already
does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9
bits.

Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 117 insertions, 0 deletions

diff --git a/drivers/hid/hid-hyperx.c b/drivers/hid/hid-hyperx.c
new file mode 100644
index 000000000..18d2dc24c
--- /dev/null
+++ b/drivers/hid/hid-hyperx.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for the HyperX QuadCast 2 microphone
+ *
+ *  The tap-to-mute button is handled entirely in the device firmware: it gates
+ *  the audio internally and does not send the Telephony "Phone Mute" usage its
+ *  own report descriptor advertises.  The resulting mute state is only reported
+ *  through a vendor-defined collection, which hid-input cannot map, so the
+ *  button is invisible to userspace.
+ *
+ *  Copyright (c) 2026 Benjamin Blume <benjaminblume@posteo.de>
+ */
+
+#include <linux/hid.h>
+#include <linux/input.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+#define HYPERX_QC2_REPORT_ID	0x77
+#define HYPERX_QC2_EVENT_MUTE	0x06
+#define HYPERX_QC2_MUTE_LEN	3
+
+struct hyperx_drvdata {
+	struct input_dev *input;
+	bool muted;
+	bool have_state;
+};
+
+static int hyperx_input_configured(struct hid_device *hdev,
+				   struct hid_input *hi)
+{
+	struct hyperx_drvdata *drvdata = hid_get_drvdata(hdev);
+
+	/*
+	 * The device exposes several application collections.  Prefer the
+	 * telephony one, which already advertises KEY_MICMUTE, and fall back
+	 * to the first collection otherwise.
+	 */
+	if (!drvdata->input || test_bit(KEY_MICMUTE, hi->input->keybit)) {
+		drvdata->input = hi->input;
+		input_set_capability(drvdata->input, EV_KEY, KEY_MICMUTE);
+	}
+
+	return 0;
+}
+
+static int hyperx_raw_event(struct hid_device *hdev, struct hid_report *report,
+			    u8 *data, int size)
+{
+	struct hyperx_drvdata *drvdata = hid_get_drvdata(hdev);
+	bool muted;
+
+	if (!(hdev->claimed & HID_CLAIMED_INPUT) || !drvdata->input)
+		return 0;
+
+	if (size < HYPERX_QC2_MUTE_LEN || data[0] != HYPERX_QC2_REPORT_ID ||
+	    data[1] != HYPERX_QC2_EVENT_MUTE)
+		return 0;
+
+	muted = data[2];
+	if (drvdata->have_state && muted == drvdata->muted)
+		return 0;
+
+	drvdata->muted = muted;
+	drvdata->have_state = true;
+
+	/*
+	 * The device reports the resulting absolute state, while KEY_MICMUTE is
+	 * a momentary key that userspace acts on as a toggle.  Emit one
+	 * keypress per state change.
+	 */
+	input_report_key(drvdata->input, KEY_MICMUTE, 1);
+	input_sync(drvdata->input);
+	input_report_key(drvdata->input, KEY_MICMUTE, 0);
+	input_sync(drvdata->input);
+
+	return 0;
+}
+
+static int hyperx_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct hyperx_drvdata *drvdata;
+	int ret;
+
+	drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	hid_set_drvdata(hdev, drvdata);
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+}
+
+static const struct hid_device_id hyperx_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_HP,
+			 USB_PRODUCT_ID_HP_HYPERX_QUADCAST_2) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, hyperx_devices);
+
+static struct hid_driver hyperx_driver = {
+	.name			= "hyperx",
+	.id_table		= hyperx_devices,
+	.probe			= hyperx_probe,
+	.input_configured	= hyperx_input_configured,
+	.raw_event		= hyperx_raw_event,
+};
+module_hid_driver(hyperx_driver);
+
+MODULE_DESCRIPTION("HID driver for the HyperX QuadCast 2 microphone");
+MODULE_AUTHOR("Benjamin Blume <benjaminblume@posteo.de>");
+MODULE_LICENSE("GPL");