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, 34 insertions, 0 deletions

diff --git a/sound/firewire/fcp.h b/sound/firewire/fcp.h
new file mode 100644
index 000000000..512f7c409
--- /dev/null
+++ b/sound/firewire/fcp.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef SOUND_FIREWIRE_FCP_H_INCLUDED
+#define SOUND_FIREWIRE_FCP_H_INCLUDED
+
+#define	AVC_PLUG_INFO_BUF_BYTES	4
+
+struct fw_unit;
+
+/*
+ * AV/C Digital Interface Command Set General Specification 4.2
+ * (Sep 2004, 1394TA)
+ */
+enum avc_general_plug_dir {
+	AVC_GENERAL_PLUG_DIR_IN		= 0,
+	AVC_GENERAL_PLUG_DIR_OUT	= 1,
+	AVC_GENERAL_PLUG_DIR_COUNT
+};
+int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate,
+			    enum avc_general_plug_dir dir,
+			    unsigned short plug);
+int avc_general_get_sig_fmt(struct fw_unit *unit, unsigned int *rate,
+			    enum avc_general_plug_dir dir,
+			    unsigned short plug);
+int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type,
+			      unsigned int subunit_id, unsigned int subfunction,
+			      u8 info[AVC_PLUG_INFO_BUF_BYTES]);
+
+int fcp_avc_transaction(struct fw_unit *unit,
+			const void *command, unsigned int command_size,
+			void *response, unsigned int response_size,
+			unsigned int response_match_bytes);
+void fcp_bus_reset(struct fw_unit *unit);
+
+#endif