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, 57 insertions, 0 deletions

diff --git a/sound/usb/endpoint.h b/sound/usb/endpoint.h
new file mode 100644
index 000000000..ba70f52f6
--- /dev/null
+++ b/sound/usb/endpoint.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_ENDPOINT_H
+#define __USBAUDIO_ENDPOINT_H
+
+#define SND_USB_ENDPOINT_TYPE_DATA     0
+#define SND_USB_ENDPOINT_TYPE_SYNC     1
+
+struct snd_usb_endpoint *snd_usb_get_endpoint(struct snd_usb_audio *chip,
+					      int ep_num);
+
+int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type);
+
+struct snd_usb_endpoint *
+snd_usb_endpoint_open(struct snd_usb_audio *chip,
+		      const struct audioformat *fp,
+		      const struct snd_pcm_hw_params *params,
+		      bool is_sync_ep,
+		      bool fixed_rate);
+void snd_usb_endpoint_close(struct snd_usb_audio *chip,
+			    struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
+				struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
+			     struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock);
+
+bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
+				 struct snd_usb_endpoint *ep,
+				 const struct audioformat *fp,
+				 const struct snd_pcm_hw_params *params);
+
+void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
+			       struct snd_usb_endpoint *data_ep,
+			       struct snd_usb_endpoint *sync_ep);
+void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
+				   int (*prepare)(struct snd_usb_substream *subs,
+						  struct urb *urb,
+						  bool in_stream_lock),
+				   void (*retire)(struct snd_usb_substream *subs,
+						  struct urb *urb),
+				   struct snd_usb_substream *data_subs);
+
+int snd_usb_endpoint_start(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending);
+void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_release(struct snd_usb_endpoint *ep);
+void snd_usb_endpoint_free_all(struct snd_usb_audio *chip);
+
+int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep);
+int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
+				      struct snd_urb_ctx *ctx, int idx,
+				      unsigned int avail);
+int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
+				      bool in_stream_lock);
+
+#endif /* __USBAUDIO_ENDPOINT_H */