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, 55 insertions, 0 deletions

diff --git a/drivers/hid/hid-ortek.c b/drivers/hid/hid-ortek.c
new file mode 100644
index 000000000..f27297269
--- /dev/null
+++ b/drivers/hid/hid-ortek.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for various devices which are apparently based on the same chipset
+ *  from certain vendor which produces chips that contain wrong LogicalMaximum
+ *  value in their HID report descriptor. Currently supported devices are:
+ *
+ *    Ortek PKB-1700
+ *    Ortek WKB-2000
+ *    iHome IMAC-A210S
+ *    Skycable wireless presenter
+ *
+ *  Copyright (c) 2010 Johnathon Harris <jmharris@gmail.com>
+ *  Copyright (c) 2011 Jiri Kosina
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+static const __u8 *ortek_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize >= 56 && rdesc[54] == 0x25 && rdesc[55] == 0x01) {
+		hid_info(hdev, "Fixing up logical maximum in report descriptor (Ortek)\n");
+		rdesc[55] = 0x92;
+	} else if (*rsize >= 54 && rdesc[52] == 0x25 && rdesc[53] == 0x01) {
+		hid_info(hdev, "Fixing up logical maximum in report descriptor (Skycable)\n");
+		rdesc[53] = 0x65;
+	}
+	return rdesc;
+}
+
+static const struct hid_device_id ortek_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_PKB1700) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_WKB2000) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ORTEK, USB_DEVICE_ID_ORTEK_IHOME_IMAC_A210S) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SKYCABLE, USB_DEVICE_ID_SKYCABLE_WIRELESS_PRESENTER) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ortek_devices);
+
+static struct hid_driver ortek_driver = {
+	.name = "ortek",
+	.id_table = ortek_devices,
+	.report_fixup = ortek_report_fixup
+};
+module_hid_driver(ortek_driver);
+
+MODULE_DESCRIPTION("HID driver for Ortek PKB-1700/WKB-2000/Skycable wireless keyboard and mouse trackpad");
+MODULE_LICENSE("GPL");