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, 72 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-client-probes.h b/sound/soc/sof/sof-client-probes.h
new file mode 100644
index 000000000..47d0582b8
--- /dev/null
+++ b/sound/soc/sof/sof-client-probes.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __SOF_CLIENT_PROBES_H
+#define __SOF_CLIENT_PROBES_H
+
+struct snd_compr_stream;
+struct snd_compr_tstamp64;
+struct snd_compr_params;
+struct sof_client_dev;
+struct snd_soc_dai;
+
+/*
+ * Callbacks used on platforms where the control for audio is split between
+ * DSP and host, like HDA.
+ */
+struct sof_probes_host_ops {
+	int (*startup)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+		       struct snd_soc_dai *dai, u32 *stream_id);
+	int (*shutdown)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+			struct snd_soc_dai *dai);
+	int (*set_params)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+			  struct snd_compr_params *params,
+			  struct snd_soc_dai *dai);
+	int (*trigger)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+		       int cmd, struct snd_soc_dai *dai);
+	int (*pointer)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream,
+		       struct snd_compr_tstamp64 *tstamp,
+		       struct snd_soc_dai *dai);
+};
+
+struct sof_probe_point_desc {
+	unsigned int buffer_id;
+	unsigned int purpose;
+	unsigned int stream_tag;
+} __packed;
+
+enum sof_probe_info_type {
+	PROBES_INFO_ACTIVE_PROBES,
+	PROBES_INFO_AVAILABE_PROBES,
+};
+
+struct sof_probes_ipc_ops {
+	int (*init)(struct sof_client_dev *cdev, u32 stream_tag,
+		    size_t buffer_size);
+	int (*deinit)(struct sof_client_dev *cdev);
+	int (*points_info)(struct sof_client_dev *cdev,
+			   struct sof_probe_point_desc **desc,
+			   size_t *num_desc, enum sof_probe_info_type type);
+	int (*point_print)(struct sof_client_dev *cdev, char *buf, size_t size,
+			   struct sof_probe_point_desc *desc);
+	int (*points_add)(struct sof_client_dev *cdev,
+			  struct sof_probe_point_desc *desc,
+			  size_t num_desc);
+	int (*points_remove)(struct sof_client_dev *cdev,
+			     unsigned int *buffer_id, size_t num_buffer_id);
+};
+
+extern const struct sof_probes_ipc_ops ipc3_probe_ops;
+extern const struct sof_probes_ipc_ops ipc4_probe_ops;
+
+struct sof_probes_priv {
+	struct dentry *dfs_points;
+	struct dentry *dfs_points_remove;
+	u32 extractor_stream_tag;
+	struct snd_soc_card card;
+	void *ipc_priv;
+
+	const struct sof_probes_host_ops *host_ops;
+	const struct sof_probes_ipc_ops *ipc_ops;
+};
+
+#endif