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, 43 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/sp2.h b/drivers/media/dvb-frontends/sp2.h
new file mode 100644
index 000000000..b5ace0d76
--- /dev/null
+++ b/drivers/media/dvb-frontends/sp2.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * CIMaX SP2/HF CI driver
+ *
+ * Copyright (C) 2014 Olli Salonen <olli.salonen@iki.fi>
+ */
+
+#ifndef SP2_H
+#define SP2_H
+
+#include <media/dvb_ca_en50221.h>
+
+/*
+ * I2C address
+ * 0x40 (port 0)
+ * 0x41 (port 1)
+ */
+struct sp2_config {
+	/* dvb_adapter to attach the ci to */
+	struct dvb_adapter *dvb_adap;
+
+	/* function ci_control handles the device specific ci ops */
+	void *ci_control;
+
+	/* priv is passed back to function ci_control */
+	void *priv;
+};
+
+extern int sp2_ci_read_attribute_mem(struct dvb_ca_en50221 *en50221,
+					int slot, int addr);
+extern int sp2_ci_write_attribute_mem(struct dvb_ca_en50221 *en50221,
+					int slot, int addr, u8 data);
+extern int sp2_ci_read_cam_control(struct dvb_ca_en50221 *en50221,
+					int slot, u8 addr);
+extern int sp2_ci_write_cam_control(struct dvb_ca_en50221 *en50221,
+					int slot, u8 addr, u8 data);
+extern int sp2_ci_slot_reset(struct dvb_ca_en50221 *en50221, int slot);
+extern int sp2_ci_slot_shutdown(struct dvb_ca_en50221 *en50221, int slot);
+extern int sp2_ci_slot_ts_enable(struct dvb_ca_en50221 *en50221, int slot);
+extern int sp2_ci_poll_slot_status(struct dvb_ca_en50221 *en50221,
+					int slot, int open);
+
+#endif