diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-03 15:00:05 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-03 15:00:05 -0700 |
commit | 6b2591c21273ebf65c13dae5d260ce88f0f197dd (patch) | |
tree | 9d19b72d7d9461c210b8f38e57720268bf85c96f /drivers/hv/vmbus_drv.c | |
parent | f1e455352b6f503532eb3637d0a6d991895e7856 (diff) | |
parent | afaa33da08abd10be8978781d7c99a9e67d2bbff (diff) | |
download | linux-stable-6b2591c21273ebf65c13dae5d260ce88f0f197dd.tar.gz linux-stable-6b2591c21273ebf65c13dae5d260ce88f0f197dd.tar.bz2 linux-stable-6b2591c21273ebf65c13dae5d260ce88f0f197dd.zip |
Merge tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyper-v updates from Wei Liu:
- a series from Andrea to support channel reassignment
- a series from Vitaly to clean up Vmbus message handling
- a series from Michael to clean up and augment hyperv-tlfs.h
- patches from Andy to clean up GUID usage in Hyper-V code
- a few other misc patches
* tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (29 commits)
Drivers: hv: vmbus: Resolve more races involving init_vp_index()
Drivers: hv: vmbus: Resolve race between init_vp_index() and CPU hotplug
vmbus: Replace zero-length array with flexible-array
Driver: hv: vmbus: drop a no long applicable comment
hyper-v: Switch to use UUID types directly
hyper-v: Replace open-coded variant of %*phN specifier
hyper-v: Supply GUID pointer to printf() like functions
hyper-v: Use UUID API for exporting the GUID (part 2)
asm-generic/hyperv: Add definitions for Get/SetVpRegister hypercalls
x86/hyperv: Split hyperv-tlfs.h into arch dependent and independent files
x86/hyperv: Remove HV_PROCESSOR_POWER_STATE #defines
KVM: x86: hyperv: Remove duplicate definitions of Reference TSC Page
drivers: hv: remove redundant assignment to pointer primary_channel
scsi: storvsc: Re-init stor_chns when a channel interrupt is re-assigned
Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type
Drivers: hv: vmbus: Synchronize init_vp_index() vs. CPU hotplug
Drivers: hv: vmbus: Remove the unused HV_LOCALIZED channel affinity logic
PCI: hv: Prepare hv_compose_msi_msg() for the VMBus-channel-interrupt-to-vCPU reassignment functionality
Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal
hv_utils: Always execute the fcopy and vss callbacks in a tasklet
...
Diffstat (limited to 'drivers/hv/vmbus_drv.c')
-rw-r--r-- | drivers/hv/vmbus_drv.c | 314 |
1 files changed, 243 insertions, 71 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index e06c6b9555cf..9147ee9d5f7d 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -117,14 +117,6 @@ static int vmbus_exists(void) return 0; } -#define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2) -static void print_alias_name(struct hv_device *hv_dev, char *alias_name) -{ - int i; - for (i = 0; i < VMBUS_ALIAS_LEN; i += 2) - sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]); -} - static u8 channel_monitor_group(const struct vmbus_channel *channel) { return (u8)channel->offermsg.monitorid / 32; @@ -201,7 +193,7 @@ static ssize_t class_id_show(struct device *dev, if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "{%pUl}\n", - hv_dev->channel->offermsg.offer.if_type.b); + &hv_dev->channel->offermsg.offer.if_type); } static DEVICE_ATTR_RO(class_id); @@ -213,7 +205,7 @@ static ssize_t device_id_show(struct device *dev, if (!hv_dev->channel) return -ENODEV; return sprintf(buf, "{%pUl}\n", - hv_dev->channel->offermsg.offer.if_instance.b); + &hv_dev->channel->offermsg.offer.if_instance); } static DEVICE_ATTR_RO(device_id); @@ -221,10 +213,8 