KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed.  Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.

Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical.

Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration")
Cc: stable@vger.kernel.org
Reported-by: Stefan Teodorescu <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 208 insertions, 0 deletions

diff --git a/drivers/hid/hid-saitek.c b/drivers/hid/hid-saitek.c
new file mode 100644
index 000000000..6fe7c087c
--- /dev/null
+++ b/drivers/hid/hid-saitek.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for Saitek devices.
+ *
+ *  PS1000 (USB gamepad):
+ *  Fixes the HID report descriptor by removing a non-existent axis and
+ *  clearing the constant bit on the input reports for buttons and d-pad.
+ *  (This module is based on "hid-ortek".)
+ *  Copyright (c) 2012 Andreas Hübner
+ *
+ *  R.A.T.7, R.A.T.9, M.M.O.7 (USB gaming mice):
+ *  Fixes the mode button which cycles through three constantly pressed
+ *  buttons. All three press events are mapped to one button and the
+ *  missing release event is generated immediately.
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include "hid-ids.h"
+
+#define SAITEK_FIX_PS1000	0x0001
+#define SAITEK_RELEASE_MODE_RAT7	0x0002
+#define SAITEK_RELEASE_MODE_MMO7	0x0004
+
+struct saitek_sc {
+	unsigned long quirks;
+	int mode;
+};
+
+static int saitek_probe(struct hid_device *hdev,
+		const struct hid_device_id *id)
+{
+	unsigned long quirks = id->driver_data;
+	struct saitek_sc *ssc;
+	int ret;
+
+	ssc = devm_kzalloc(&hdev->dev, sizeof(*ssc), GFP_KERNEL);
+	if (ssc == NULL) {
+		hid_err(hdev, "can't alloc saitek descriptor\n");
+		return -ENOMEM;
+	}
+
+	ssc->quirks = quirks;
+	ssc->mode = -1;
+
+	hid_set_drvdata(hdev, ssc);
+
+	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, "hw start failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const __u8 *saitek_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	struct saitek_sc *ssc = hid_get_drvdata(hdev);
+
+	if ((ssc->quirks & SAITEK_FIX_PS1000) && *rsize == 137 &&
+			rdesc[20] == 0x09 && rdesc[21] == 0x33 &&
+			rdesc[94] == 0x81 && rdesc[95] == 0x03 &&
+			rdesc[110] == 0x81 && rdesc[111] == 0x03) {
+
+		hid_info(hdev, "Fixing up Saitek PS1000 report descriptor\n");
+
+		/* convert spurious axis to a "noop" Logical Minimum (0) */
+		rdesc[20] = 0x15;
+		rdesc[21] = 0x00;
+
+		/* clear constant bit on buttons and d-pad */
+		rdesc[95] = 0x02;
+		rdesc[111] = 0x02;
+
+	}
+	return rdesc;
+}
+
+static int saitek_raw_event(struct hid_device *hdev,
+		struct hid_report *report, u8 *raw_data, int size)
+{
+	struct saitek_sc *ssc = hid_get_drvdata(hdev);
+
+	if (ssc->quirks & SAITEK_RELEASE_MODE_RAT7 && size == 7) {
+		/* R.A.T.7 uses bits 13, 14, 15 for the mode */
+		int mode = -1;
+		if (raw_data[1] & 0x01)
+			mode = 0;
+		else if (raw_data[1] & 0x02)
+			mode = 1;
+		else if (raw_data[1] & 0x04)
+			mode = 2;
+
+		/* clear mode bits */
+		raw_data[1] &= ~0x07;
+
+		if (mode != ssc->mode) {
+			hid_dbg(hdev, "entered mode %d\n", mode);
+			if (ssc->mode != -1) {
+				/* use bit 13 as the mode button */
+				raw_data[1] |= 0x04;
+			}
+			ssc->mode = mode;
+		}
+	} else if (ssc->quirks & SAITEK_RELEASE_MODE_MMO7 && size == 8) {
+
+		/* M.M.O.7 uses bits 8, 22, 23 for the mode */
+		int mode = -1;
+		if (raw_data[1] & 0x80)
+			mode = 0;
+		else if (raw_data[2] & 0x01)
+			mode = 1;
+		else if (raw_data[2] & 0x02)
+			mode = 2;
+
+		/* clear mode bits */
+		raw_data[1] &= ~0x80;
+		raw_data[2] &= ~0x03;
+
+		if (mode != ssc->mode) {
+			hid_dbg(hdev, "entered mode %d\n", mode);
+			if (ssc->mode != -1) {
+				/* use bit 8 as the mode button, bits 22
+				 * and 23 do not represent buttons
+				 * according to the HID report descriptor
+				 */
+				raw_data[1] |= 0x80;
+			}
+			ssc->mode = mode;
+		}
+	}
+
+	return 0;
+}
+
+static int saitek_event(struct hid_device *hdev, struct hid_field *field,
+		struct hid_usage *usage, __s32 value)
+{
+	struct saitek_sc *ssc = hid_get_drvdata(hdev);
+	struct input_dev *input = field->hidinput->input;
+
+	if (usage->type == EV_KEY && value &&
+			(((ssc->quirks & SAITEK_RELEASE_MODE_RAT7) &&
+			  usage->code - BTN_MOUSE == 10) ||
+			((ssc->quirks & SAITEK_RELEASE_MODE_MMO7) &&
+			 usage->code - BTN_MOUSE == 15))) {
+
+		input_report_key(input, usage->code, 1);
+
+		/* report missing release event */
+		input_report_key(input, usage->code, 0);
+
+		return 1;
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id saitek_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_PS1000),
+		.driver_data = SAITEK_FIX_PS1000 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MADCATZ, USB_DEVICE_ID_MADCATZ_RAT5),
+		.driver_data = SAITEK_RELEASE_MODE_RAT7 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT7_OLD),
+		.driver_data = SAITEK_RELEASE_MODE_RAT7 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT7),
+		.driver_data = SAITEK_RELEASE_MODE_RAT7 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT7_CONTAGION),
+		.driver_data = SAITEK_RELEASE_MODE_RAT7 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_RAT9),
+		.driver_data = SAITEK_RELEASE_MODE_RAT7 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MADCATZ, USB_DEVICE_ID_MADCATZ_RAT9),
+		.driver_data = SAITEK_RELEASE_MODE_RAT7 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SAITEK, USB_DEVICE_ID_SAITEK_MMO7),
+		.driver_data = SAITEK_RELEASE_MODE_MMO7 },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MADCATZ, USB_DEVICE_ID_MADCATZ_MMO7),
+		.driver_data = SAITEK_RELEASE_MODE_MMO7 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(hid, saitek_devices);
+
+static struct hid_driver saitek_driver = {
+	.name = "saitek",
+	.id_table = saitek_devices,
+	.probe = saitek_probe,
+	.report_fixup = saitek_report_fixup,
+	.raw_event = saitek_raw_event,
+	.event = saitek_event,
+};
+module_hid_driver(saitek_driver);
+
+MODULE_DESCRIPTION("HID driver for Saitek devices.");
+MODULE_LICENSE("GPL");