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/netdevsim/tc.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 drivers/net/netdevsim/tc.c (limited to 'drivers/net/netdevsim/tc.c') diff --git a/drivers/net/netdevsim/tc.c b/drivers/net/netdevsim/tc.c new file mode 100644 index 000000000..a415e02a6 --- /dev/null +++ b/drivers/net/netdevsim/tc.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include + +#include "netdevsim.h" + +static int +nsim_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv) +{ + struct flow_cls_common_offload *common = type_data; + int err = 0; + + switch (type) { + case TC_SETUP_CLSBPF: + err = nsim_bpf_setup_tc_block_cb(type, type_data, cb_priv); + break; + case TC_SETUP_CLSFLOWER: + break; + default: + NSIM_EA(common->extack, "offload type not supported"); + err = -EOPNOTSUPP; + break; + } + + return err; +} + +static void nsim_taprio_stats(struct tc_taprio_qopt_stats *stats) +{ + stats->window_drops = 0; + stats->tx_overruns = 0; +} + +static int nsim_setup_tc_taprio(struct net_device *dev, + struct tc_taprio_qopt_offload *offload) +{ + int err = 0; + + switch (offload->cmd) { + case TAPRIO_CMD_REPLACE: + case TAPRIO_CMD_DESTROY: + break; + case TAPRIO_CMD_STATS: + nsim_taprio_stats(&offload->stats); + break; + default: + err = -EOPNOTSUPP; + } + + return err; +} + +static int nsim_setup_tc_ets(struct net_device *dev, + struct tc_ets_qopt_offload *offload) +{ + int err = 0; + + switch (offload->command) { + case TC_ETS_REPLACE: + case TC_ETS_DESTROY: + break; + case TC_ETS_STATS: + _bstats_update(offload->stats.bstats, 0, 0); + break; + default: + err = -EOPNOTSUPP; + } + + return err; +} + +static LIST_HEAD(nsim_block_cb_list); + +int +nsim_setup_tc(struct net_device *dev, enum tc_setup_type type, void *type_data) +{ + struct netdevsim *ns = netdev_priv(dev); + + switch (type) { + case TC_SETUP_QDISC_TAPRIO: + return nsim_setup_tc_taprio(dev, type_data); + case TC_SETUP_QDISC_ETS: + return nsim_setup_tc_ets(dev, type_data); + case TC_SETUP_BLOCK: + return flow_block_cb_setup_simple(type_data, + &nsim_block_cb_list, + nsim_setup_tc_block_cb, + ns, ns, true); + case TC_SETUP_FT: + return 0; + default: + return -EOPNOTSUPP; + } +} +ALLOW_ERROR_INJECTION(nsim_setup_tc, ERRNO); -- cgit v1.3.1