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *dev_attr, char *buf) { struct hv_device *hv_dev = device_to_hv_device(dev); - char alias_name[VMBUS_ALIAS_LEN + 1]; - print_alias_name(hv_dev, alias_name); - return sprintf(buf, "vmbus:%s\n", alias_name); + return sprintf(buf, "vmbus:%*phN\n", UUID_SIZE, &hv_dev->dev_type); } static DEVICE_ATTR_RO(modalias); @@ -693,12 +683,9 @@ __ATTRIBUTE_GROUPS(vmbus_dev); static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env) { struct hv_device *dev = device_to_hv_device(device); - int ret; - char alias_name[VMBUS_ALIAS_LEN + 1]; + const char *format = "MODALIAS=vmbus:%*phN"; - print_alias_name(dev, alias_name); - ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name); - return ret; + return add_uevent_var(env, format, UUID_SIZE, &dev->dev_type); } static const struct hv_vmbus_device_id * @@ -1033,7 +1020,10 @@ static struct bus_type hv_bus = { struct onmessage_work_context { struct work_struct work; - struct hv_message msg; + struct { + struct hv_message_header header; + u8 payload[]; + } msg; }; static void vmbus_onmessage_work(struct work_struct *work) @@ -1046,7 +1036,8 @@ static void vmbus_onmessage_work(struct work_struct *work) ctx = container_of(work, struct onmessage_work_context, work); - vmbus_onmessage(&ctx->msg); + vmbus_onmessage((struct vmbus_channel_message_header *) + &ctx->msg.payload); kfree(ctx); } @@ -1061,6 +1052,13 @@ void vmbus_on_msg_dpc(unsigned long data) struct onmessage_work_context *ctx; u32 message_type = msg->header.message_type; + /* + * 'enum vmbus_channel_message_type' is supposed to always be 'u32' as + * it is being used in 'struct vmbus_channel_message_header' definition + * which is supposed to match hypervisor ABI. + */ + BUILD_BUG_ON(sizeof(enum vmbus_channel_message_type) != sizeof(u32)); + if (message_type == HVMSG_NONE) /* no msg */ return; @@ -1074,41 +1072,88 @@ void vmbus_on_msg_dpc(unsigned long data) goto msg_handled; } + if (msg->header.payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) { + WARN_ONCE(1, "payload size is too large (%d)\n", + msg->header.payload_size); + goto msg_handled; + } + entry = &channel_message_table[hdr->msgtype]; if (!entry->message_handler) goto msg_handled; + if (msg->header.payload_size < entry->min_payload_len) { + WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", + hdr->msgtype, msg->header.payload_size); + goto msg_handled; + } + if (entry->handler_type == VMHT_BLOCKING) { - ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC); + ctx = kmalloc(sizeof(*ctx) + msg->header.payload_size, + GFP_ATOMIC); if (ctx == NULL) return; INIT_WORK(&ctx->work, vmbus_onmessage_work); - memcpy(&ctx->msg, msg, sizeof(*msg)); + memcpy(&ctx->msg, msg, sizeof(msg->header) + + msg->header.payload_size); /* * The host can generate a rescind message while we * may still be handling the original offer. We deal with - * this condition by ensuring the processing is done on the - * same CPU. + * this condition by relying on the synchronization provided + * by offer_in_progress and by channel_mutex. See also the + * inline comments in vmbus_onoffer_rescind(). */ switch (hdr->msgtype) { case CHANNELMSG_RESCIND_CHANNELOFFER: /* * If we are handling the rescind message; * schedule the work on the global work queue. + * + * The OFFER message and the RESCIND message should + * not be handled by the same serialized work queue, + * because the OFFER handler may call vmbus_open(), + * which tries to open the channel by sending an + * OPEN_CHANNEL message to the host and waits for + * the host's response; however, if