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, 129 insertions, 0 deletions

diff --git a/drivers/hid/hid-haptic.h b/drivers/hid/hid-haptic.h
new file mode 100644
index 000000000..6332991a7
--- /dev/null
+++ b/drivers/hid/hid-haptic.h
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  HID Haptic support for Linux
+ *
+ *  Copyright (c) 2021 Angela Czubak <acz@semihalf.com>
+ */
+
+#include <linux/hid.h>
+
+#define HID_HAPTIC_ORDINAL_WAVEFORMNONE 1
+#define HID_HAPTIC_ORDINAL_WAVEFORMSTOP 2
+
+#define HID_HAPTIC_MODE_DEVICE 0
+#define HID_HAPTIC_MODE_HOST 1
+
+struct hid_haptic_effect {
+	u8 *report_buf;
+	struct input_dev *input_dev;
+	struct work_struct work;
+	struct list_head control;
+	struct mutex control_mutex;
+};
+
+struct hid_haptic_effect_node {
+	struct list_head node;
+	struct file *file;
+};
+
+struct hid_haptic_device {
+	struct input_dev *input_dev;
+	struct hid_device *hdev;
+	struct hid_report *auto_trigger_report;
+	struct mutex auto_trigger_mutex;
+	struct workqueue_struct *wq;
+	struct hid_report *manual_trigger_report;
+	struct mutex manual_trigger_mutex;
+	size_t manual_trigger_report_len;
+	int pressed_state;
+	s32 pressure_sum;
+	s32 force_logical_minimum;
+	s32 force_physical_minimum;
+	s32 force_resolution;
+	u32 mode;
+	u32 default_auto_trigger;
+	u32 vendor_page;
+	u32 vendor_id;
+	u32 max_waveform_id;
+	u32 max_duration_id;
+	u16 *hid_usage_map;
+	u32 *duration_map;
+	u16 press_ordinal;
+	u16 release_ordinal;
+	struct hid_haptic_effect *effect;
+	struct hid_haptic_effect stop_effect;
+};
+
+#if IS_ENABLED(CONFIG_HID_HAPTIC)
+void hid_haptic_feature_mapping(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_field *field, struct hid_usage
+				*usage);
+bool hid_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
+				    struct hid_input *hi, struct hid_field *field);
+int hid_haptic_input_mapping(struct hid_device *hdev,
+			     struct hid_haptic_device *haptic,
+			     struct hid_input *hi,
+			     struct hid_field *field, struct hid_usage *usage,
+			     unsigned long **bit, int *max);
+int hid_haptic_input_configured(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_input *hi);
+int hid_haptic_init(struct hid_device *hdev, struct hid_haptic_device *haptic,
+		    struct input_dev *dev);
+void hid_haptic_handle_press_release(struct hid_haptic_device *haptic);
+void hid_haptic_pressure_reset(struct hid_haptic_device *haptic);
+void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
+				  __s32 pressure);
+#else
+static inline
+void hid_haptic_feature_mapping(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_field *field, struct hid_usage
+				*usage)
+{}
+static inline
+bool hid_haptic_check_pressure_unit(struct hid_haptic_device *haptic,
+				    struct hid_input *hi, struct hid_field *field)
+{
+	return false;
+}
+static inline
+int hid_haptic_input_mapping(struct hid_device *hdev,
+			     struct hid_haptic_device *haptic,
+			     struct hid_input *hi,
+			     struct hid_field *field, struct hid_usage *usage,
+			     unsigned long **bit, int *max)
+{
+	return 0;
+}
+static inline
+int hid_haptic_input_configured(struct hid_device *hdev,
+				struct hid_haptic_device *haptic,
+				struct hid_input *hi)
+{
+	return 0;
+}
+static inline
+void hid_haptic_reset(struct hid_device *hdev, struct hid_haptic_device *haptic)
+{}
+static inline
+int hid_haptic_init(struct hid_device *hdev, struct hid_haptic_device *haptic,
+		    struct input_dev *dev)
+{
+	return 0;
+}
+static inline
+void hid_haptic_handle_press_release(struct hid_haptic_device *haptic) {}
+static inline
+bool hid_haptic_handle_input(struct hid_haptic_device *haptic)
+{
+	return false;
+}
+static inline
+void hid_haptic_pressure_reset(struct hid_haptic_device *haptic) {}
+static inline
+void hid_haptic_pressure_increase(struct hid_haptic_device *haptic,
+				  __s32 pressure)
+{}
+#endif