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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/hv/channel_mgmt.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/hv/channel_mgmt.c')
-rw-r--r--drivers/hv/channel_mgmt.c1619
1 files changed, 1619 insertions, 0 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
new file mode 100644
index 000000000..d95e567a1
--- /dev/null
+++ b/drivers/hv/channel_mgmt.c
@@ -0,0 +1,1619 @@
+// 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 <linux/sched/isolation.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,
+ .allowed_in_isolated = false,
+ },
+
+ /* SCSI */
+ { .dev_type = HV_SCSI,
+ HV_SCSI_GUID,
+ .perf_device = true,
+ .allowed_in_isolated = true,
+ },
+
+ /* Fibre Channel */
+ { .dev_type = HV_FC,
+ HV_SYNTHFC_GUID,
+ .perf_device = true,
+ .allowed_in_isolated = false,
+ },
+
+ /* Synthetic NIC */
+ { .dev_type = HV_NIC,
+ HV_NIC_GUID,
+ .perf_device = true,
+ .allowed_in_isolated = true,
+ },
+
+ /* Network Direct */
+ { .dev_type = HV_ND,
+ HV_ND_GUID,
+ .perf_device = true,
+ .allowed_in_isolated = false,
+ },
+
+ /* PCIE */
+ { .dev_type = HV_PCIE,
+ HV_PCIE_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* Synthetic Frame Buffer */
+ { .dev_type = HV_FB,
+ HV_SYNTHVID_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* Synthetic Keyboard */
+ { .dev_type = HV_KBD,
+ HV_KBD_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* Synthetic MOUSE */
+ { .dev_type = HV_MOUSE,
+ HV_MOUSE_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* KVP */
+ { .dev_type = HV_KVP,
+ HV_KVP_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* Time Synch */
+ { .dev_type = HV_TS,
+ HV_TS_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = true,
+ },
+
+ /* Heartbeat */
+ { .dev_type = HV_HB,
+ HV_HEART_BEAT_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = true,
+ },
+
+ /* Shutdown */
+ { .dev_type = HV_SHUTDOWN,
+ HV_SHUTDOWN_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = true,
+ },
+
+ /* File copy */
+ { .dev_type = HV_FCOPY,
+ HV_FCOPY_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* Backup */
+ { .dev_type = HV_BACKUP,
+ HV_VSS_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* Dynamic Memory */
+ { .dev_type = HV_DM,
+ HV_DM_GUID,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+
+ /* Unknown GUID */
+ { .dev_type = HV_UNKNOWN,
+ .perf_device = false,
+ .allowed_in_isolated = false,
+ },
+};
+
+static const struct {
+ guid_t guid;
+} vmbus_unsupported_devs[] = {
+ { HV_AVMA1_GUID },
+ { HV_AVMA2_GUID },
+ { HV_RDV_GUID },
+ { HV_IMC_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
+ * @buflen: Length of the 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,
+ u32 buflen, 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;
+
+ /* Check that there's enough space for icframe_vercnt, icmsg_vercnt */
+ if (buflen < ICMSG_HDR + offsetof(struct icmsg_negotiate, reserved)) {
+ pr_err_ratelimited("Invalid icmsg negotiate\n");
+ return false;
+ }
+
+ icmsghdrp->icmsgsize = 0x10;
+ negop = (struct icmsg_negotiate *)&buf[ICMSG_HDR];
+
+ icframe_major = negop->icframe_vercnt;
+ icframe_minor = 0;
+
+ icmsg_major = negop->icmsg_vercnt;
+ icmsg_minor = 0;
+
+ /* Validate negop packet */
+ if (icframe_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
+ icmsg_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
+ ICMSG_NEGOTIATE_PKT_SIZE(icframe_major, icmsg_major) > buflen) {
+ pr_err_ratelimited("Invalid icmsg negotiate - icframe_major: %u, icmsg_major: %u\n",
+ icframe_major, icmsg_major);
+ goto fw_error;
+ }
+
+ /*
+ * 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 application 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_allocated_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);
+
+ 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;
+ newchannel->primary_channel = channel;
+ break;
+ }
+ }
+
+ 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);
+
+ 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.
+ */
+ 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);
+}
+
+/*
+ * Check if CPUs used by other channels of the same device.
+ * It should only be called by init_vp_index().
+ */
+static bool hv_cpuself_used(u32 cpu, struct vmbus_channel *chn)
+{
+ struct vmbus_channel *primary = chn->primary_channel;
+ struct vmbus_channel *sc;
+
+ lockdep_assert_held(&vmbus_connection.channel_mutex);
+
+ if (!primary)
+ return false;
+
+ if (primary->target_cpu == cpu)
+ return true;
+
+ list_for_each_entry(sc, &primary->sc_list, sc_list)
+ if (sc != chn && sc->target_cpu == cpu)
+ return true;
+
+ return false;
+}
+
+/*
+ * We use this state to statically distribute the channel interrupt load.