the host has + * rescinded the channel before it receives the + * OPEN_CHANNEL message, the host just silently + * ignores the OPEN_CHANNEL message; as a result, + * the guest's OFFER handler hangs for ever, if we + * handle the RESCIND message in the same serialized + * work queue: the RESCIND handler can not start to + * run before the OFFER handler finishes. */ - schedule_work_on(vmbus_connection.connect_cpu, - &ctx->work); + schedule_work(&ctx->work); break; case CHANNELMSG_OFFERCHANNEL: + /* + * The host sends the offer message of a given channel + * before sending the rescind message of the same + * channel. These messages are sent to the guest's + * connect CPU; the guest then starts processing them + * in the tasklet handler on this CPU: + * + * VMBUS_CONNECT_CPU + * + * [vmbus_on_msg_dpc()] + * atomic_inc() // CHANNELMSG_OFFERCHANNEL + * queue_work() + * ... + * [vmbus_on_msg_dpc()] + * schedule_work() // CHANNELMSG_RESCIND_CHANNELOFFER + * + * We rely on the memory-ordering properties of the + * queue_work() and schedule_work() primitives, which + * guarantee that the atomic increment will be visible + * to the CPUs which will execute the offer & rescind + * works by the time these works will start execution. + */ atomic_inc(&vmbus_connection.offer_in_progress); - queue_work_on(vmbus_connection.connect_cpu, - vmbus_connection.work_queue, - &ctx->work); - break; + fallthrough; default: queue_work(vmbus_connection.work_queue, &ctx->work); @@ -1133,10 +1178,11 @@ static void vmbus_force_channel_rescinded(struct vmbus_channel *channel) WARN_ON(!is_hvsock_channel(channel)); /* - * sizeof(*ctx) is small and the allocation should really not fail, + * Allocation size is small and the allocation should really not fail, * otherwise the state of the hv_sock connections ends up in limbo. */ - ctx = kzalloc(sizeof(*ctx), GFP_KERNEL | __GFP_NOFAIL); + ctx = kzalloc(sizeof(*ctx) + sizeof(*rescind), + GFP_KERNEL | __GFP_NOFAIL); /* * So far, these are not really used by Linux. Just set them to the @@ -1146,31 +1192,17 @@ static void vmbus_force_channel_rescinded(struct vmbus_channel *channel) ctx->msg.header.payload_size = sizeof(*rescind); /* These values are actually used by Linux. */ - rescind = (struct vmbus_channel_rescind_offer *)ctx->msg.u.payload; + rescind = (struct vmbus_channel_rescind_offer *)ctx->msg.payload; rescind->header.msgtype = CHANNELMSG_RESCIND_CHANNELOFFER; rescind->child_relid = channel->offermsg.child_relid; INIT_WORK(&ctx->work, vmbus_onmessage_work); - queue_work_on(vmbus_connection.connect_cpu, - vmbus_connection.work_queue, - &ctx->work); + queue_work(vmbus_connection.work_queue, &ctx->work); } #endif /* CONFIG_PM_SLEEP */ /* - * Direct callback for channels using other deferred processing - */ -static void vmbus_channel_isr(struct vmbus_channel *channel) -{ - void (*callback_fn)(void *); - - callback_fn = READ_ONCE(channel->onchannel_callback); - if (likely(callback_fn != NULL)) - (*callback_fn)(channel->channel_callback_context); -} - -/* * Schedule all channels with events pending */ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) @@ -1200,6 +1232,7 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) return; for_each_set_bit(relid, recv_int_page, maxbits) { + void (*callback_fn)(void *context); struct vmbus_channel *channel; if (!sync_test_and_clear_bit(relid, recv_int_page)) @@ -1209,33 +1242,54 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) if (relid == 0) continue; + /* + * Pairs with the kfree_rcu() in vmbus_chan_release(). + * Guarantees that the channel data