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, 204 insertions, 0 deletions

diff --git a/drivers/hid/hid-pl.c b/drivers/hid/hid-pl.c
new file mode 100644
index 000000000..cae56a6c9
--- /dev/null
+++ b/drivers/hid/hid-pl.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Force feedback support for PantherLord/GreenAsia based devices
+ *
+ *  The devices are distributed under various names and the same USB device ID
+ *  can be used in both adapters and actual game controllers.
+ *
+ *  0810:0001 "Twin USB Joystick"
+ *   - tested with PantherLord USB/PS2 2in1 Adapter
+ *   - contains two reports, one for each port (HID_QUIRK_MULTI_INPUT)
+ *
+ *  0e8f:0003 "GreenAsia Inc.    USB Joystick     "
+ *   - tested with König Gaming gamepad
+ *
+ *  0e8f:0003 "GASIA USB Gamepad"
+ *   - another version of the König gamepad
+ *
+ *  0f30:0111 "Saitek Color Rumble Pad"
+ *
+ *  Copyright (c) 2007, 2009 Anssi Hannula <anssi.hannula@gmail.com>
+ */
+
+/*
+ */
+
+
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/hid.h>
+
+#include "hid-ids.h"
+
+#ifdef CONFIG_PANTHERLORD_FF
+
+struct plff_device {
+	struct hid_report *report;
+	s32 maxval;
+	s32 *strong;
+	s32 *weak;
+};
+
+static int hid_plff_play(struct input_dev *dev, void *data,
+			 struct ff_effect *effect)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+	struct plff_device *plff = data;
+	int left, right;
+
+	left = effect->u.rumble.strong_magnitude;
+	right = effect->u.rumble.weak_magnitude;
+	hid_dbg(dev, "called with 0x%04x 0x%04x", left, right);
+
+	left = left * plff->maxval / 0xffff;
+	right = right * plff->maxval / 0xffff;
+
+	*plff->strong = left;
+	*plff->weak = right;
+	hid_dbg(dev, "running with 0x%02x 0x%02x", left, right);
+	hid_hw_request(hid, plff->report, HID_REQ_SET_REPORT);
+
+	return 0;
+}
+
+static int pl_input_configured(struct hid_device *hid, struct hid_input *hidinput)
+{
+	struct plff_device *plff;
+	struct hid_report *report;
+	struct list_head *report_list =
+			&hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct input_dev *dev = hidinput->input;
+	int error;
+	s32 maxval;
+	s32 *strong;
+	s32 *weak;
+
+	/* The device contains one output report per physical device, all
+	   containing 1 field, which contains 4 ff00.0002 usages and 4 16bit
+	   absolute values.
+
+	   The input reports also contain a field which contains
+	   8 ff00.0001 usages and 8 boolean values. Their meaning is
+	   currently unknown.
+
+	   A version of the 0e8f:0003 exists that has all the values in
+	   separate fields and misses the extra input field, thus resembling
+	   Zeroplus (hid-zpff) devices.
+	*/
+
+	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) {
+		hid_err(hid, "no fields in the report\n");
+		return -ENODEV;
+	}
+
+	maxval = 0x7f;
+	if (report->field[0]->report_count >= 4) {
+		report->field[0]->value[0] = 0x00;
+		report->field[0]->value[1] = 0x00;
+		strong = &report->field[0]->value[2];
+		weak = &report->field[0]->value[3];
+		hid_dbg(hid, "detected single-field device");
+	} else if (report->field[0]->maxusage == 1 &&
+		   report->field[0]->usage[0].hid ==
+			(HID_UP_LED | 0x43) &&
+		   report->maxfield >= 4 &&
+		   report->field[0]->report_count >= 1 &&
+		   report->field[1]->report_count >= 1 &&
+		   report->field[2]->report_count >= 1 &&
+		   report->field[3]->report_count >= 1) {
+		report->field[0]->value[0] = 0x00;
+		report->field[1]->value[0] = 0x00;
+		strong = &report->field[2]->value[0];
+		weak = &report->field[3]->value[0];
+		if (hid->vendor == USB_VENDOR_ID_JESS2)
+			maxval = 0xff;
+		hid_dbg(hid, "detected 4-field device");
+	} else {
+		hid_err(hid, "not enough fields or values\n");
+		return -ENODEV;
+	}
+
+	plff = kzalloc_obj(struct plff_device);
+	if (!plff)
+		return -ENOMEM;
+
+	dev = hidinput->input;
+
+	set_bit(FF_RUMBLE, dev->ffbit);
+
+	error = input_ff_create_memless(dev, plff, hid_plff_play);
+	if (error) {
+		kfree(plff);
+		return error;
+	}
+
+	plff->report = report;
+	plff->strong = strong;
+	plff->weak = weak;
+	plff->maxval = maxval;
+
+	*strong = 0x00;
+	*weak = 0x00;
+	hid_hw_request(hid, plff->report, HID_REQ_SET_REPORT);
+
+	return 0;
+}
+#else
+static inline int pl_input_configured(struct hid_device *hid,
+				      struct hid_input *hidinput)
+{
+	return 0;
+}
+#endif
+
+static int pl_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+
+	if (id->driver_data)
+		hdev->quirks |= HID_QUIRK_MULTI_INPUT;
+
+	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 struct hid_device_id pl_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PSX_ADAPTOR),
+		.driver_data = 1 }, /* Twin USB Joystick */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PCS_ADAPTOR),
+		.driver_data = 1 }, /* Twin USB Joystick */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GREENASIA, 0x0003), },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_JESS2, USB_DEVICE_ID_JESS2_COLOR_RUMBLE_PAD), },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, pl_devices);
+
+static struct hid_driver pl_driver = {
+	.name = "pantherlord",
+	.id_table = pl_devices,
+	.probe = pl_probe,
+	.input_configured = pl_input_configured,
+};
+module_hid_driver(pl_driver);
+
+MODULE_DESCRIPTION("Force feedback support for PantherLord/GreenAsia based devices");
+MODULE_LICENSE("GPL");