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, 135 insertions, 0 deletions

diff --git a/drivers/hid/hid-twinhan.c b/drivers/hid/hid-twinhan.c
new file mode 100644
index 000000000..0ef519408
--- /dev/null
+++ b/drivers/hid/hid-twinhan.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID driver for TwinHan IR remote control
+ *
+ * Based on hid-gyration.c
+ *
+ * Copyright (c) 2009 Bruno Prémont <bonbons@linux-vserver.org>
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+/*	Remote control key layout + listing:
+ *
+ * 	Full Screen                              Power
+ *	KEY_SCREEN                          KEY_POWER2
+ *
+ *	1                     2                      3
+ *	KEY_NUMERIC_1   KEY_NUMERIC_2    KEY_NUMERIC_3
+ *
+ *	4                     5                      6
+ *	KEY_NUMERIC_4   KEY_NUMERIC_5    KEY_NUMERIC_6
+ *
+ *	7                     8                      9
+ *	KEY_NUMERIC_7   KEY_NUMERIC_8    KEY_NUMERIC_9
+ *
+ *	REC                   0               Favorite
+ *	KEY_RECORD      KEY_NUMERIC_0    KEY_FAVORITES
+ *
+ *	Rewind                                 Forward
+ *	KEY_REWIND           CH+           KEY_FORWARD
+ *	               KEY_CHANNELUP
+ *
+ *	VOL-                  >                   VOL+
+ *	KEY_VOLUMEDOWN    KEY_PLAY        KEY_VOLUMEUP
+ *
+ *	                     CH-
+ *	              KEY_CHANNELDOWN
+ *	Recall                                    Stop
+ *	KEY_RESTART                           KEY_STOP
+ *
+ *	Timeshift/Pause     Mute                Cancel
+ *	KEY_PAUSE         KEY_MUTE          KEY_CANCEL
+ *
+ *	Capture            Preview                 EPG
+ *	KEY_PRINT        KEY_PROGRAM           KEY_EPG
+ *
+ *	Record List          Tab              Teletext
+ *	KEY_LIST            KEY_TAB           KEY_TEXT
+ */
+
+#define th_map_key_clear(c)	hid_map_usage_clear(hi, usage, bit, max, \
+					EV_KEY, (c))
+static int twinhan_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_KEYBOARD)
+		return 0;
+
+	switch (usage->hid & HID_USAGE) {
+	/* Map all keys from Twinhan Remote */
+	case 0x004: th_map_key_clear(KEY_TEXT);         break;
+	case 0x006: th_map_key_clear(KEY_RESTART);      break;
+	case 0x008: th_map_key_clear(KEY_EPG);          break;
+	case 0x00c: th_map_key_clear(KEY_REWIND);       break;
+	case 0x00e: th_map_key_clear(KEY_PROGRAM);      break;
+	case 0x00f: th_map_key_clear(KEY_LIST);         break;
+	case 0x010: th_map_key_clear(KEY_MUTE);         break;
+	case 0x011: th_map_key_clear(KEY_FORWARD);      break;
+	case 0x013: th_map_key_clear(KEY_PRINT);        break;
+	case 0x017: th_map_key_clear(KEY_PAUSE);        break;
+	case 0x019: th_map_key_clear(KEY_FAVORITES);    break;
+	case 0x01d: th_map_key_clear(KEY_SCREEN);       break;
+	case 0x01e: th_map_key_clear(KEY_NUMERIC_1);    break;
+	case 0x01f: th_map_key_clear(KEY_NUMERIC_2);    break;
+	case 0x020: th_map_key_clear(KEY_NUMERIC_3);    break;
+	case 0x021: th_map_key_clear(KEY_NUMERIC_4);    break;
+	case 0x022: th_map_key_clear(KEY_NUMERIC_5);    break;
+	case 0x023: th_map_key_clear(KEY_NUMERIC_6);    break;
+	case 0x024: th_map_key_clear(KEY_NUMERIC_7);    break;
+	case 0x025: th_map_key_clear(KEY_NUMERIC_8);    break;
+	case 0x026: th_map_key_clear(KEY_NUMERIC_9);    break;
+	case 0x027: th_map_key_clear(KEY_NUMERIC_0);    break;
+	case 0x028: th_map_key_clear(KEY_PLAY);         break;
+	case 0x029: th_map_key_clear(KEY_CANCEL);       break;
+	case 0x02b: th_map_key_clear(KEY_TAB);          break;
+	/* Power       = 0x0e0 + 0x0e1 + 0x0e2 + 0x03f */
+	case 0x03f: th_map_key_clear(KEY_POWER2);       break;
+	case 0x04a: th_map_key_clear(KEY_RECORD);       break;
+	case 0x04b: th_map_key_clear(KEY_CHANNELUP);    break;
+	case 0x04d: th_map_key_clear(KEY_STOP);         break;
+	case 0x04e: th_map_key_clear(KEY_CHANNELDOWN);  break;
+	/* Volume down = 0x0e1 + 0x051                 */
+	case 0x051: th_map_key_clear(KEY_VOLUMEDOWN);   break;
+	/* Volume up   = 0x0e1 + 0x052                 */
+	case 0x052: th_map_key_clear(KEY_VOLUMEUP);     break;
+	/* Kill the extra keys used for multi-key "power" and "volume" keys
+	 * as well as continuously to release CTRL,ALT,META,... keys */
+	case 0x0e0:
+	case 0x0e1:
+	case 0x0e2:
+	case 0x0e3:
+	case 0x0e4:
+	case 0x0e5:
+	case 0x0e6:
+	case 0x0e7:
+	default:
+		return -1;
+	}
+	return 1;
+}
+
+static const struct hid_device_id twinhan_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_TWINHAN, USB_DEVICE_ID_TWINHAN_IR_REMOTE) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, twinhan_devices);
+
+static struct hid_driver twinhan_driver = {
+	.name = "twinhan",
+	.id_table = twinhan_devices,
+	.input_mapping = twinhan_input_mapping,
+};
+module_hid_driver(twinhan_driver);
+
+MODULE_DESCRIPTION("HID driver for TwinHan IR remote control");
+MODULE_LICENSE("GPL");