diff options
Diffstat (limited to 'drivers/hv/channel_mgmt.c')
| -rw-r--r-- | drivers/hv/channel_mgmt.c | 1507 |
1 files changed, 1507 insertions, 0 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c new file mode 100644 index 000000000..0c6c54061 --- /dev/null +++ b/drivers/hv/channel_mgmt.c @@ -0,0 +1,1507 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2009, Microsoft Corporation. + * + * Authors: + * Haiyang Zhang <haiyangz@microsoft.com> + * Hank Janssen <hjanssen@microsoft.com> + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/sched.h> +#include <linux/wait.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/cpu.h> +#include <linux/hyperv.h> +#include <asm/mshyperv.h> + +#include "hyperv_vmbus.h" + +static void init_vp_index(struct vmbus_channel *channel); + +const struct vmbus_device vmbus_devs[] = { + /* IDE */ + { .dev_type = HV_IDE, + HV_IDE_GUID, + .perf_device = true, + }, + + /* SCSI */ + { .dev_type = HV_SCSI, + HV_SCSI_GUID, + .perf_device = true, + }, + + /* Fibre Channel */ + { .dev_type = HV_FC, + HV_SYNTHFC_GUID, + .perf_device = true, + }, + + /* Synthetic NIC */ + { .dev_type = HV_NIC, + HV_NIC_GUID, + .perf_device = true, + }, + + /* Network Direct */ + { .dev_type = HV_ND, + HV_ND_GUID, + .perf_device = true, + }, + + /* PCIE */ + { .dev_type = HV_PCIE, + HV_PCIE_GUID, + .perf_device = false, + }, + + /* Synthetic Frame Buffer */ + { .dev_type = HV_FB, + HV_SYNTHVID_GUID, + .perf_device = false, + }, + + /* Synthetic Keyboard */ + { .dev_type = HV_KBD, + HV_KBD_GUID, + .perf_device = false, + }, + + /* Synthetic MOUSE */ + { .dev_type = HV_MOUSE, + HV_MOUSE_GUID, + .perf_device = false, + }, + + /* KVP */ + { .dev_type = HV_KVP, + HV_KVP_GUID, + .perf_device = false, + }, + + /* Time Synch */ + { .dev_type = HV_TS, + HV_TS_GUID, + .perf_device = false, + }, + + /* Heartbeat */ + { .dev_type = HV_HB, + HV_HEART_BEAT_GUID, + .perf_device = false, + }, + + /* Shutdown */ + { .dev_type = HV_SHUTDOWN, + HV_SHUTDOWN_GUID, + .perf_device = false, + }, + + /* File copy */ + { .dev_type = HV_FCOPY, + HV_FCOPY_GUID, + .perf_device = false, + }, + + /* Backup */ + { .dev_type = HV_BACKUP, + HV_VSS_GUID, + .perf_device = false, + }, + + /* Dynamic Memory */ + { .dev_type = HV_DM, + HV_DM_GUID, + .perf_device = false, + }, + + /* Unknown GUID */ + { .dev_type = HV_UNKNOWN, + .perf_device = false, + }, +}; + +static const struct { + guid_t guid; +} vmbus_unsupported_devs[] = { + { HV_AVMA1_GUID }, + { HV_AVMA2_GUID }, + { HV_RDV_GUID }, +}; + +/* + * The rescinded channel may be blocked waiting for a response from the host; + * take care of that. + */ +static void vmbus_rescind_cleanup(struct vmbus_channel *channel) +{ + struct vmbus_channel_msginfo *msginfo; + unsigned long flags; + + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + channel->rescind = true; + list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, + msglistentry) { + + if (msginfo->waiting_channel == channel) { + complete(&msginfo->waitevent); + break; + } + } + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +} + +static bool is_unsupported_vmbus_devs(const guid_t *guid) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(vmbus_unsupported_devs); i++) + if (guid_equal(guid, &vmbus_unsupported_devs[i].guid)) + return true; + return false; +} + +static u16 hv_get_dev_type(const struct vmbus_channel *channel) +{ + const guid_t *guid = &channel->offermsg.offer.if_type; + u16 i; + + if (is_hvsock_channel(channel) || is_unsupported_vmbus_devs(guid)) + return HV_UNKNOWN; + + for (i = HV_IDE; i < HV_UNKNOWN; i++) { + if (guid_equal(guid, &vmbus_devs[i].guid)) + return i; + } + pr_info("Unknown GUID: %pUl\n", guid); + return i; +} + +/** + * vmbus_prep_negotiate_resp() - Create default response for Negotiate message + * @icmsghdrp: Pointer to msg header structure + * @buf: Raw buffer channel data + * @fw_version: The framework versions we can support. + * @fw_vercnt: The size of @fw_version. + * @srv_version: The service versions we can support. + * @srv_vercnt: The size of @srv_version. + * @nego_fw_version: The selected framework version. + * @nego_srv_version: The selected service version. + * + * Note: Versions are given in decreasing order. + * + * Set up and fill in default negotiate response message. + * Mainly used by Hyper-V drivers. + */ +bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, + u8 *buf, const int *fw_version, int fw_vercnt, + const int *srv_version, int srv_vercnt, + int *nego_fw_version, int *nego_srv_version) +{ + int icframe_major, icframe_minor; + int icmsg_major, icmsg_minor; + int fw_major, fw_minor; + int srv_major, srv_minor; + int i, j; + bool found_match = false; + struct icmsg_negotiate *negop; + + icmsghdrp->icmsgsize = 0x10; + negop = (struct icmsg_negotiate *)&buf[ + sizeof(struct vmbuspipe_hdr) + + sizeof(struct icmsg_hdr)]; + + icframe_major = negop->icframe_vercnt; + icframe_minor = 0; + + icmsg_major = negop->icmsg_vercnt; + icmsg_minor = 0; + + /* + * Select