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, 32 insertions, 0 deletions

diff --git a/drivers/net/phy/phylib-internal.h b/drivers/net/phy/phylib-internal.h
new file mode 100644
index 000000000..664ed7faa
--- /dev/null
+++ b/drivers/net/phy/phylib-internal.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * phylib-internal header
+ */
+
+#ifndef __PHYLIB_INTERNAL_H
+#define __PHYLIB_INTERNAL_H
+
+struct mdio_device;
+struct phy_device;
+
+extern const struct bus_type mdio_bus_type;
+extern const struct class mdio_bus_class;
+
+/*
+ * phy_supported_speeds - return all speeds currently supported by a PHY device
+ */
+unsigned int phy_supported_speeds(struct phy_device *phy,
+				  unsigned int *speeds,
+				  unsigned int size);
+void of_set_phy_supported(struct phy_device *phydev);
+void of_set_phy_eee_broken(struct phy_device *phydev);
+void of_set_phy_timing_role(struct phy_device *phydev);
+int phy_speed_down_core(struct phy_device *phydev);
+void phy_check_downshift(struct phy_device *phydev);
+
+int mdiobus_register_device(struct mdio_device *mdiodev);
+int mdiobus_unregister_device(struct mdio_device *mdiodev);
+
+int genphy_c45_read_eee_adv(struct phy_device *phydev, unsigned long *adv);
+
+#endif /* __PHYLIB_INTERNAL_H */