From d8bd2d442bb2688b428ac7164e5dc6d95d4fa65b Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Thu, 5 Sep 2019 23:01:22 +0000 Subject: [PATCH] Drivers: hv: vmbus: Resume after fixing up old primary channels When the host re-offers the primary channels upon resume, the host only guarantees the Instance GUID doesn't change, so vmbus_bus_suspend() should invalidate channel->offermsg.child_relid and figure out the number of primary channels that need to be fixed up upon resume. Upon resume, vmbus_onoffer() finds the old channel structs, and maps the new offers to the old channels, and fixes up the old structs, and finally the resume callbacks of the VSC drivers will re-open the channels. Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Signed-off-by: Sasha Levin --- drivers/hv/channel_mgmt.c | 89 +++++++++++++++++++++++++++++---------- drivers/hv/connection.c | 2 + drivers/hv/hyperv_vmbus.h | 14 ++++++ drivers/hv/vmbus_drv.c | 17 ++++++++ include/linux/hyperv.h | 3 ++ 5 files changed, 103 insertions(+), 22 deletions(-) diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 5518d031f62a..8eb167540b4f 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -407,7 +407,15 @@ void hv_process_channel_removal(struct vmbus_channel *channel) cpumask_clear_cpu(channel->target_cpu, &primary_channel->alloced_cpus_in_node); - vmbus_release_relid(channel->offermsg.child_relid); + /* + * Upon suspend, an in-use hv_sock channel is marked as "rescinded" and + * the relid is invalidated; after hibernation, when the user-space app + * destroys the channel, the relid is INVALID_RELID, and in this case + * it's unnecessary and unsafe to release the old relid, since the same + * relid can refer to a completely different channel now. + */ + if (channel->offermsg.child_relid != INVALID_RELID) + vmbus_release_relid(channel->offermsg.child_relid); free_channel(channel); } @@ -851,6 +859,36 @@ void vmbus_initiate_unload(bool crash) vmbus_wait_for_unload(); } +static void check_ready_for_resume_event(void) +{ + /* + * If all the old primary channels have been fixed up, then it's safe + * to resume. + */ + if (atomic_dec_and_test(&vmbus_connection.nr_chan_fixup_on_resume)) + complete(&vmbus_connection.ready_for_resume_event); +} + +static void vmbus_setup_channel_state(struct vmbus_channel *channel, + struct vmbus_channel_offer_channel *offer) +{ + /* + * Setup state for signalling the host. + */ + channel->sig_event = VMBUS_EVENT_CONNECTION_ID; + + if (vmbus_proto_version != VERSION_WS2008) { + channel->is_dedicated_interrupt = + (offer->is_dedicated_interrupt != 0); + channel->sig_event = offer->connection_id; + } + + memcpy(&channel->offermsg, offer, + sizeof(struct vmbus_channel_offer_channel)); + channel->monitor_grp = (u8)offer->monitorid / 32; + channel->monitor_bit = (u8)offer->monitorid % 32; +} + /* * find_primary_channel_by_offer - Get the channel object given the new offer. * This is only used in the resume path of hibernation. @@ -902,14 +940,29 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr) atomic_dec(&vmbus_connection.offer_in_progress); /* - * We're resuming from hibernation: we expect the host to send - * exactly the same offers that we had before the hibernation. + * We're resuming from hibernation: all the sub-channel and + * hv_sock channels we had before the hibernation should have + * been cleaned up, and now we must be seeing a re-offered + * primary channel that we had before the hibernation. */ - offer_sz = sizeof(*offer); - if (memcmp(offer, &oldchannel->offermsg, offer_sz) == 0) - return; - pr_debug("Mismatched offer from the host (relid=%d)\n", + WARN_ON(oldchannel->offermsg.child_relid != INVALID_RELID); + /* Fix up the relid. */ + oldchannel->offermsg.child_relid = offer->child_relid; + + offer_sz = sizeof(*offer); + if (memcmp(offer, &oldchannel->offermsg, offer_sz) == 0) { + check_ready_for_resume_event(); + return; + } + + /* + * This is not an error, since the host can also change the + * other field(s) of the offer, e.g. on WS RS5 (Build 17763), + * the offer->connection_id of the Mellanox VF vmbus device + * can change when the host reoffers the device upon resume. + */ + pr_debug("vmbus offer changed: relid=%d\n", offer->child_relid); print_hex_dump_debug("Old