the framework version number we will + * support. + */ + + for (i = 0; i < fw_vercnt; i++) { + fw_major = (fw_version[i] >> 16); + fw_minor = (fw_version[i] & 0xFFFF); + + for (j = 0; j < negop->icframe_vercnt; j++) { + if ((negop->icversion_data[j].major == fw_major) && + (negop->icversion_data[j].minor == fw_minor)) { + icframe_major = negop->icversion_data[j].major; + icframe_minor = negop->icversion_data[j].minor; + found_match = true; + break; + } + } + + if (found_match) + break; + } + + if (!found_match) + goto fw_error; + + found_match = false; + + for (i = 0; i < srv_vercnt; i++) { + srv_major = (srv_version[i] >> 16); + srv_minor = (srv_version[i] & 0xFFFF); + + for (j = negop->icframe_vercnt; + (j < negop->icframe_vercnt + negop->icmsg_vercnt); + j++) { + + if ((negop->icversion_data[j].major == srv_major) && + (negop->icversion_data[j].minor == srv_minor)) { + + icmsg_major = negop->icversion_data[j].major; + icmsg_minor = negop->icversion_data[j].minor; + found_match = true; + break; + } + } + + if (found_match) + break; + } + + /* + * Respond with the framework and service + * version numbers we can support. + */ + +fw_error: + if (!found_match) { + negop->icframe_vercnt = 0; + negop->icmsg_vercnt = 0; + } else { + negop->icframe_vercnt = 1; + negop->icmsg_vercnt = 1; + } + + if (nego_fw_version) + *nego_fw_version = (icframe_major << 16) | icframe_minor; + + if (nego_srv_version) + *nego_srv_version = (icmsg_major << 16) | icmsg_minor; + + negop->icversion_data[0].major = icframe_major; + negop->icversion_data[0].minor = icframe_minor; + negop->icversion_data[1].major = icmsg_major; + negop->icversion_data[1].minor = icmsg_minor; + return found_match; +} + +EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp); + +/* + * alloc_channel - Allocate and initialize a vmbus channel object + */ +static struct vmbus_channel *alloc_channel(void) +{ + struct vmbus_channel *channel; + + channel = kzalloc(sizeof(*channel), GFP_ATOMIC); + if (!channel) + return NULL; + + spin_lock_init(&channel->sched_lock); + init_completion(&channel->rescind_event); + + INIT_LIST_HEAD(&channel->sc_list); + + tasklet_init(&channel->callback_event, + vmbus_on_event, (unsigned long)channel); + + hv_ringbuffer_pre_init(channel); + + return channel; +} + +/* + * free_channel - Release the resources used by the vmbus channel object + */ +static void free_channel(struct vmbus_channel *channel) +{ + tasklet_kill(&channel->callback_event); + vmbus_remove_channel_attr_group(channel); + + kobject_put(&channel->kobj); +} + +void vmbus_channel_map_relid(struct vmbus_channel *channel) +{ + if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS)) + return; + /* + * The mapping of the channel's relid is visible from the CPUs that + * execute vmbus_chan_sched() by the time that vmbus_chan_sched() will + * execute: + * + * (a) In the "normal (i.e., not resuming from hibernation)" path, + * the full barrier in virt_store_mb() guarantees that the store + * is propagated to all CPUs before the add_channel_work work + * is queued. In turn, add_channel_work is queued before the + * channel's ring buffer is allocated/initialized and the + * OPENCHANNEL message for the channel is sent in vmbus_open(). + * Hyper-V won't start sending the interrupts for the channel + * before the OPENCHANNEL message is acked. The memory barrier + * in vmbus_chan_sched() -> sync_test_and_clear_bit() ensures + * that vmbus_chan_sched() must find the channel's relid in + * recv_int_page before retrieving the channel pointer from the + * array of channels. + * + * (b) In the "resuming from hibernation" path, the virt_store_mb() + * guarantees that the store is propagated to all CPUs before + * the VMBus connection is marked as ready for the resume event + * (cf. check_ready_for_resume_event()). The interrupt handler + * of the VMBus driver and vmbus_chan_sched() can not run before + * vmbus_bus_resume() has completed execution (cf. resume_noirq). + */ + virt_store_mb( + vmbus_connection.channels[channel->offermsg.child_relid], + channel); +} + +void vmbus_channel_unmap_relid(struct vmbus_channel *channel) +{ + if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS)) + return; + WRITE_ONCE( + vmbus_connection.channels[channel->offermsg.child_relid], + NULL); +} + +static void vmbus_release_relid(u32 relid) +{ + struct vmbus_channel_relid_released msg; + int ret; + + memset(&msg, 0, sizeof(struct vmbus_channel_relid_released)); + msg.child_relid = relid; + msg.header.msgtype = CHANNELMSG_RELID_RELEASED; + ret = vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released), + true); + + trace_vmbus_release_relid(&msg, ret); +} + +void hv_process_channel_removal(struct vmbus_channel *channel) +{ + lockdep_assert_held(&vmbus_connection.channel_mutex); + BUG_ON(!channel->rescind); + + /* + * hv_process_channel_removal() could find INVALID_RELID only for + * hv_sock channels. See the inline comments in vmbus_onoffer(). + */ + WARN_ON(channel->offermsg.child_relid == INVALID_RELID && + !is_hvsock_channel(channel)); + + /* + * Upon suspend, an in-use hv_sock channel is removed from the array of + * channels and the relid is invalidated. After hibernation, when the + * user-space appplication destroys the channel, it's unnecessary and + * unsafe to remove the channel from the array of channels. See also + * the inline comments before the call of vmbus_release_relid() below. + */ + if (channel->offermsg.child_relid != INVALID_RELID) + vmbus_channel_unmap_relid(channel); + + if (channel->primary_channel == NULL) + list_del(&channel->listentry); + else + list_del(&channel->sc_list); + + /* + * If this is a "perf" channel, updates the hv_numa_map[] masks so that + * init_vp_index() can (re-)use the CPU. + */ + if (hv_is_perf_channel(channel)) + hv_clear_alloced_cpu(channel->target_cpu); + + /* + * 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); +} + +void vmbus_free_channels(void) +{ + struct vmbus_channel *channel, *tmp; + + list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list, + listentry) { + /* hv_process_channel_removal() needs this */ + channel->rescind = true; + + vmbus_device_unregister(channel->device_obj); + } +} + +/* Note: the function can run concurrently for primary/sub channels. */ +static void vmbus_add_channel_work(struct work_struct *work) +{ + struct vmbus_channel *newchannel = + container_of(work, struct vmbus_channel, add_channel_work); + struct vmbus_channel *primary_channel = newchannel->primary_channel; + int ret; + + /* + * This state is used to indicate a successful open + * so that when we do close the channel normally, we + * can cleanup properly. + */ + newchannel->state = CHANNEL_OPEN_STATE; + + if (primary_channel != NULL) { + /* newchannel is a sub-channel. */ + struct hv_device *dev = primary_channel->device_obj; + + if (vmbus_add_channel_kobj(dev, newchannel)) + goto err_deq_chan; + + if (primary_channel->sc_creation_callback != NULL) + primary_channel->sc_creation_callback(newchannel); + + newchannel->probe_done = true; + return; + } + + /* + * Start the process of binding the primary channel to the driver + */ + newchannel->device_obj = vmbus_device_create( + &newchannel->offermsg.offer.if_type, + &newchannel->offermsg.offer.if_instance, + newchannel); + if (!newchannel->device_obj) + goto err_deq_chan; + + newchannel->device_obj->device_id = newchannel->device_id; + /* + * Add the new device to the bus. This will kick off device-driver + * binding which eventually invokes the device driver's AddDevice() + * method. + * + * If vmbus_device_register() fails, the 'device_obj' is freed in + * vmbus_device_release() as called by device_unregister() in the + * error path of vmbus_device_register(). In the outside error + * path, there's no need to free it. + */ + ret = vmbus_device_register(newchannel->device_obj); + + if (ret != 0) { + pr_err("unable to add child device object (relid %d)\n", + newchannel->offermsg.child_relid); + goto err_deq_chan; + } + + newchannel->probe_done = true; + return; + +err_deq_chan: + mutex_lock(&vmbus_connection.channel_mutex); + + /* + * We need to set the flag, otherwise + * vmbus_onoffer_rescind() can be blocked. + */ + newchannel->probe_done = true; + + if (primary_channel == NULL) + list_del(&newchannel->listentry); + else + list_del(&newchannel->sc_list); + + /* vmbus_process_offer() has mapped the channel. */ + vmbus_channel_unmap_relid(newchannel); + + mutex_unlock(&vmbus_connection.channel_mutex); + + vmbus_release_relid(newchannel->offermsg.child_relid); + + free_channel(newchannel); +} + +/* + * vmbus_process_offer - Process the offer by creating a channel/device + * associated with this offer + */ +static void vmbus_process_offer(struct vmbus_channel *newchannel) +{ + struct vmbus_channel *channel; + struct workqueue_struct *wq; + bool fnew = true; + + /* + * Synchronize vmbus_process_offer() and CPU hotplugging: + * + * CPU1 CPU2 + * + * [vmbus_process_offer()] [Hot removal of the CPU] + * + * CPU_READ_LOCK CPUS_WRITE_LOCK + * LOAD cpu_online_mask SEARCH chn_list + * STORE target_cpu LOAD target_cpu + * INSERT chn_list STORE cpu_online_mask + * CPUS_READ_UNLOCK CPUS_WRITE_UNLOCK + * + * Forbids: CPU1's LOAD from *not* seing CPU2's STORE && + * CPU2's SEARCH from *not* seeing CPU1's INSERT + * + * Forbids: CPU2's SEARCH from seeing CPU1's INSERT && + * CPU2's LOAD from *not* seing CPU1's STORE + */ + cpus_read_lock(); + + /* + * Serializes the modifications of the chn_list list as well as + * the accesses to next_numa_node_id in init_vp_index(). + */ + mutex_lock(&vmbus_connection.channel_mutex); + + init_vp_index(newchannel); + + /* Remember the channels that should be cleaned up upon suspend. */ + if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel)) + atomic_inc(&vmbus_connection.nr_chan_close_on_suspend); + + /* + * Now that we have acquired the channel_mutex, + * we can release the potentially racing rescind thread. + */ + atomic_dec(&vmbus_connection.offer_in_progress); + + list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { + if (guid_equal(&channel->offermsg.offer.if_type, + &newchannel->offermsg.offer.if_type) && + guid_equal(&channel->offermsg.offer.if_instance, + &newchannel->offermsg.offer.if_instance)) { + fnew = false; + break; + } + } + + if (fnew) { + list_add_tail(&newchannel->listentry, + &vmbus_connection.chn_list); + } else { + /* + * Check to see if this is a valid sub-channel. + */ + if (newchannel->offermsg.offer.sub_channel_index == 0) { + mutex_unlock(&vmbus_connection.channel_mutex); + cpus_read_unlock(); + /* + * Don't call free_channel(), because newchannel->kobj + * is not initialized yet. + */ + kfree(newchannel); + WARN_ON_ONCE(1); + return; + } + /* + * Process the sub-channel. + */ + newchannel->primary_channel = channel; + list_add_tail(&newchannel->sc_list, &channel->sc_list); + } + + vmbus_channel_map_relid(newchannel); + + mutex_unlock(&vmbus_connection.channel_mutex); + cpus_read_unlock(); + + /* + * vmbus_process_offer() mustn't call channel->sc_creation_callback() + * directly for sub-channels, because sc_creation_callback() -> + * vmbus_open() may never get the host's response to the + * OPEN_CHANNEL message (the host may rescind a channel at any time, + * e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind() + * may not wake up the vmbus_open() as it's blocked due to a non-zero + * vmbus_connection.offer_in_progress, and finally we have a deadlock. + * + * The above is also true for primary channels, if the related device + * drivers use sync probing mode by default. + * + * And, usually the handling of primary channels and sub-channels can + * depend on each other, so we should offload them to different + * workqueues to avoid possible deadlock, e.g. in sync-probing mode, + * NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() -> + * rtnl_lock(), and causes deadlock: the former gets the rtnl_lock + * and waits for all the sub-channels to appear, but the latter + * can't get the rtnl_lock and this blocks the handling of + * sub-channels. + */ + INIT_WORK(&newchannel->add_channel_work, vmbus_add_channel_work); + wq = fnew ? vmbus_connection.handle_primary_chan_wq : + vmbus_connection.handle_sub_chan_wq; + queue_work(wq, &newchannel->add_channel_work); +} + +/* + * We use this state to statically distribute the channel interrupt load. + */ +static int next_numa_node_id; + +/* + * Starting with Win8, we can statically distribute the incoming + * channel interrupt load by binding a channel to VCPU. + * + * For pre-win8 hosts or non-performance critical channels we assign the + * VMBUS_CONNECT_CPU. + * + * Starting with win8, performance critical channels will be distributed + * evenly among all the available NUMA nodes. Once the node is assigned, + * we will assign the CPU based on a simple round robin scheme. + */ +static void init_vp_index(struct vmbus_channel *channel) +{ + bool perf_chn = hv_is_perf_channel(channel); + cpumask_var_t available_mask; + struct cpumask *alloced_mask; + u32 target_cpu; + int numa_node; + + if ((vmbus_proto_version == VERSION_WS2008) || + (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) || + !alloc_cpumask_var(&available_mask, GFP_KERNEL)) { + /* + * Prior to win8, all channel interrupts are + * delivered on VMBUS_CONNECT_CPU. + * Also if the channel is not a performance critical + * channel, bind it to VMBUS_CONNECT_CPU. + * In case alloc_cpumask_var() fails, bind it to + * VMBUS_CONNECT_CPU. + */ + channel->target_cpu = VMBUS_CONNECT_CPU; + if (perf_chn) + hv_set_alloced_cpu(VMBUS_CONNECT_CPU); + return; + } + + while (true) { + numa_node = next_numa_node_id++; + if (numa_node == nr_node_ids) { + next_numa_node_id = 0; + continue; + } + if (cpumask_empty(cpumask_of_node(numa_node))) + continue; + break; + } + alloced_mask = &hv_context.hv_numa_map[numa_node]; + + if (cpumask_weight(alloced_mask) == + cpumask_weight(cpumask_of_node(numa_node))) { + /* + * We have cycled through all the CPUs in the node; + * reset the alloced map. + */ + cpumask_clear(alloced_mask); + } + + cpumask_xor(available_mask, alloced_mask, cpumask_of_node(numa_node)); + + target_cpu = cpumask_first(available_mask); + cpumask_set_cpu(target_cpu, alloced_mask); + + channel->target_cpu = target_cpu; + + free_cpumask_var(available_mask); +} + +#define UNLOAD_DELAY_UNIT_MS 10 /* 10 milliseconds */ +#define UNLOAD_WAIT_MS (100*1000) /* 100 seconds */ +#define UNLOAD_WAIT_LOOPS (UNLOAD_WAIT_MS/UNLOAD_DELAY_UNIT_MS) +#define UNLOAD_MSG_MS (5*1000) /* Every 5 seconds */ +#define UNLOAD_MSG_LOOPS (UNLOAD_MSG_MS/UNLOAD_DELAY_UNIT_MS) + +static void vmbus_wait_for_unload(void) +{ + int cpu; + void *page_addr; + struct hv_message *msg; + struct vmbus_channel_message_header *hdr; + u32 message_type, i; + + /* + * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was + * used for initial contact or to CPU0 depending on host version. When + * we're crashing on a different CPU let's hope that IRQ handler on + * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still + * functional and vmbus_unload_response() will complete + * vmbus_connection.unload_event. If not, the last thing we can do is + * read message pages for all CPUs directly. + * + * Wait up to 100 seconds since an Azure host must writeback any dirty + * data in its disk cache before the VMbus UNLOAD request will + * complete. This flushing has been empirically observed to take up + * to 50 seconds in cases with a lot of dirty data, so allow additional + * leeway and for inaccuracies in mdelay(). But eventually time out so + * that the panic path can't get hung forever in case the response + * message isn't seen. + */ + for (i = 1; i <= UNLOAD_WAIT_LOOPS; i++) { + if (completion_done(&vmbus_connection.unload_event)) + goto completed; + + for_each_present_cpu(cpu) { + struct hv_per_cpu_context *hv_cpu + = per_cpu_ptr(hv_context.cpu_context, cpu); + + /* + * In a CoCo VM the synic_message_page is not allocated + * in hv_synic_alloc(). Instead it is set/cleared in + * hv_synic_enable_regs() and hv_synic_disable_regs() + * such that it is set only when the CPU is online. If + * not all present CPUs are online, the message page + * might be NULL, so skip such CPUs. + */ + page_addr = hv_cpu->synic_message_page; + if (!page_addr) + continue; + + msg = (struct hv_message *)page_addr + + VMBUS_MESSAGE_SINT; + + message_type = READ_ONCE(msg->header.message_type); + if (message_type == HVMSG_NONE) + continue; + + hdr = (struct vmbus_channel_message_header *) + msg->u.payload; + + if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE) + complete(&vmbus_connection.unload_event); + + vmbus_signal_eom(msg, message_type); + } + + /* + * Give a notice periodically so someone watching the + * serial output won't think it is completely hung. + */ + if (!(i % UNLOAD_MSG_LOOPS)) + pr_notice("Waiting for VMBus UNLOAD to complete\n"); + + mdelay(UNLOAD_DELAY_UNIT_MS); + } + pr_err("Continuing even though VMBus UNLOAD did not complete\n"); + +completed: + /* + * We're crashing and already got the UNLOAD_RESPONSE, cleanup all + * maybe-pending messages on all CPUs to be able to receive new + * messages after we reconnect. + */ + for_each_present_cpu(cpu) { + struct hv_per_cpu_context *hv_cpu + = per_cpu_ptr(hv_context.cpu_context, cpu); + + page_addr = hv_cpu->synic_message_page; + if (!page_addr) + continue; + + msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT; + msg->header.message_type = HVMSG_NONE; + } +} + +/* + * vmbus_unload_response - Handler for the unload response. + */ +static void vmbus_unload_response(struct vmbus_channel_message_header *hdr) +{ + /* + * This is a global event; just wakeup the waiting thread. + * Once we successfully unload, we can cleanup the monitor state. + */ + complete(&vmbus_connection.unload_event); +} + +void vmbus_initiate_unload(bool crash) +{ + struct vmbus_channel_message_header hdr; + + if (xchg(&vmbus_connection.conn_state, DISCONNECTED) == DISCONNECTED) + return; + + /* Pre-Win2012R2 hosts don't support reconnect */ + if (vmbus_proto_version < VERSION_WIN8_1) + return; + + init_completion(&vmbus_connection.unload_event); + memset(&hdr, 0, sizeof(struct vmbus_channel_message_header)); + hdr.msgtype = CHANNELMSG_UNLOAD; + vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header), + !crash); + + /* + * vmbus_initiate_unload() is also called on crash and the crash can be + * happening in an interrupt context, where scheduling is impossible. + */ + if (!crash) + wait_for_completion(&vmbus_connection.unload_event); + else + 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; + channel->device_id = hv_get_dev_type(channel); +} + +/* + * find_primary_channel_by_offer - Get the channel object given the new offer. + * This is only used in the resume path of hibernation. + */ +static struct vmbus_channel * +find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer) +{ + struct vmbus_channel *channel = NULL, *iter; + const guid_t *inst1, *inst2; + + /* Ignore sub-channel offers. */ + if (offer->offer.sub_channel_index != 0) + return NULL; + + mutex_lock(&vmbus_connection.channel_mutex); + + list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) { + inst1 = &iter->offermsg.offer.if_instance; + inst2 = &offer->offer.if_instance; + + if (guid_equal(inst1, inst2)) { + channel = iter; + break; + } + } + + mutex_unlock(&vmbus_connection.channel_mutex); + + return channel; +} + +/* + * vmbus_onoffer - Handler for channel offers from vmbus in parent partition. + * + */ +static void vmbus_onoffer(struct vmbus_channel_message_header *hdr) +{ + struct vmbus_channel_offer_channel *offer; + struct vmbus_channel *oldchannel, *newchannel; + size_t offer_sz; + + offer = (struct vmbus_channel_offer_channel *)hdr; + + trace_vmbus_onoffer(offer); + + oldchannel = find_primary_channel_by_offer(offer); + + if (oldchannel != NULL) { + /* + * 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. + */ + + /* + * { Initially: channel relid = INVALID_RELID, + * channels[valid_relid] = NULL } + * + * CPU1 CPU2 + * + * [vmbus_onoffer()] [vmbus_device_release()] + * + * LOCK channel_mutex LOCK channel_mutex + * STORE channel relid = valid_relid LOAD r1 = channel relid + * MAP_RELID channel if (r1 != INVALID_RELID) + * UNLOCK channel_mutex UNMAP_RELID channel + * UNLOCK channel_mutex + * + * Forbids: r1 == valid_relid && + * channels[valid_relid] == channel + * + * Note. r1 can be INVALID_RELID only for an hv_sock channel. + * None of the hv_sock channels which were present before the + * suspend are re-offered upon the resume. See the WARN_ON() + * in hv_process_channel_removal(). + */ + mutex_lock(&vmbus_connection.channel_mutex); + + atomic_dec(&vmbus_connection.offer_in_progress); + + 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) { + /* + * 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, 16, 4, + &oldchannel->offermsg, offer_sz, + 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); + } + + /* Add the channel back to the array of channels. */ + vmbus_channel_map_relid(oldchannel); + check_ready_for_resume_event(); + + mutex_unlock(&vmbus_connection.channel_mutex); + return; + } + + /* Allocate the channel object and save this offer. */ + newchannel = alloc_channel(); + if (!newchannel) { + vmbus_release_relid(offer->child_relid); + atomic_dec(&vmbus_connection.offer_in_progress); + pr_err("Unable to allocate channel object\n"); + return; + } + + vmbus_setup_channel_state(newchannel, offer); + + vmbus_process_offer(newchannel); +} + +static void check_ready_for_suspend_event(void) +{ + /* + * If all the sub-channels or hv_sock channels have been cleaned up, + * then it's safe to suspend. + */ + if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend)) + complete(&vmbus_connection.ready_for_suspend_event); +} + +/* + * vmbus_onoffer_rescind - Rescind offer handler. + * + * We queue a work item to process this offer synchronously + */ +static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr) +{ + struct vmbus_channel_rescind_offer *rescind; + struct vmbus_channel *channel; + struct device *dev; + bool clean_up_chan_for_suspend; + + rescind = (struct vmbus_channel_rescind_offer *)hdr; + + trace_vmbus_onoffer_rescind(rescind); + + /* + * The offer msg and the corresponding rescind msg + * from the host are guranteed to be ordered - + * offer comes in first and then the rescind. + * Since we process these events in work elements, + * and with preemption, we may end up processing + * the events out of order. We rely on the synchronization + * provided by offer_in_progress and by channel_mutex for + * ordering these events: + * + * { Initially: offer_in_progress = 1 } + * + * CPU1 CPU2 + * + * [vmbus_onoffer()] [vmbus_onoffer_rescind()] + * + * LOCK channel_mutex WAIT_ON offer_in_progress == 0 + * DECREMENT offer_in_progress LOCK channel_mutex + * STORE channels[] LOAD channels[] + * UNLOCK channel_mutex UNLOCK channel_mutex + * + * Forbids: CPU2's LOAD from *not* seeing CPU1's STORE + */ + + while (atomic_read(&vmbus_connection.offer_in_progress) != 0) { + /* + * We wait here until any channel offer is currently + * being processed. + */ + msleep(1); + } + + mutex_lock(&vmbus_connection.channel_mutex); + channel = relid2channel(rescind->child_relid); + mutex_unlock(&vmbus_connection.channel_mutex); + + if (channel == NULL) { + /* + * We failed in processing the offer message; + * we would have cleaned up the relid in that + * failure path. + */ + return; + } + + clean_up_chan_for_suspend = is_hvsock_channel(channel) || + is_sub_channel(channel); + /* + * Before setting channel->rescind in vmbus_rescind_cleanup(), we + * should make sure the channel callback is not running any more. + */ + vmbus_reset_channel_cb(channel); + + /* + * Now wait for offer handling to complete. + */ + vmbus_rescind_cleanup(channel); + while (READ_ONCE(channel->probe_done) == false) { + /* + * We wait here until any channel offer is currently + * being processed. + */ + msleep(1); + } + + /* + * At this point, the rescind handling can proceed safely. + */ + + if (channel->device_obj) { + if (channel->chn_rescind_callback) { + channel->chn_rescind_callback(channel); + + if (clean_up_chan_for_suspend) + check_ready_for_suspend_event(); + + return; + } + /* + * We will have to unregister this device from the + * driver core. + */ + dev = get_device(&channel->device_obj->device); + if (dev) { + vmbus_device_unregister(channel->device_obj); + put_device(dev); + } + } else if (channel->primary_channel != NULL) { + /* + * Sub-channel is being rescinded. Following is the channel + * close sequence when initiated from the driveri (refer to + * vmbus_close() for details): + * 1. Close all sub-channels first + * 2. Then close the primary channel. + */ + mutex_lock(&vmbus_connection.channel_mutex); + if (channel->state == CHANNEL_OPEN_STATE) { + /* + * The channel is currently not open; + * it is safe for us to cleanup the channel. + */ + hv_process_channel_removal(channel); + } else { + complete(&channel->rescind_event); + } + mutex_unlock(&vmbus_connection.channel_mutex); + } + + /* The "channel" may have been freed. Do not access it any longer. */ + + if (clean_up_chan_for_suspend) + check_ready_for_suspend_event(); +} + +void vmbus_hvsock_device_unregister(struct vmbus_channel *channel) +{ + BUG_ON(!is_hvsock_channel(channel)); + + /* We always get a rescind msg when a connection is closed. */ + while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind)) + msleep(1); + + vmbus_device_unregister(channel->device_obj); +} +EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister); + + +/* + * vmbus_onoffers_delivered - + * This is invoked when all offers have been delivered. + * + * Nothing to do here. + */ +static void vmbus_onoffers_delivered( + struct vmbus_channel_message_header *hdr) +{ +} + +/* + * vmbus_onopen_result - Open result handler. + * + * This is invoked when we received a response to our channel open request. + * Find the matching request, copy the response and signal the requesting + * thread. + */ +static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr) +{ + struct vmbus_channel_open_result *result; + struct vmbus_channel_msginfo *msginfo; + struct vmbus_channel_message_header *requestheader; + struct vmbus_channel_open_channel *openmsg; + unsigned long flags; + + result = (struct vmbus_channel_open_result *)hdr; + + trace_vmbus_onopen_result(result); + + /* + * Find the open msg, copy the result and signal/unblock the wait event + */ + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + + list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, + msglistentry) { + requestheader = + (struct vmbus_channel_message_header *)msginfo->msg; + + if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) { + openmsg = + (struct vmbus_channel_open_channel *)msginfo->msg; + if (openmsg->child_relid == result->child_relid && + openmsg->openid == result->openid) { + memcpy(&msginfo->response.open_result, + result, + sizeof( + struct vmbus_channel_open_result)); + complete(&msginfo->waitevent); + break; + } + } + } + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +} + +/* + * vmbus_ongpadl_created - GPADL created handler. + * + * This is invoked when we received a response to our gpadl create request. + * Find the matching request, copy the response and signal the requesting + * thread. + */ +static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr) +{ + struct vmbus_channel_gpadl_created *gpadlcreated; + struct vmbus_channel_msginfo *msginfo; + struct vmbus_channel_message_header *requestheader; + struct vmbus_channel_gpadl_header *gpadlheader; + unsigned long flags; + + gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr; + + trace_vmbus_ongpadl_created(gpadlcreated); + + /* + * Find the establish msg, copy the result and signal/unblock the wait + * event + */ + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + + list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, + msglistentry) { + requestheader = + (struct vmbus_channel_message_header *)msginfo->msg; + + if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) { + gpadlheader = + (struct vmbus_channel_gpadl_header *)requestheader; + + if ((gpadlcreated->child_relid == + gpadlheader->child_relid) && + (gpadlcreated->gpadl == gpadlheader->gpadl)) { + memcpy(&msginfo->response.gpadl_created, + gpadlcreated, + sizeof( + struct vmbus_channel_gpadl_created)); + complete(&msginfo->waitevent); + break; + } + } + } + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +} + +/* + * vmbus_ongpadl_torndown - GPADL torndown handler. + * + * This is invoked when we received a response to our gpadl teardown request. + * Find the matching request, copy the response and signal the requesting + * thread. + */ +static void vmbus_ongpadl_torndown( + struct vmbus_channel_message_header *hdr) +{ + struct vmbus_channel_gpadl_torndown *gpadl_torndown; + struct vmbus_channel_msginfo *msginfo; + struct vmbus_channel_message_header *requestheader; + struct vmbus_channel_gpadl_teardown *gpadl_teardown; + unsigned long flags; + + gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr; + + trace_vmbus_ongpadl_torndown(gpadl_torndown); + + /* + * Find the open msg, copy the result and signal/unblock the wait event + */ + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + + list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, + msglistentry) { + requestheader = + (struct vmbus_channel_message_header *)msginfo->msg; + + if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) { + gpadl_teardown = + (struct vmbus_channel_gpadl_teardown *)requestheader; + + if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) { + memcpy(&msginfo->response.gpadl_torndown, + gpadl_torndown, + sizeof( + struct vmbus_channel_gpadl_torndown)); + complete(&msginfo->waitevent); + break; + } + } + } + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +} + +/* + * vmbus_onversion_response - Version response