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, 41 insertions, 0 deletions

diff --git a/drivers/net/phy/phylib.h b/drivers/net/phy/phylib.h
new file mode 100644
index 000000000..c6e26ac6b
--- /dev/null
+++ b/drivers/net/phy/phylib.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * phylib header
+ */
+
+#ifndef __PHYLIB_H
+#define __PHYLIB_H
+
+struct device_node;
+struct phy_device;
+struct mii_bus;
+
+struct device_node *phy_package_get_node(struct phy_device *phydev);
+void *phy_package_get_priv(struct phy_device *phydev);
+void phy_package_lock(struct phy_device *phydev);
+void phy_package_unlock(struct phy_device *phydev);
+int __phy_package_read(struct phy_device *phydev, unsigned int addr_offset,
+		       u32 regnum);
+int __phy_package_write(struct phy_device *phydev, unsigned int addr_offset,
+			u32 regnum, u16 val);
+int __phy_package_read_mmd(struct phy_device *phydev,
+			   unsigned int addr_offset, int devad,
+			   u32 regnum);
+int __phy_package_write_mmd(struct phy_device *phydev,
+			    unsigned int addr_offset, int devad,
+			    u32 regnum, u16 val);
+bool phy_package_init_once(struct phy_device *phydev);
+bool phy_package_probe_once(struct phy_device *phydev);
+int phy_package_join(struct phy_device *phydev, int base_addr, size_t priv_size);
+int of_phy_package_join(struct phy_device *phydev, size_t priv_size);
+void phy_package_leave(struct phy_device *phydev);
+int devm_phy_package_join(struct device *dev, struct phy_device *phydev,
+			  int base_addr, size_t priv_size);
+int devm_of_phy_package_join(struct device *dev, struct phy_device *phydev,
+			     size_t priv_size);
+int mmd_phy_read(struct mii_bus *bus, int phy_addr, bool is_c45,
+		 int devad, u32 regnum);
+int mmd_phy_write(struct mii_bus *bus, int phy_addr, bool is_c45,
+		  int devad, u32 regnum, u16 val);
+
+#endif /* __PHYLIB_H */