From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration 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 Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/net/inetpeer.h | 154 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 154 insertions(+) create mode 100644 include/net/inetpeer.h (limited to 'include/net/inetpeer.h') diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h new file mode 100644 index 000000000..414e9adf4 --- /dev/null +++ b/include/net/inetpeer.h @@ -0,0 +1,154 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * INETPEER - A storage for permanent information about peers + * + * Authors: Andrey V. Savochkin + */ + +#ifndef _NET_INETPEER_H +#define _NET_INETPEER_H + +#include +#include +#include +#include +#include +#include +#include + +/* IPv4 address key for cache lookups */ +struct ipv4_addr_key { + __be32 addr; + int vif; +}; + +#define INETPEER_MAXKEYSZ (sizeof(struct in6_addr) / sizeof(u32)) + +struct inetpeer_addr { + union { + struct ipv4_addr_key a4; + struct in6_addr a6; + u32 key[INETPEER_MAXKEYSZ]; + }; + __u16 family; +}; + +struct inet_peer { + struct rb_node rb_node; + u64 hash; + struct inetpeer_addr daddr; + + u32 metrics[RTAX_MAX]; + u32 rate_tokens; /* rate limiting for ICMP */ + u32 n_redirects; + unsigned long rate_last; + /* + * Once inet_peer is queued for deletion (refcnt == 0), following field + * is not available: rid + * We can share memory with rcu_head to help keep inet_peer small. + */ + union { + struct { + atomic_t rid; /* Frag reception counter */ + }; + struct rcu_head rcu; + }; + + /* following fields might be frequently dirtied */ + __u32 dtime; /* the time of last use of not referenced entries */ + refcount_t refcnt; +}; + +struct inet_peer_base { + struct rb_root rb_root; + seqlock_t lock; + int total; +}; + +void inet_peer_base_init(struct inet_peer_base *); + +void inet_initpeers(void) __init; + +#define INETPEER_METRICS_NEW (~(u32) 0) + +static inline void inetpeer_set_addr_v4(struct inetpeer_addr *iaddr, __be32 ip) +{ + iaddr->a4.addr = ip; + iaddr->a4.vif = 0; + iaddr->family = AF_INET; +} + +static inline __be32 inetpeer_get_addr_v4(struct inetpeer_addr *iaddr) +{ + return iaddr->a4.addr; +} + +static inline void inetpeer_set_addr_v6(struct inetpeer_addr *iaddr, + struct in6_addr *in6) +{ + iaddr->a6 = *in6; + iaddr->family = AF_INET6; +} + +static inline struct in6_addr *inetpeer_get_addr_v6(struct inetpeer_addr *iaddr) +{ + return &iaddr->a6; +} + +/* can be called with or without local BH being disabled */ +struct inet_peer *inet_getpeer(struct inet_peer_base *base, + const struct inetpeer_addr *daddr); + +static inline struct inet_peer *inet_getpeer_v4(struct inet_peer_base *base, + __be32 v4daddr, + int vif) +{ + struct inetpeer_addr daddr; + + daddr.a4.addr = v4daddr; + daddr.a4.vif = vif; + daddr.family = AF_INET; + return inet_getpeer(base, &daddr); +} + +static inline struct inet_peer *inet_getpeer_v6(struct inet_peer_base *base, + const struct in6_addr *v6daddr) +{ + struct inetpeer_addr daddr; + + daddr.a6 = *v6daddr; + daddr.family = AF_INET6; + return inet_getpeer(base, &daddr); +} + +static inline int inetpeer_addr_cmp(const struct inetpeer_addr *a, + const struct inetpeer_addr *b) +{ + int i, n; + + if (a->family != b->family) + return a->family < b->family ? -1 : 1; + + if (a->family == AF_INET) + n = sizeof(a->a4) / sizeof(u32); + else + n = sizeof(a->a6) / sizeof(u32); + + for (i = 0; i < n; i++) { + if (a->key[i] == b->key[i]) + continue; + if (a->key[i] < b->key[i]) + return -1; + return 1; + } + + return 0; +} + +/* can be called from BH context or outside */ +void inet_putpeer(struct inet_peer *p); +bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout); + +void inetpeer_invalidate_tree(struct inet_peer_base *); + +#endif /* _NET_INETPEER_H */ -- cgit v1.3.1