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, 98 insertions, 0 deletions

diff --git a/drivers/hid/hid-glorious.c b/drivers/hid/hid-glorious.c
new file mode 100644
index 000000000..5bbd81248
--- /dev/null
+++ b/drivers/hid/hid-glorious.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  USB HID driver for Glorious PC Gaming Race
+ *  Glorious Model O, O- and D mice.
+ *
+ *  Copyright (c) 2020 Samuel Čavoj <sammko@sammserver.com>
+ */
+
+/*
+ */
+
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+MODULE_AUTHOR("Samuel Čavoj <sammko@sammserver.com>");
+MODULE_DESCRIPTION("HID driver for Glorious PC Gaming Race mice");
+
+/*
+ * Glorious Model O and O- specify the const flag in the consumer input
+ * report descriptor, which leads to inputs being ignored. Fix this
+ * by patching the descriptor.
+ *
+ * Glorious Model I incorrectly specifes the Usage Minimum for its
+ * keyboard HID report, causing keycodes to be misinterpreted.
+ * Fix this by setting Usage Minimum to 0 in that report.
+ */
+static const __u8 *glorious_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize == 213 &&
+		rdesc[84] == 129 && rdesc[112] == 129 && rdesc[140] == 129 &&
+		rdesc[85] == 3   && rdesc[113] == 3   && rdesc[141] == 3) {
+		hid_info(hdev, "patching Glorious Model O consumer control report descriptor\n");
+		rdesc[85] = rdesc[113] = rdesc[141] = \
+			HID_MAIN_ITEM_VARIABLE | HID_MAIN_ITEM_RELATIVE;
+	}
+	if (*rsize == 156 && rdesc[41] == 1) {
+		hid_info(hdev, "patching Glorious Model I keyboard report descriptor\n");
+		rdesc[41] = 0;
+	}
+	return rdesc;
+}
+
+static void glorious_update_name(struct hid_device *hdev)
+{
+	const char *model = "Device";
+
+	switch (hdev->product) {
+	case USB_DEVICE_ID_GLORIOUS_MODEL_O:
+		model = "Model O"; break;
+	case USB_DEVICE_ID_GLORIOUS_MODEL_D:
+		model = "Model D"; break;
+	case USB_DEVICE_ID_GLORIOUS_MODEL_I:
+		model = "Model I"; break;
+	}
+
+	snprintf(hdev->name, sizeof(hdev->name), "%s %s", "Glorious", model);
+}
+
+static int glorious_probe(struct hid_device *hdev,
+		const struct hid_device_id *id)
+{
+	int ret;
+
+	hdev->quirks |= HID_QUIRK_INPUT_PER_APP;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	glorious_update_name(hdev);
+
+	return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+}
+
+static const struct hid_device_id glorious_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SINOWEALTH,
+		USB_DEVICE_ID_GLORIOUS_MODEL_O) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SINOWEALTH,
+		USB_DEVICE_ID_GLORIOUS_MODEL_D) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LAVIEW,
+		USB_DEVICE_ID_GLORIOUS_MODEL_I) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, glorious_devices);
+
+static struct hid_driver glorious_driver = {
+	.name = "glorious",
+	.id_table = glorious_devices,
+	.probe = glorious_probe,
+	.report_fixup = glorious_report_fixup
+};
+
+module_hid_driver(glorious_driver);
+
+MODULE_LICENSE("GPL");