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 --- drivers/net/eql.c | 611 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 611 insertions(+) create mode 100644 drivers/net/eql.c (limited to 'drivers/net/eql.c') diff --git a/drivers/net/eql.c b/drivers/net/eql.c new file mode 100644 index 000000000..06083b984 --- /dev/null +++ b/drivers/net/eql.c @@ -0,0 +1,611 @@ +/* + * Equalizer Load-balancer for serial network interfaces. + * + * (c) Copyright 1995 Simon "Guru Aleph-Null" Janes + * NCM: Network and Communications Management, Inc. + * + * (c) Copyright 2002 David S. Miller (davem@redhat.com) + * + * This software may be used and distributed according to the terms + * of the GNU General Public License, incorporated herein by reference. + * + * The author may be reached as simon@ncm.com, or C/O + * NCM + * Attn: Simon Janes + * 6803 Whittier Ave + * McLean VA 22101 + * Phone: 1-703-847-0040 ext 103 + */ + +/* + * Sources: + * skeleton.c by Donald Becker. + * Inspirations: + * The Harried and Overworked Alan Cox + * Conspiracies: + * The Alan Cox and Mike McLagan plot to get someone else to do the code, + * which turned out to be me. + */ + +/* + * $Log: eql.c,v $ + * Revision 1.2 1996/04/11 17:51:52 guru + * Added one-line eql_remove_slave patch. + * + * Revision 1.1 1996/04/11 17:44:17 guru + * Initial revision + * + * Revision 3.13 1996/01/21 15:17:18 alan + * tx_queue_len changes. + * reformatted. + * + * Revision 3.12 1995/03/22 21:07:51 anarchy + * Added capable() checks on configuration. + * Moved header file. + * + * Revision 3.11 1995/01/19 23:14:31 guru + * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) - + * (priority_Bps) + bytes_queued * 8; + * + * Revision 3.10 1995/01/19 23:07:53 guru + * back to + * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) - + * (priority_Bps) + bytes_queued; + * + * Revision 3.9 1995/01/19 22:38:20 guru + * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) - + * (priority_Bps) + bytes_queued * 4; + * + * Revision 3.8 1995/01/19 22:30:55 guru + * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) - + * (priority_Bps) + bytes_queued * 2; + * + * Revision 3.7 1995/01/19 21:52:35 guru + * printk's trimmed out. + * + * Revision 3.6 1995/01/19 21:49:56 guru + * This is working pretty well. I gained 1 K/s in speed.. now it's just + * robustness and printk's to be diked out. + * + * Revision 3.5 1995/01/18 22:29:59 guru + * still crashes the kernel when the lock_wait thing is woken up. + * + * Revision 3.4 1995/01/18 21:59:47 guru + * Broken set-bit locking snapshot + * + * Revision 3.3 1995/01/17 22:09:18 guru + * infinite sleep in a lock somewhere.. + * + * Revision 3.2 1995/01/15 16:46:06 guru + * Log trimmed of non-pertinent 1.x branch messages + * + * Revision 3.1 1995/01/15 14:41:45 guru + * New Scheduler and timer stuff... + * + * Revision 1.15 1995/01/15 14:29:02 guru + * Will make 1.14 (now 1.15) the 3.0 branch, and the 1.12 the 2.0 branch, the one + * with the dumber scheduler + * + * Revision 1.14 1995/01/15 02:37:08 guru + * shock.. the kept-new-versions could have zonked working + * stuff.. shudder + * + * Revision 1.13 1995/01/15 02:36:31 guru + * big changes + * + * scheduler was torn out and replaced with something smarter + * + * global names not prefixed with eql_ were renamed to protect + * against namespace collisions + * + * a few more abstract interfaces were added to facilitate any + * potential change of datastructure. the driver is still using + * a linked list of slaves. going to a heap would be a bit of + * an overkill. + * + * this compiles fine with no warnings. + * + * the locking mechanism and timer stuff must be written however, + * this version will not work otherwise + * + * Sorry, I had to rewrite most of this for 2.5.x -DaveM + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +#include + +static int eql_open(struct net_device *dev); +static int eql_close(struct net_device *dev); +static int eql_siocdevprivate(struct net_device *dev, struct ifreq *ifr, + void __user *data, int cmd); +static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev); + +#define eql_is_slave(dev) ((dev->flags & IFF_SLAVE) == IFF_SLAVE) +#define eql_is_master(dev) ((dev->flags & IFF_MASTER) == IFF_MASTER) + +static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave); + +static void eql_timer(struct timer_list *t) +{ + equalizer_t *eql = timer_container_of(eql, t, timer); + struct list_head *this, *tmp, *head; + + spin_lock(&eql->queue.lock); + head = &eql->queue.all_slaves; + list_for_each_safe(this, tmp, head) { + slave_t *slave = list_entry(this, slave_t, list); + + if ((slave->dev->flags & IFF_UP) == IFF_UP) { + slave->bytes_queued -= slave->priority_Bps; + if (slave->bytes_queued < 0) + slave->bytes_queued = 0; + } else { + eql_kill_one_slave(&eql->queue, slave); + } + + } + spin_unlock(&eql->queue.lock); + + eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL; + add_timer(&eql->timer); +} + +static const char version[] __initconst = + "Equalizer2002: Simon Janes (simon@ncm.com) and David S. Miller (davem@redhat.com)"; + +static const struct net_device_ops eql_netdev_ops = { + .ndo_open = eql_open, + .ndo_stop = eql_close, + .ndo_siocdevprivate = eql_siocdevprivate, + .ndo_start_xmit = eql_slave_xmit, +}; + +static void __init eql_setup(struct net_device *dev) +{ + equalizer_t *eql = netdev_priv(dev); + + timer_setup(&eql->timer, eql_timer, 0); + eql->timer.expires = jiffies + EQL_DEFAULT_RESCHED_IVAL; + + spin_lock_init(&eql->queue.lock); + INIT_LIST_HEAD(&eql->queue.all_slaves); + eql->queue.master_dev = dev; + + dev->netdev_ops = &eql_netdev_ops; + + /* + * Now we undo some of the things that eth_setup does + * that we don't like + */ + + dev->mtu = EQL_DEFAULT_MTU; /* set to 576 in if_eql.h */ + dev->flags = IFF_MASTER; + + dev->type = ARPHRD_SLIP; + dev->tx_queue_len = 5; /* Hands them off fast */ + netif_keep_dst(dev); +} + +static int eql_open(struct net_device *dev) +{ + equalizer_t *eql = netdev_priv(dev); + + /* XXX We should force this off automatically for the user. */ + netdev_info(dev, + "remember to turn off Van-Jacobson compression on your slave devices\n"); + + BUG_ON(!list_empty(&eql->queue.all_slaves)); + + eql->min_slaves = 1; + eql->max_slaves = EQL_DEFAULT_MAX_SLAVES; /* 4 usually... */ + + add_timer(&eql->timer); + + return 0; +} + +static void eql_kill_one_slave(slave_queue_t *queue, slave_t *slave) +{ + list_del(&slave->list); + queue->num_slaves--; + slave->dev->flags &= ~IFF_SLAVE; + netdev_put(slave->dev, &slave->dev_tracker); + kfree(slave); +} + +static void eql_kill_slave_queue(slave_queue_t *queue) +{ + struct list_head *head, *tmp, *this; + + spin_lock_bh(&queue->lock); + + head = &queue->all_slaves; + list_for_each_safe(this, tmp, head) { + slave_t *s = list_entry(this, slave_t, list); + + eql_kill_one_slave(queue, s); + } + + spin_unlock_bh(&queue->lock); +} + +static int eql_close(struct net_device *dev) +{ + equalizer_t *eql = netdev_priv(dev); + + /* + * The timer has to be stopped first before we start hacking away + * at the data structure it scans every so often... + */ + + timer_delete_sync(&eql->timer); + + eql_kill_slave_queue(&eql->queue); + + return 0; +} + +static int eql_enslave(struct net_device *dev, slaving_request_t __user *srq); +static int eql_emancipate(struct net_device *dev, slaving_request_t __user *srq); + +static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *sc); +static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *sc); + +static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mc); +static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mc); + +static int eql_siocdevprivate(struct