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 --- net/ethtool/pause.c | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 222 insertions(+) create mode 100644 net/ethtool/pause.c (limited to 'net/ethtool/pause.c') diff --git a/net/ethtool/pause.c b/net/ethtool/pause.c new file mode 100644 index 000000000..ccaec8e87 --- /dev/null +++ b/net/ethtool/pause.c @@ -0,0 +1,222 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include "common.h" +#include "netlink.h" + +struct pause_req_info { + struct ethnl_req_info base; + enum ethtool_mac_stats_src src; +}; + +#define PAUSE_REQINFO(__req_base) \ + container_of(__req_base, struct pause_req_info, base) + +struct pause_reply_data { + struct ethnl_reply_data base; + struct ethtool_pauseparam pauseparam; + struct ethtool_pause_stats pausestat; +}; + +#define PAUSE_REPDATA(__reply_base) \ + container_of(__reply_base, struct pause_reply_data, base) + +const struct nla_policy ethnl_pause_get_policy[] = { + [ETHTOOL_A_PAUSE_HEADER] = + NLA_POLICY_NESTED(ethnl_header_policy_stats), + [ETHTOOL_A_PAUSE_STATS_SRC] = + NLA_POLICY_MAX(NLA_U32, ETHTOOL_MAC_STATS_SRC_PMAC), +}; + +static int pause_parse_request(struct ethnl_req_info *req_base, + const struct genl_info *info, + struct nlattr **tb, + struct netlink_ext_ack *extack) +{ + enum ethtool_mac_stats_src src = ETHTOOL_MAC_STATS_SRC_AGGREGATE; + struct pause_req_info *req_info = PAUSE_REQINFO(req_base); + + if (tb[ETHTOOL_A_PAUSE_STATS_SRC]) { + if (!(req_base->flags & ETHTOOL_FLAG_STATS)) { + NL_SET_ERR_MSG_MOD(extack, + "ETHTOOL_FLAG_STATS must be set when requesting a source of stats"); + return -EINVAL; + } + + src = nla_get_u32(tb[ETHTOOL_A_PAUSE_STATS_SRC]); + } + + req_info->src = src; + + return 0; +} + +static int pause_prepare_data(const struct ethnl_req_info *req_base, + struct ethnl_reply_data *reply_base, + const struct genl_info *info) +{ + const struct pause_req_info *req_info = PAUSE_REQINFO(req_base); + struct pause_reply_data *data = PAUSE_REPDATA(reply_base); + enum ethtool_mac_stats_src src = req_info->src; + struct net_device *dev = reply_base->dev; + int ret; + + if (!dev->ethtool_ops->get_pauseparam) + return -EOPNOTSUPP; + + ethtool_stats_init((u64 *)&data->pausestat, + sizeof(data->pausestat) / 8); + data->pausestat.src = src; + + ret = ethnl_ops_begin(dev); + if (ret < 0) + return ret; + + if ((src == ETHTOOL_MAC_STATS_SRC_EMAC || + src == ETHTOOL_MAC_STATS_SRC_PMAC) && + !__ethtool_dev_mm_supported(dev)) { + NL_SET_ERR_MSG_MOD(info->extack, + "Device does not support MAC merge layer"); + ethnl_ops_complete(dev); + return -EOPNOTSUPP; + } + + dev->ethtool_ops->get_pauseparam(dev, &data->pauseparam); + if (req_base->flags & ETHTOOL_FLAG_STATS && + dev->ethtool_ops->get_pause_stats) + dev->ethtool_ops->get_pause_stats(dev, &data->pausestat); + + ethnl_ops_complete(dev); + + return 0; +} + +static int pause_reply_size(const struct ethnl_req_info *req_base, + const struct ethnl_reply_data *reply_base) +{ + int n = nla_total_size(sizeof(u8)) + /* _PAUSE_AUTONEG */ + nla_total_size(sizeof(u8)) + /* _PAUSE_RX */ + nla_total_size(sizeof(u8)); /* _PAUSE_TX */ + + if (req_base->flags & ETHTOOL_FLAG_STATS) + n += nla_total_size(0) + /* _PAUSE_STATS */ + nla_total_size(sizeof(u32)) + /* _PAUSE_STATS_SRC */ + nla_total_size_64bit(sizeof(u64)) * ETHTOOL_PAUSE_STAT_CNT; + return n; +} + +static int ethtool_put_stat(struct sk_buff *skb, u64 val, u16 attrtype, + u16 padtype) +{ + if (val == ETHTOOL_STAT_NOT_SET) + return 0; + if (nla_put_u64_64bit(skb, attrtype, val, padtype)) + return -EMSGSIZE; + + return 0; +} + +static int pause_put_stats(struct sk_buff *skb, + const struct ethtool_pause_stats *pause_stats) +{ + const u16 pad = ETHTOOL_A_PAUSE_STAT_PAD; + struct nlattr *nest; + + if (nla_put_u32(skb, ETHTOOL_A_PAUSE_STATS_SRC, pause_stats->src)) + return -EMSGSIZE; + + nest = nla_nest_start(skb, ETHTOOL_A_PAUSE_STATS); + if (!nest) + return -EMSGSIZE; + + if (ethtool_put_stat(skb, pause_stats->tx_pause_frames, + ETHTOOL_A_PAUSE_STAT_TX_FRAMES, pad) || + ethtool_put_stat(skb, pause_stats->rx_pause_frames, + ETHTOOL_A_PAUSE_STAT_RX_FRAMES, pad) || + ethtool_put_stat(skb, pause_stats->tx_pause_storm_events, + ETHTOOL_A_PAUSE_STAT_TX_PAUSE_STORM_EVENTS, pad)) + goto err_cancel; + + nla_nest_end(skb, nest); + return 0; + +err_cancel: + nla_nest_cancel(skb, nest); + return -EMSGSIZE; +} + +static int pause_fill_reply(struct sk_buff *skb, + const struct ethnl_req_info *req_base, + const struct ethnl_reply_data *reply_base) +{ + const struct pause_reply_data *data = PAUSE_REPDATA(reply_base); + const struct ethtool_pauseparam *pauseparam = &data->pauseparam; + + if (nla_put_u8(skb, ETHTOOL_A_PAUSE_AUTONEG, !!pauseparam->autoneg) || + nla_put_u8(skb, ETHTOOL_A_PAUSE_RX, !!pauseparam->rx_pause) || + nla_put_u8(skb, ETHTOOL_A_PAUSE_TX, !!pauseparam->tx_pause)) + return -EMSGSIZE; + + if (req_base->flags & ETHTOOL_FLAG_STATS && + pause_put_stats(skb, &data->pausestat)) + return -EMSGSIZE; + + return 0; +} + +/* PAUSE_SET */ + +const struct nla_policy ethnl_pause_set_policy[] = { + [ETHTOOL_A_PAUSE_HEADER] = + NLA_POLICY_NESTED(ethnl_header_policy), + [ETHTOOL_A_PAUSE_AUTONEG] = { .type = NLA_U8 }, + [ETHTOOL_A_PAUSE_RX] = { .type = NLA_U8 }, + [ETHTOOL_A_PAUSE_TX] = { .type = NLA_U8 }, + [ETHTOOL_A_PAUSE_STATS_SRC] = { .type = NLA_REJECT }, +}; + +static int +ethnl_set_pause_validate(struct ethnl_req_info *req_info, + struct genl_info *info) +{ + const struct ethtool_ops *ops = req_info->dev->ethtool_ops; + + return ops->get_pauseparam && ops->set_pauseparam ? 1 : -EOPNOTSUPP; +} + +static int +ethnl_set_pause(struct ethnl_req_info *req_info, struct genl_info *info) +{ + struct net_device *dev = req_info->dev; + struct ethtool_pauseparam params = {}; + struct nlattr **tb = info->attrs; + bool mod = false; + int ret; + + dev->ethtool_ops->get_pauseparam(dev, ¶ms); + + ethnl_update_bool32(¶ms.autoneg, tb[ETHTOOL_A_PAUSE_AUTONEG], &mod); + ethnl_update_bool32(¶ms.rx_pause, tb[ETHTOOL_A_PAUSE_RX], &mod); + ethnl_update_bool32(¶ms.tx_pause, tb[ETHTOOL_A_PAUSE_TX], &mod); + if (!mod) + return 0; + + ret = dev->ethtool_ops->set_pauseparam(dev, ¶ms); + return ret < 0 ? ret : 1; +} + +const struct ethnl_request_ops ethnl_pause_request_ops = { + .request_cmd = ETHTOOL_MSG_PAUSE_GET, + .reply_cmd = ETHTOOL_MSG_PAUSE_GET_REPLY, + .hdr_attr = ETHTOOL_A_PAUSE_HEADER, + .req_info_size = sizeof(struct pause_req_info), + .reply_data_size = sizeof(struct pause_reply_data), + + .parse_request = pause_parse_request, + .prepare_data = pause_prepare_data, + .reply_size = pause_reply_size, + .fill_reply = pause_fill_reply, + + .set_validate = ethnl_set_pause_validate, + .set = ethnl_set_pause, + .set_ntf_cmd = ETHTOOL_MSG_PAUSE_NTF, +}; 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