+ */
+static int next_numa_node_id;
+
+/*
+ * We can statically distribute the incoming channel interrupt load
+ * by binding a channel to VCPU.
+ *
+ * For non-performance critical channels we assign the VMBUS_CONNECT_CPU.
+ * 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);
+ u32 i, ncpu = num_online_cpus();
+ cpumask_var_t available_mask;
+ struct cpumask *allocated_mask;
+ const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
+ u32 target_cpu;
+ int numa_node;
+
+ if (!perf_chn ||
+ !alloc_cpumask_var(&available_mask, GFP_KERNEL) ||
+ cpumask_empty(hk_mask)) {
+ /*
+ * 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.
+ * If all the cpus are isolated, bind it to
+ * VMBUS_CONNECT_CPU.
+ */
+ channel->target_cpu = VMBUS_CONNECT_CPU;
+ if (perf_chn)
+ hv_set_allocated_cpu(VMBUS_CONNECT_CPU);
+ return;
+ }
+
+ for (i = 1; i <= ncpu + 1; i++) {
+ 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;
+ }
+ allocated_mask = &hv_context.hv_numa_map[numa_node];
+
+retry:
+ cpumask_xor(available_mask, allocated_mask, cpumask_of_node(numa_node));
+ cpumask_and(available_mask, available_mask, hk_mask);
+
+ if (cpumask_empty(available_mask)) {
+ /*
+ * We have cycled through all the CPUs in the node;
+ * reset the allocated map.
+ */
+ cpumask_clear(allocated_mask);
+ goto retry;
+ }
+
+ target_cpu = cpumask_first(available_mask);
+ cpumask_set_cpu(target_cpu, allocated_mask);
+
+ if (channel->offermsg.offer.sub_channel_index >= ncpu ||
+ i > ncpu || !hv_cpuself_used(target_cpu, channel))
+ break;
+ }
+
+ 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.
+ *
+ * NB. A malicious or compromised Hyper-V could send a spurious
+ * message of type CHANNELMSG_UNLOAD_RESPONSE, and trigger a call
+ * of the complete() below. Make sure that unload_event has been
+ * initialized by the time this complete() is executed.
+ */
+ 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;
+
+ reinit_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;
+
+ 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;
+}
+
+static bool vmbus_is_valid_offer(const struct vmbus_channel_offer_channel *offer)
+{
+ const guid_t *guid = &offer->offer.if_type;
+ u16 i;
+
+ if (!hv_is_isolation_supported())
+ return true;
+
+ if (is_hvsock_offer(offer))
+ return true;
+
+ for (i = 0; i < ARRAY_SIZE(vmbus_devs); i++) {
+ if (guid_equal(guid, &vmbus_devs[i].guid))
+ return vmbus_devs[i].allowed_in_isolated;
+ }
+ return false;
+}
+
+/*
+ * 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);
+
+ if (!vmbus_is_valid_offer(offer)) {
+ pr_err_ratelimited("Invalid offer %d from the host supporting isolation\n",
+ offer->child_relid);
+ atomic_dec(&vmbus_connection.offer_in_progress);
+ return;
+ }
+
+ 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);
+ if (channel != NULL) {
+ /*
+ * Guarantee that no other instance of vmbus_onoffer_rescind()
+ * has got a reference to the channel object. Synchronize on
+ * &vmbus_connection.channel_mutex.
+ */
+ if (channel->rescind_ref) {
+ mutex_unlock(&vmbus_connection.channel_mutex);
+ return;
+ }
+ channel->rescind_ref = true;
+ }
+ 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_onmodifychannel_response - Modify Channel response handler.
+ *
+ * This is invoked when we received a response to our channel modify request.
+ * Find the matching request, copy the response and signal the requesting thread.
+ */
+static void vmbus_onmodifychannel_response(struct vmbus_channel_message_header *hdr)
+{
+ struct vmbus_channel_modifychannel_response *response;
+ struct vmbus_channel_msginfo *msginfo;
+ unsigned long flags;
+
+ response = (struct vmbus_channel_modifychannel_response *)hdr;
+
+ trace_vmbus_onmodifychannel_response(response);
+
+ /*
+ * Find the modify msg, copy the response 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) {
+ struct vmbus_channel_message_header *responseheader =
+ (struct vmbus_channel_message_header *)msginfo->msg;
+
+ if (responseheader->msgtype == CHANNELMSG_MODIFYCHANNEL) {
+ struct vmbus_channel_modifychannel *modifymsg;
+
+ modifymsg = (struct vmbus_channel_modifychannel *)msginfo->msg;
+ if (modifymsg->child_relid == response->child_relid) {
+ memcpy(&msginfo->response.modify_response, response,
+ sizeof(*response));
+ 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},
+ { CHANNELMSG_MODIFYCHANNEL_RESPONSE, 1, vmbus_onmodifychannel_response,
+ sizeof(struct vmbus_channel_modifychannel_response)},
+};
+
+/*
+ * 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 = kzalloc(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;
+}
+
+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);
+
+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);