vmbus offer: ", DUMP_PREFIX_OFFSET, @@ -917,6 +970,12 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr) false); print_hex_dump_debug("New vmbus offer: ", DUMP_PREFIX_OFFSET, 16, 4, offer, offer_sz, false); + + /* Fix up the old channel. */ + vmbus_setup_channel_state(oldchannel, offer); + + check_ready_for_resume_event(); + return; } @@ -929,21 +988,7 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr) return; } - /* - * Setup state for signalling the host. - */ - newchannel->sig_event = VMBUS_EVENT_CONNECTION_ID; - - if (vmbus_proto_version != VERSION_WS2008) { - newchannel->is_dedicated_interrupt = - (offer->is_dedicated_interrupt != 0); - newchannel->sig_event = offer->connection_id; - } - - memcpy(&newchannel->offermsg, offer, - sizeof(struct vmbus_channel_offer_channel)); - newchannel->monitor_grp = (u8)offer->monitorid / 32; - newchannel->monitor_bit = (u8)offer->monitorid % 32; + vmbus_setup_channel_state(newchannel, offer); vmbus_process_offer(newchannel); } diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index 99851ea682eb..6e4c015783ff 100644 --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -29,6 +29,8 @@ struct vmbus_connection vmbus_connection = { .ready_for_suspend_event= COMPLETION_INITIALIZER( vmbus_connection.ready_for_suspend_event), + .ready_for_resume_event = COMPLETION_INITIALIZER( + vmbus_connection.ready_for_resume_event), }; EXPORT_SYMBOL_GPL(vmbus_connection); diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 974b747ca1fc..f7a5f5615f34 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -272,6 +272,20 @@ struct vmbus_connection { * drop to zero. */ struct completion ready_for_suspend_event; + + /* + * The number of primary channels that should be "fixed up" + * upon resume: these channels are re-offered upon resume, and some + * fields of the channel offers (i.e. child_relid and connection_id) + * can change, so the old offermsg must be fixed up, before the resume + * callbacks of the VSC drivers start to further touch the channels. + */ + atomic_t nr_chan_fixup_on_resume; + /* + * vmbus_bus_resume() waits for "nr_chan_fixup_on_resume" to + * drop to zero. + */ + struct completion ready_for_resume_event; }; diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 32ec951d334f..391f0b225c9a 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2164,9 +2164,17 @@ static int vmbus_bus_suspend(struct device *dev) if (atomic_read(&vmbus_connection.nr_chan_close_on_suspend) > 0) wait_for_completion(&vmbus_connection.ready_for_suspend_event); + WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0); + mutex_lock(&vmbus_connection.channel_mutex); list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { + /* + * Invalidate the field. Upon resume, vmbus_onoffer() will fix + * up the field, and the other fields (if necessary). + */ + channel->offermsg.child_relid = INVALID_RELID; + if (is_hvsock_channel(channel)) { if (!channel->rescind) { pr_err("hv_sock channel not rescinded!\n"); @@ -2181,6 +2189,8 @@ static int vmbus_bus_suspend(struct device *dev) WARN_ON_ONCE(1); } spin_unlock_irqrestore(&channel->lock, flags); + + atomic_inc(&vmbus_connection.nr_chan_fixup_on_resume); } mutex_unlock(&vmbus_connection.channel_mutex); @@ -2189,6 +2199,9 @@ static int vmbus_bus_suspend(struct device *dev) vmbus_connection.conn_state = DISCONNECTED; + /* Reset the event for the next resume. */ + reinit_completion(&vmbus_connection.ready_for_resume_event); + return 0; } @@ -2223,8 +2236,12 @@ static int vmbus_bus_resume(struct device *dev) if (ret != 0) return ret; + WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) == 0); + vmbus_request_offers(); + wait_for_completion(&vmbus_connection.ready_for_resume_event); + /* Reset the event for the next suspend. */ reinit_completion(&vmbus_connection.ready_for_suspend_event); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 8a60e7766037..a3aa9e9ef6f2 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -426,6 +426,9 @@ enum vmbus_channel_message_type { CHANNELMSG_COUNT }; +/* Hyper-V supports about 2048 channels, and the RELIDs start with 1. */ +#define INVALID_RELID U32_MAX + struct vmbus_channel_message_header { enum vmbus_channel_message_type msgtype; u32 padding;