structure doesn't + * get freed while the channel pointer below is being + * dereferenced. + */ rcu_read_lock(); /* Find channel based on relid */ - list_for_each_entry_rcu(channel, &hv_cpu->chan_list, percpu_list) { - if (channel->offermsg.child_relid != relid) - continue; + channel = relid2channel(relid); + if (channel == NULL) + goto sched_unlock_rcu; - if (channel->rescind) - continue; + if (channel->rescind) + goto sched_unlock_rcu; - trace_vmbus_chan_sched(channel); + /* + * Make sure that the ring buffer data structure doesn't get + * freed while we dereference the ring buffer pointer. Test + * for the channel's onchannel_callback being NULL within a + * sched_lock critical section. See also the inline comments + * in vmbus_reset_channel_cb(). + */ + spin_lock(&channel->sched_lock); - ++channel->interrupts; + callback_fn = channel->onchannel_callback; + if (unlikely(callback_fn == NULL)) + goto sched_unlock; - switch (channel->callback_mode) { - case HV_CALL_ISR: - vmbus_channel_isr(channel); - break; + trace_vmbus_chan_sched(channel); - case HV_CALL_BATCHED: - hv_begin_read(&channel->inbound); - /* fallthrough */ - case HV_CALL_DIRECT: - tasklet_schedule(&channel->callback_event); - } + ++channel->interrupts; + + switch (channel->callback_mode) { + case HV_CALL_ISR: + (*callback_fn)(channel->channel_callback_context); + break; + + case HV_CALL_BATCHED: + hv_begin_read(&channel->inbound); + fallthrough; + case HV_CALL_DIRECT: + tasklet_schedule(&channel->callback_event); } +sched_unlock: + spin_unlock(&channel->sched_lock); +sched_unlock_rcu: rcu_read_unlock(); } } @@ -1364,7 +1418,6 @@ static int vmbus_bus_init(void) { int ret; - /* Hypervisor initialization...setup hypercall page..etc */ ret = hv_init(); if (ret != 0) { pr_err("Unable to initialize the hypervisor - 0x%x\n", ret); @@ -1553,8 +1606,24 @@ static ssize_t vmbus_chan_attr_show(struct kobject *kobj, return attribute->show(chan, buf); } +static ssize_t vmbus_chan_attr_store(struct kobject *kobj, + struct attribute *attr, const char *buf, + size_t count) +{ + const struct vmbus_chan_attribute *attribute + = container_of(attr, struct vmbus_chan_attribute, attr); + struct vmbus_channel *chan + = container_of(kobj, struct vmbus_channel, kobj); + + if (!attribute->store) + return -EIO; + + return attribute->store(chan, buf, count); +} + static const struct sysfs_ops vmbus_chan_sysfs_ops = { .show = vmbus_chan_attr_show, + .store = vmbus_chan_attr_store, }; static ssize_t out_mask_show(struct vmbus_channel *channel, char *buf) @@ -1625,11 +1694,110 @@ static ssize_t write_avail_show(struct vmbus_channel *channel, char *buf) } static VMBUS_CHAN_ATTR_RO(write_avail); -static ssize_t show_target_cpu(struct vmbus_channel *channel, char *buf) +static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%u\n", channel->target_cpu); } -static VMBUS_CHAN_ATTR(cpu, S_IRUGO, show_target_cpu, NULL); +static ssize_t target_cpu_store(struct vmbus_channel *channel, + const char *buf, size_t count) +{ + u32 target_cpu, origin_cpu; + ssize_t ret = count; + + if (vmbus_proto_version < VERSION_WIN10_V4_1) + return -EIO; + + if (sscanf(buf, "%uu", &target_cpu) != 1) + return -EIO; + + /* Validate target_cpu for the cpumask_test_cpu() operation below. */ + if (target_cpu >= nr_cpumask_bits) + return -EINVAL; + + /* No CPUs should come up or down during this. */ + cpus_read_lock(); + + if (!cpumask_test_cpu(target_cpu, cpu_online_mask)) { + cpus_read_unlock(); + return -EINVAL; + } + + /* + * Synchronizes target_cpu_store() and channel closure: + * + * { Initially: state = CHANNEL_OPENED } + * + * CPU1 CPU2 + * + * [target_cpu_store()] [vmbus_disconnect_ring()] + * + * LOCK channel_mutex LOCK channel_mutex + * LOAD r1 = state LOAD r2 = state + * IF (r1 == CHANNEL_OPENED) IF (r2 == CHANNEL_OPENED) + * SEND MODIFYCHANNEL STORE state = CHANNEL_OPEN + * [...] SEND CLOSECHANNEL + * UNLOCK channel_mutex UNLOCK channel_mutex + * + * Forbids: r1 == r2 == CHANNEL_OPENED (i.e., CPU1's LOCK precedes + * CPU2's LOCK) && CPU2's SEND precedes CPU1's SEND + * + * Note. The host processes the channel messages "sequentially", in + * the order in which they are received on a per-partition basis. + */ + mutex_lock(&vmbus_connection.channel_mutex); + + /* + * Hyper-V will ignore MODIFYCHANNEL messages for "non-open" channels; + * avoid sending the message and fail here for such channels. + */ + if (channel->state != CHANNEL_OPENED_STATE) { + ret = -EIO; + goto cpu_store_unlock; + } + + origin_cpu = channel->target_cpu; + if (target_cpu == origin_cpu) + goto cpu_store_unlock; + + if (vmbus_send_modifychannel(channel->offermsg.child_relid, + hv_cpu_number_to_vp_number(target_cpu))) { + ret = -EIO; + goto cpu_store_unlock; + } + + /* + * Warning. At this point, there is *no* guarantee that the host will + * have successfully processed the vmbus_send_modifychannel() request. + * See the header comment of vmbus_send_modifychannel() for more info. + * + * Lags in the processing of the above vmbus_send_modifychannel() can + * result in missed interrupts if the "old" target CPU is taken offline + * before Hyper-V starts sending interrupts to the "new" target CPU. + * But apart from this offlining scenario, the code tolerates such + * lags. It will function correctly even if a channel interrupt comes + * in on a CPU that is different from the channel target_cpu value. + */ + + channel->target_cpu = target_cpu; + channel->target_vp = hv_cpu_number_to_vp_number(target_cpu); + channel->numa_node = cpu_to_node(target_cpu); + + /* See init_vp_index(). */ + if (hv_is_perf_channel(channel)) + hv_update_alloced_cpus(origin_cpu, target_cpu); + + /* Currently set only for storvsc channels. */ + if (channel->change_target_cpu_callback) { + (*channel->change_target_cpu_callback)(channel, + origin_cpu, target_cpu); + } + +cpu_store_unlock: + mutex_unlock(&vmbus_connection.channel_mutex); + cpus_read_unlock(); + return ret; +} +static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store); static ssize_t channel_pending_show(struct vmbus_channel *channel, char *buf) @@ -1830,7 +1998,7 @@ int vmbus_device_register(struct hv_device *child_device_obj) int ret; dev_set_name(&child_device_obj->device, "%pUl", - child_device_obj->channel->offermsg.offer.if_instance.b); + &child_device_obj->channel->offermsg.offer.if_instance); child_device_obj->device.bus = &hv_bus; child_device_obj->device.parent = &hv_acpi_dev->dev; @@ -2221,9 +2389,12 @@ static int vmbus_bus_suspend(struct device *dev) 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). + * Remove the channel from the array of channels and invalidate + * the channel's relid. Upon resume, vmbus_onoffer() will fix + * up the relid (and other fields, if necessary) and add the + * channel back to the array. */ + vmbus_channel_unmap_relid(channel); channel->offermsg.child_relid = INVALID_RELID; if (is_hvsock_channel(channel)) { @@ -2470,6 +2641,7 @@ static void __exit vmbus_exit(void) hv_debug_rm_all_dir(); vmbus_free_channels(); + kfree(vmbus_connection.channels); if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { kmsg_dump_unregister(&hv_kmsg_dumper); |