handler + * + * This is invoked when we received a response to our initiate contact request. + * Find the matching request, copy the response and signal the requesting + * thread. + */ +static void vmbus_onversion_response( + struct vmbus_channel_message_header *hdr) +{ + struct vmbus_channel_msginfo *msginfo; + struct vmbus_channel_message_header *requestheader; + struct vmbus_channel_version_response *version_response; + unsigned long flags; + + version_response = (struct vmbus_channel_version_response *)hdr; + + trace_vmbus_onversion_response(version_response); + + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); + + list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, + msglistentry) { + requestheader = + (struct vmbus_channel_message_header *)msginfo->msg; + + if (requestheader->msgtype == + CHANNELMSG_INITIATE_CONTACT) { + memcpy(&msginfo->response.version_response, + version_response, + sizeof(struct vmbus_channel_version_response)); + complete(&msginfo->waitevent); + } + } + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); +} + +/* Channel message dispatch table */ +const struct vmbus_channel_message_table_entry +channel_message_table[CHANNELMSG_COUNT] = { + { CHANNELMSG_INVALID, 0, NULL, 0}, + { CHANNELMSG_OFFERCHANNEL, 0, vmbus_onoffer, + sizeof(struct vmbus_channel_offer_channel)}, + { CHANNELMSG_RESCIND_CHANNELOFFER, 0, vmbus_onoffer_rescind, + sizeof(struct vmbus_channel_rescind_offer) }, + { CHANNELMSG_REQUESTOFFERS, 0, NULL, 0}, + { CHANNELMSG_ALLOFFERS_DELIVERED, 1, vmbus_onoffers_delivered, 0}, + { CHANNELMSG_OPENCHANNEL, 0, NULL, 0}, + { CHANNELMSG_OPENCHANNEL_RESULT, 1, vmbus_onopen_result, + sizeof(struct vmbus_channel_open_result)}, + { CHANNELMSG_CLOSECHANNEL, 0, NULL, 0}, + { CHANNELMSG_GPADL_HEADER, 0, NULL, 0}, + { CHANNELMSG_GPADL_BODY, 0, NULL, 0}, + { CHANNELMSG_GPADL_CREATED, 1, vmbus_ongpadl_created, + sizeof(struct vmbus_channel_gpadl_created)}, + { CHANNELMSG_GPADL_TEARDOWN, 0, NULL, 0}, + { CHANNELMSG_GPADL_TORNDOWN, 1, vmbus_ongpadl_torndown, + sizeof(struct vmbus_channel_gpadl_torndown) }, + { CHANNELMSG_RELID_RELEASED, 0, NULL, 0}, + { CHANNELMSG_INITIATE_CONTACT, 0, NULL, 0}, + { CHANNELMSG_VERSION_RESPONSE, 1, vmbus_onversion_response, + sizeof(struct vmbus_channel_version_response)}, + { CHANNELMSG_UNLOAD, 0, NULL, 0}, + { CHANNELMSG_UNLOAD_RESPONSE, 1, vmbus_unload_response, 0}, + { CHANNELMSG_18, 0, NULL, 0}, + { CHANNELMSG_19, 0, NULL, 0}, + { CHANNELMSG_20, 0, NULL, 0}, + { CHANNELMSG_TL_CONNECT_REQUEST, 0, NULL, 0}, + { CHANNELMSG_MODIFYCHANNEL, 0, NULL, 0}, + { CHANNELMSG_TL_CONNECT_RESULT, 0, NULL, 0}, +}; + +/* + * vmbus_onmessage - Handler for channel protocol messages. + * + * This is invoked in the vmbus worker thread context. + */ +void vmbus_onmessage(struct vmbus_channel_message_header *hdr) +{ + trace_vmbus_on_message(hdr); + + /* + * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go + * out of bound and the message_handler pointer can not be NULL. + */ + channel_message_table[hdr->msgtype].message_handler(hdr); +} + +/* + * vmbus_request_offers - Send a request to get all our pending offers. + */ +int vmbus_request_offers(void) +{ + struct vmbus_channel_message_header *msg; + struct vmbus_channel_msginfo *msginfo; + int ret; + + msginfo = kmalloc(sizeof(*msginfo) + + sizeof(struct vmbus_channel_message_header), + GFP_KERNEL); + if (!msginfo) + return -ENOMEM; + + msg = (struct vmbus_channel_message_header *)msginfo->msg; + + msg->msgtype = CHANNELMSG_REQUESTOFFERS; + + ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header), + true); + + trace_vmbus_request_offers(ret); + + if (ret != 0) { + pr_err("Unable to request offers - %d\n", ret); + + goto cleanup; + } + +cleanup: + kfree(msginfo); + + return ret; +} + +static void invoke_sc_cb(struct vmbus_channel *primary_channel) +{ + struct list_head *cur, *tmp; + struct vmbus_channel *cur_channel; + + if (primary_channel->sc_creation_callback == NULL) + return; + + list_for_each_safe(cur, tmp, &primary_channel->sc_list) { + cur_channel = list_entry(cur, struct vmbus_channel, sc_list); + + primary_channel->sc_creation_callback(cur_channel); + } +} + +void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel, + void (*sc_cr_cb)(struct vmbus_channel *new_sc)) +{ + primary_channel->sc_creation_callback = sc_cr_cb; +} +EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback); + +bool vmbus_are_subchannels_present(struct vmbus_channel *primary) +{ + bool ret; + + ret = !list_empty(&primary->sc_list); + + if (ret) { + /* + * Invoke the callback on sub-channel creation. + * This will present a uniform interface to the + * clients. + */ + invoke_sc_cb(primary); + } + + return ret; +} +EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present); + +void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel, + void (*chn_rescind_cb)(struct vmbus_channel *)) +{ + channel->chn_rescind_callback = chn_rescind_cb; +} +EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback); |