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, 147 insertions, 0 deletions

diff --git a/drivers/hid/hid-mf.c b/drivers/hid/hid-mf.c
new file mode 100644
index 000000000..136e8b41d
--- /dev/null
+++ b/drivers/hid/hid-mf.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Force feedback support for Mayflash game controller adapters.
+ *
+ * These devices are manufactured by Mayflash but identify themselves
+ * using the vendor ID of DragonRise Inc.
+ *
+ * Tested with:
+ * 0079:1801 "DragonRise Inc. Mayflash PS3 Game Controller Adapter"
+ * 0079:1803 "DragonRise Inc. Mayflash Wireless Sensor DolphinBar"
+ * 0079:1843 "DragonRise Inc. Mayflash GameCube Game Controller Adapter"
+ * 0079:1844 "DragonRise Inc. Mayflash GameCube Game Controller Adapter (v04)"
+ *
+ * The following adapters probably work too, but need to be tested:
+ * 0079:1800 "DragonRise Inc. Mayflash WIIU Game Controller Adapter"
+ *
+ * Copyright (c) 2016-2017 Marcel Hasler <mahasler@gmail.com>
+ */
+
+/*
+ */
+
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+struct mf_device {
+	struct hid_report *report;
+};
+
+static int mf_play(struct input_dev *dev, void *data, struct ff_effect *effect)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+	struct mf_device *mf = data;
+	int strong, weak;
+
+	strong = effect->u.rumble.strong_magnitude;
+	weak = effect->u.rumble.weak_magnitude;
+
+	dbg_hid("Called with 0x%04x 0x%04x.\n", strong, weak);
+
+	strong = strong * 0xff / 0xffff;
+	weak = weak * 0xff / 0xffff;
+
+	dbg_hid("Running with 0x%02x 0x%02x.\n", strong, weak);
+
+	mf->report->field[0]->value[0] = weak;
+	mf->report->field[0]->value[1] = strong;
+	hid_hw_request(hid, mf->report, HID_REQ_SET_REPORT);
+
+	return 0;
+}
+
+static int mf_input_configured(struct hid_device *hid, struct hid_input *hidinput)
+{
+	struct mf_device *mf;
+	struct list_head *report_list =
+			&hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct hid_report *report;
+	struct input_dev *dev = hidinput->input;
+	int error;
+
+	if (!list_is_first(&hidinput->list, &hid->inputs))
+		return 0;
+
+	report = list_first_entry_or_null(report_list, struct hid_report, list);
+	if (!report) {
+		hid_err(hid, "no output reports found\n");
+		return -ENODEV;
+	}
+
+	if (report->maxfield < 1 || report->field[0]->report_count < 2) {
+		hid_err(hid, "Invalid report, this should never happen!\n");
+		return -ENODEV;
+	}
+
+	mf = kzalloc_obj(struct mf_device);
+	if (!mf)
+		return -ENOMEM;
+
+	mf->report = report;
+	set_bit(FF_RUMBLE, dev->ffbit);
+
+	error = input_ff_create_memless(dev, mf, mf_play);
+	if (error) {
+		kfree(mf);
+		return error;
+	}
+
+	mf->report->field[0]->value[0] = 0x00;
+	mf->report->field[0]->value[1] = 0x00;
+	hid_hw_request(hid, mf->report, HID_REQ_SET_REPORT);
+
+	return 0;
+}
+
+static int mf_probe(struct hid_device *hid, const struct hid_device_id *id)
+{
+	int error;
+
+	dev_dbg(&hid->dev, "Mayflash HID hardware probe...\n");
+
+	/* Apply quirks as needed */
+	hid->quirks |= id->driver_data;
+
+	error = hid_parse(hid);
+	if (error) {
+		hid_err(hid, "HID parse failed.\n");
+		return error;
+	}
+
+	error = hid_hw_start(hid, HID_CONNECT_DEFAULT);
+	if (error) {
+		hid_err(hid, "HID hw start failed\n");
+		return error;
+	}
+
+	return 0;
+}
+static const struct hid_device_id mf_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, USB_DEVICE_ID_DRAGONRISE_PS3),
+		.driver_data = HID_QUIRK_MULTI_INPUT },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, USB_DEVICE_ID_DRAGONRISE_DOLPHINBAR),
+		.driver_data = HID_QUIRK_MULTI_INPUT },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, USB_DEVICE_ID_DRAGONRISE_GAMECUBE1),
+		.driver_data = HID_QUIRK_MULTI_INPUT },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, USB_DEVICE_ID_DRAGONRISE_GAMECUBE2),
+		.driver_data = 0 }, /* No quirk required */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DRAGONRISE, USB_DEVICE_ID_DRAGONRISE_GAMECUBE3),
+		.driver_data = HID_QUIRK_MULTI_INPUT },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, mf_devices);
+
+static struct hid_driver mf_driver = {
+	.name = "hid_mf",
+	.id_table = mf_devices,
+	.probe = mf_probe,
+	.input_configured = mf_input_configured,
+};
+module_hid_driver(mf_driver);
+
+MODULE_DESCRIPTION("Force feedback support for Mayflash game controller adapters.");
+MODULE_LICENSE("GPL");