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, 59 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/mt352.h b/drivers/media/dvb-frontends/mt352.h
new file mode 100644
index 000000000..acb1c3374
--- /dev/null
+++ b/drivers/media/dvb-frontends/mt352.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  Driver for Zarlink DVB-T MT352 demodulator
+ *
+ *  Written by Holger Waechtler <holger@qanu.de>
+ *	 and Daniel Mack <daniel@qanu.de>
+ *
+ *  AVerMedia AVerTV DVB-T 771 support by
+ *       Wolfram Joost <dbox2@frokaschwei.de>
+ *
+ *  Support for Samsung TDTC9251DH01C(M) tuner
+ *  Copyright (C) 2004 Antonio Mancuso <antonio.mancuso@digitaltelevision.it>
+ *                     Amauri  Celani  <acelani@essegi.net>
+ *
+ *  DVICO FusionHDTV DVB-T1 and DVICO FusionHDTV DVB-T Lite support by
+ *       Christopher Pascoe <c.pascoe@itee.uq.edu.au>
+ */
+
+#ifndef MT352_H
+#define MT352_H
+
+#include <linux/dvb/frontend.h>
+
+struct mt352_config
+{
+	/* the demodulator's i2c address */
+	u8 demod_address;
+
+	/* frequencies in kHz */
+	int adc_clock;  // default: 20480
+	int if2;        // default: 36166
+
+	/* set if no pll is connected to the secondary i2c bus */
+	int no_tuner;
+
+	/* Initialise the demodulator and PLL. Cannot be NULL */
+	int (*demod_init)(struct dvb_frontend* fe);
+};
+
+#if IS_REACHABLE(CONFIG_DVB_MT352)
+extern struct dvb_frontend* mt352_attach(const struct mt352_config* config,
+					 struct i2c_adapter* i2c);
+#else
+static inline struct dvb_frontend* mt352_attach(const struct mt352_config* config,
+					 struct i2c_adapter* i2c)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+	return NULL;
+}
+#endif // CONFIG_DVB_MT352
+
+static inline int mt352_write(struct dvb_frontend *fe, const u8 buf[], int len) {
+	int r = 0;
+	if (fe->ops.write)
+		r = fe->ops.write(fe, buf, len);
+	return r;
+}
+
+#endif // MT352_H