net_device *dev, struct ifreq *ifr, + void __user *data, int cmd) +{ + if (cmd != EQL_GETMASTRCFG && cmd != EQL_GETSLAVECFG && + !capable(CAP_NET_ADMIN)) + return -EPERM; + + if (in_compat_syscall()) /* to be implemented */ + return -EOPNOTSUPP; + + switch (cmd) { + case EQL_ENSLAVE: + return eql_enslave(dev, data); + case EQL_EMANCIPATE: + return eql_emancipate(dev, data); + case EQL_GETSLAVECFG: + return eql_g_slave_cfg(dev, data); + case EQL_SETSLAVECFG: + return eql_s_slave_cfg(dev, data); + case EQL_GETMASTRCFG: + return eql_g_master_cfg(dev, data); + case EQL_SETMASTRCFG: + return eql_s_master_cfg(dev, data); + default: + return -EOPNOTSUPP; + } +} + +/* queue->lock must be held */ +static slave_t *__eql_schedule_slaves(slave_queue_t *queue) +{ + unsigned long best_load = ~0UL; + struct list_head *this, *tmp, *head; + slave_t *best_slave; + + best_slave = NULL; + + /* Make a pass to set the best slave. */ + head = &queue->all_slaves; + list_for_each_safe(this, tmp, head) { + slave_t *slave = list_entry(this, slave_t, list); + unsigned long slave_load, bytes_queued, priority_Bps; + + /* Go through the slave list once, updating best_slave + * whenever a new best_load is found. + */ + bytes_queued = slave->bytes_queued; + priority_Bps = slave->priority_Bps; + if ((slave->dev->flags & IFF_UP) == IFF_UP) { + slave_load = (~0UL - (~0UL / 2)) - + (priority_Bps) + bytes_queued * 8; + + if (slave_load < best_load) { + best_load = slave_load; + best_slave = slave; + } + } else { + /* We found a dead slave, kill it. */ + eql_kill_one_slave(queue, slave); + } + } + return best_slave; +} + +static netdev_tx_t eql_slave_xmit(struct sk_buff *skb, struct net_device *dev) +{ + equalizer_t *eql = netdev_priv(dev); + slave_t *slave; + + spin_lock(&eql->queue.lock); + + slave = __eql_schedule_slaves(&eql->queue); + if (slave) { + struct net_device *slave_dev = slave->dev; + + skb->dev = slave_dev; + skb->priority = TC_PRIO_FILLER; + slave->bytes_queued += skb->len; + dev_queue_xmit(skb); + dev->stats.tx_packets++; + } else { + dev->stats.tx_dropped++; + dev_kfree_skb(skb); + } + + spin_unlock(&eql->queue.lock); + + return NETDEV_TX_OK; +} + +/* + * Private ioctl functions + */ + +/* queue->lock must be held */ +static slave_t *__eql_find_slave_dev(slave_queue_t *queue, struct net_device *dev) +{ + struct list_head *this, *head; + + head = &queue->all_slaves; + list_for_each(this, head) { + slave_t *slave = list_entry(this, slave_t, list); + + if (slave->dev == dev) + return slave; + } + + return NULL; +} + +static inline int eql_is_full(slave_queue_t *queue) +{ + equalizer_t *eql = netdev_priv(queue->master_dev); + + if (queue->num_slaves >= eql->max_slaves) + return 1; + return 0; +} + +/* queue->lock must be held */ +static int __eql_insert_slave(slave_queue_t *queue, slave_t *slave) +{ + if (!eql_is_full(queue)) { + slave_t *duplicate_slave = NULL; + + duplicate_slave = __eql_find_slave_dev(queue, slave->dev); + if (duplicate_slave) + eql_kill_one_slave(queue, duplicate_slave); + + netdev_hold(slave->dev, &slave->dev_tracker, GFP_ATOMIC); + list_add(&slave->list, &queue->all_slaves); + queue->num_slaves++; + slave->dev->flags |= IFF_SLAVE; + + return 0; + } + + return -ENOSPC; +} + +static int eql_enslave(struct net_device *master_dev, slaving_request_t __user *srqp) +{ + struct net_device *slave_dev; + slaving_request_t srq; + + if (copy_from_user(&srq, srqp, sizeof (slaving_request_t))) + return -EFAULT; + + slave_dev = __dev_get_by_name(&init_net, srq.slave_name); + if (!slave_dev) + return -ENODEV; + + if ((master_dev->flags & IFF_UP) == IFF_UP) { + /* slave is not a master & not already a slave: */ + if (!eql_is_master(slave_dev) && !eql_is_slave(slave_dev)) { + slave_t *s = kzalloc_obj(*s); + equalizer_t *eql = netdev_priv(master_dev); + int ret; + + if (!s) + return -ENOMEM; + + s->dev = slave_dev; + s->priority = srq.priority; + s->priority_bps = srq.priority; + s->priority_Bps = srq.priority / 8; + + spin_lock_bh(&eql->queue.lock); + ret = __eql_insert_slave(&eql->queue, s); + if (ret) + kfree(s); + + spin_unlock_bh(&eql->queue.lock); + + return ret; + } + } + + return -EINVAL; +} + +static int eql_emancipate(struct net_device *master_dev, slaving_request_t __user *srqp) +{ + equalizer_t *eql = netdev_priv(master_dev); + struct net_device *slave_dev; + slaving_request_t srq; + int ret; + + if (copy_from_user(&srq, srqp, sizeof (slaving_request_t))) + return -EFAULT; + + slave_dev = __dev_get_by_name(&init_net, srq.slave_name); + if (!slave_dev) + return -ENODEV; + + ret = -EINVAL; + spin_lock_bh(&eql->queue.lock); + if (eql_is_slave(slave_dev)) { + slave_t *slave = __eql_find_slave_dev(&eql->queue, slave_dev); + if (slave) { + eql_kill_one_slave(&eql->queue, slave); + ret = 0; + } + } + spin_unlock_bh(&eql->queue.lock); + + return ret; +} + +static int eql_g_slave_cfg(struct net_device *dev, slave_config_t __user *scp) +{ + equalizer_t *eql = netdev_priv(dev); + slave_t *slave; + struct net_device *slave_dev; + slave_config_t sc; + int ret; + + if (copy_from_user(&sc, scp, sizeof (slave_config_t))) + return -EFAULT; + + slave_dev = __dev_get_by_name(&init_net, sc.slave_name); + if (!slave_dev) + return -ENODEV; + + ret = -EINVAL; + + spin_lock_bh(&eql->queue.lock); + if (eql_is_slave(slave_dev)) { + slave = __eql_find_slave_dev(&eql->queue, slave_dev); + if (slave) { + sc.priority = slave->priority; + ret = 0; + } + } + spin_unlock_bh(&eql->queue.lock); + + if (!ret && copy_to_user(scp, &sc, sizeof (slave_config_t))) + ret = -EFAULT; + + return ret; +} + +static int eql_s_slave_cfg(struct net_device *dev, slave_config_t __user *scp) +{ + slave_t *slave; + equalizer_t *eql; + struct net_device *slave_dev; + slave_config_t sc; + int ret; + + if (copy_from_user(&sc, scp, sizeof (slave_config_t))) + return -EFAULT; + + slave_dev = __dev_get_by_name(&init_net, sc.slave_name); + if (!slave_dev) + return -ENODEV; + + ret = -EINVAL; + + eql = netdev_priv(dev); + spin_lock_bh(&eql->queue.lock); + if (eql_is_slave(slave_dev)) { + slave = __eql_find_slave_dev(&eql->queue, slave_dev); + if (slave) { + slave->priority = sc.priority; + slave->priority_bps = sc.priority; + slave->priority_Bps = sc.priority / 8; + ret = 0; + } + } + spin_unlock_bh(&eql->queue.lock); + + return ret; +} + +static int eql_g_master_cfg(struct net_device *dev, master_config_t __user *mcp) +{ + equalizer_t *eql; + master_config_t mc; + + memset(&mc, 0, sizeof(master_config_t)); + + if (eql_is_master(dev)) { + eql = netdev_priv(dev); + mc.max_slaves = eql->max_slaves; + mc.min_slaves = eql->min_slaves; + if (copy_to_user(mcp, &mc, sizeof (master_config_t))) + return -EFAULT; + return 0; + } + return -EINVAL; +} + +static int eql_s_master_cfg(struct net_device *dev, master_config_t __user *mcp) +{ + equalizer_t *eql; + master_config_t mc; + + if (copy_from_user(&mc, mcp, sizeof (master_config_t))) + return -EFAULT; + + if (eql_is_master(dev)) { + eql = netdev_priv(dev); + eql->max_slaves = mc.max_slaves; + eql->min_slaves = mc.min_slaves; + return 0; + } + return -EINVAL; +} + +static struct net_device *dev_eql; + +static int __init eql_init_module(void) +{ + int err; + + pr_info("%s\n", version); + + dev_eql = alloc_netdev(sizeof(equalizer_t), "eql", NET_NAME_UNKNOWN, + eql_setup); + if (!dev_eql) + return -ENOMEM; + + err = register_netdev(dev_eql); + if (err) + free_netdev(dev_eql); + return err; +} + +static void __exit eql_cleanup_module(void) +{ + unregister_netdev(dev_eql); + free_netdev(dev_eql); +} + +module_init(eql_init_module); +module_exit(eql_cleanup_module); +MODULE_DESCRIPTION("Equalizer Load-balancer for serial network interfaces"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1