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, 100 insertions, 0 deletions

diff --git a/include/net/raw.h b/include/net/raw.h
new file mode 100644
index 000000000..66c0ffead
--- /dev/null
+++ b/include/net/raw.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Definitions for the RAW-IP module.
+ *
+ * Version:	@(#)raw.h	1.0.2	05/07/93
+ *
+ * Author:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ */
+#ifndef _RAW_H
+#define _RAW_H
+
+#include <net/inet_sock.h>
+#include <net/protocol.h>
+#include <net/netns/hash.h>
+#include <linux/hash.h>
+#include <linux/icmp.h>
+
+extern struct proto raw_prot;
+
+extern struct raw_hashinfo raw_v4_hashinfo;
+bool raw_v4_match(struct net *net, const struct sock *sk, unsigned short num,
+		  __be32 raddr, __be32 laddr, int dif, int sdif);
+
+int raw_abort(struct sock *sk, int err);
+void raw_icmp_error(struct sk_buff *, int, u32);
+int raw_local_deliver(struct sk_buff *, int);
+
+int raw_rcv(struct sock *, struct sk_buff *);
+
+#define RAW_HTABLE_LOG	8
+#define RAW_HTABLE_SIZE	(1U << RAW_HTABLE_LOG)
+
+struct raw_hashinfo {
+	spinlock_t lock;
+
+	struct hlist_head ht[RAW_HTABLE_SIZE] ____cacheline_aligned;
+};
+
+static inline u32 raw_hashfunc(const struct net *net, u32 proto)
+{
+	return hash_32(net_hash_mix(net) ^ proto, RAW_HTABLE_LOG);
+}
+
+static inline void raw_hashinfo_init(struct raw_hashinfo *hashinfo)
+{
+	int i;
+
+	spin_lock_init(&hashinfo->lock);
+	for (i = 0; i < RAW_HTABLE_SIZE; i++)
+		INIT_HLIST_HEAD(&hashinfo->ht[i]);
+}
+
+#ifdef CONFIG_PROC_FS
+int raw_proc_init(void);
+void raw_proc_exit(void);
+
+struct raw_iter_state {
+	struct seq_net_private p;
+	int bucket;
+};
+
+static inline struct raw_iter_state *raw_seq_private(struct seq_file *seq)
+{
+	return seq->private;
+}
+void *raw_seq_start(struct seq_file *seq, loff_t *pos);
+void *raw_seq_next(struct seq_file *seq, void *v, loff_t *pos);
+void raw_seq_stop(struct seq_file *seq, void *v);
+#endif
+
+int raw_hash_sk(struct sock *sk);
+void raw_unhash_sk(struct sock *sk);
+void raw_init(void);
+
+struct raw_sock {
+	/* inet_sock has to be the first member */
+	struct inet_sock   inet;
+	struct icmp_filter filter;
+	u32		   ipmr_table;
+	struct numa_drop_counters drop_counters;
+};
+
+#define raw_sk(ptr) container_of_const(ptr, struct raw_sock, inet.sk)
+
+static inline bool raw_sk_bound_dev_eq(struct net *net, int bound_dev_if,
+				       int dif, int sdif)
+{
+#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
+	return inet_bound_dev_eq(READ_ONCE(net->ipv4.sysctl_raw_l3mdev_accept),
+				 bound_dev_if, dif, sdif);
+#else
+	return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
+#endif
+}
+
+#endif	/* _RAW_H */