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-rw-r--r--drivers/hv/connection.c446
1 files changed, 446 insertions, 0 deletions
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
new file mode 100644
index 000000000..683fdfa3e
--- /dev/null
+++ b/drivers/hv/connection.c
@@ -0,0 +1,446 @@
+// 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/sched.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/hyperv.h>
+#include <linux/export.h>
+#include <asm/mshyperv.h>
+
+#include "hyperv_vmbus.h"
+
+
+struct vmbus_connection vmbus_connection = {
+ .conn_state = DISCONNECTED,
+ .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
+
+ .ready_for_suspend_event= COMPLETION_INITIALIZER(
+ vmbus_connection.ready_for_suspend_event),
+ .ready_for_resume_event = COMPLETION_INITIALIZER(
+ vmbus_connection.ready_for_resume_event),
+};
+EXPORT_SYMBOL_GPL(vmbus_connection);
+
+/*
+ * Negotiated protocol version with the host.
+ */
+__u32 vmbus_proto_version;
+EXPORT_SYMBOL_GPL(vmbus_proto_version);
+
+/*
+ * Table of VMBus versions listed from newest to oldest.
+ */
+static __u32 vmbus_versions[] = {
+ VERSION_WIN10_V5_2,
+ VERSION_WIN10_V5_1,
+ VERSION_WIN10_V5,
+ VERSION_WIN10_V4_1,
+ VERSION_WIN10,
+ VERSION_WIN8_1,
+ VERSION_WIN8,
+ VERSION_WIN7,
+ VERSION_WS2008
+};
+
+/*
+ * Maximal VMBus protocol version guests can negotiate. Useful to cap the
+ * VMBus version for testing and debugging purpose.
+ */
+static uint max_version = VERSION_WIN10_V5_2;
+
+module_param(max_version, uint, S_IRUGO);
+MODULE_PARM_DESC(max_version,
+ "Maximal VMBus protocol version which can be negotiated");
+
+int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
+{
+ int ret = 0;
+ struct vmbus_channel_initiate_contact *msg;
+ unsigned long flags;
+
+ init_completion(&msginfo->waitevent);
+
+ msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
+
+ memset(msg, 0, sizeof(*msg));
+ msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
+ msg->vmbus_version_requested = version;
+
+ /*
+ * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
+ * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
+ * and for subsequent messages, we must use the Message Connection ID
+ * field in the host-returned Version Response Message. And, with
+ * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
+ * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
+ * compatibility.
+ *
+ * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
+ */
+ if (version >= VERSION_WIN10_V5) {
+ msg->msg_sint = VMBUS_MESSAGE_SINT;
+ vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
+ } else {
+ msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
+ vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
+ }
+
+ msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
+ msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
+ msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
+
+ /*
+ * Add to list before we send the request since we may
+ * receive the response before returning from this routine
+ */
+ spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+ list_add_tail(&msginfo->msglistentry,
+ &vmbus_connection.chn_msg_list);
+
+ spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+ ret = vmbus_post_msg(msg,
+ sizeof(struct vmbus_channel_initiate_contact),
+ true);
+
+ trace_vmbus_negotiate_version(msg, ret);
+
+ if (ret != 0) {
+ spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+ list_del(&msginfo->msglistentry);
+ spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
+ flags);
+ return ret;
+ }
+
+ /* Wait for the connection response */
+ wait_for_completion(&msginfo->waitevent);
+
+ spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+ list_del(&msginfo->msglistentry);
+ spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+
+ /* Check if successful */
+ if (msginfo->response.version_response.version_supported) {
+ vmbus_connection.conn_state = CONNECTED;
+
+ if (version >= VERSION_WIN10_V5)
+ vmbus_connection.msg_conn_id =
+ msginfo->response.version_response.msg_conn_id;
+ } else {
+ return -ECONNREFUSED;
+ }
+
+ return ret;
+}
+
+/*
+ * vmbus_connect - Sends a connect request on the partition service connection
+ */
+int vmbus_connect(void)
+{
+ struct vmbus_channel_msginfo *msginfo = NULL;
+ int i, ret = 0;
+ __u32 version;
+
+ /* Initialize the vmbus connection */
+ vmbus_connection.conn_state = CONNECTING;
+ vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
+ if (!vmbus_connection.work_queue) {
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+
+ vmbus_connection.handle_primary_chan_wq =
+ create_workqueue("hv_pri_chan");
+ if (!vmbus_connection.handle_primary_chan_wq) {
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+
+ vmbus_connection.handle_sub_chan_wq =
+ create_workqueue("hv_sub_chan");
+ if (!vmbus_connection.handle_sub_chan_wq) {
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+
+ INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
+ spin_lock_init(&vmbus_connection.channelmsg_lock);
+
+ INIT_LIST_HEAD(&vmbus_connection.chn_list);
+ mutex_init(&vmbus_connection.channel_mutex);
+
+ /*
+ * Setup the vmbus event connection for channel interrupt
+ * abstraction stuff
+ */
+ vmbus_connection.int_page =
+ (void *)hv_alloc_hyperv_zeroed_page();
+ if (vmbus_connection.int_page == NULL) {
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+
+ vmbus_connection.recv_int_page = vmbus_connection.int_page;
+ vmbus_connection.send_int_page =
+ (void *)((unsigned long)vmbus_connection.int_page +
+ (HV_HYP_PAGE_SIZE >> 1));
+
+ /*
+ * Setup the monitor notification facility. The 1st page for
+ * parent->child and the 2nd page for child->parent
+ */
+ vmbus_connection.monitor_pages[0] = (void *)hv_alloc_hyperv_zeroed_page();
+ vmbus_connection.monitor_pages[1] = (void *)hv_alloc_hyperv_zeroed_page();
+ if ((vmbus_connection.monitor_pages[0] == NULL) ||
+ (vmbus_connection.monitor_pages[1] == NULL)) {
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+
+ msginfo = kzalloc(sizeof(*msginfo) +
+ sizeof(struct vmbus_channel_initiate_contact),
+ GFP_KERNEL);
+ if (msginfo == NULL) {
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+
+ /*
+ * Negotiate a compatible VMBUS version number with the
+ * host. We start with the highest number we can support
+ * and work our way down until we negotiate a compatible
+ * version.
+ */
+
+ for (i = 0; ; i++) {
+ if (i == ARRAY_SIZE(vmbus_versions)) {
+ ret = -EDOM;
+ goto cleanup;
+ }
+
+ version = vmbus_versions[i];
+ if (version > max_version)
+ continue;
+
+ ret = vmbus_negotiate_version(msginfo, version);
+ if (ret == -ETIMEDOUT)
+ goto cleanup;
+
+ if (vmbus_connection.conn_state == CONNECTED)
+ break;
+ }
+
+ vmbus_proto_version = version;
+ pr_info("Vmbus version:%d.%d\n",
+ version >> 16, version & 0xFFFF);
+
+ vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
+ sizeof(struct vmbus_channel *),
+ GFP_KERNEL);
+ if (vmbus_connection.channels == NULL) {
+ ret = -ENOMEM;
+ goto cleanup;
+ }
+
+ kfree(msginfo);
+ return 0;
+
+cleanup:
+ pr_err("Unable to connect to host\n");
+
+ vmbus_connection.conn_state = DISCONNECTED;
+ vmbus_disconnect();
+
+ kfree(msginfo);
+
+ return ret;
+}
+
+void vmbus_disconnect(void)
+{
+ /*
+ * First send the unload request to the host.
+ */
+ vmbus_initiate_unload(false);
+
+ if (vmbus_connection.handle_sub_chan_wq)
+ destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
+
+ if (vmbus_connection.handle_primary_chan_wq)
+ destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
+
+ if (vmbus_connection.work_queue)
+ destroy_workqueue(vmbus_connection.work_queue);
+
+ if (vmbus_connection.int_page) {
+ hv_free_hyperv_page((unsigned long)vmbus_connection.int_page);
+ vmbus_connection.int_page = NULL;
+ }
+
+ hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[0]);
+ hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[1]);
+ vmbus_connection.monitor_pages[0] = NULL;
+ vmbus_connection.monitor_pages[1] = NULL;
+}
+
+/*
+ * relid2channel - Get the channel object given its
+ * child relative id (ie channel id)
+ */
+struct vmbus_channel *relid2channel(u32 relid)
+{
+ if (vmbus_connection.channels == NULL) {
+ pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
+ return NULL;
+ }
+ if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
+ return NULL;
+ return READ_ONCE(vmbus_connection.channels[relid]);
+}
+
+/*
+ * vmbus_on_event - Process a channel event notification
+ *
+ * For batched channels (default) optimize host to guest signaling
+ * by ensuring:
+ * 1. While reading the channel, we disable interrupts from host.
+ * 2. Ensure that we process all posted messages from the host
+ * before returning from this callback.
+ * 3. Once we return, enable signaling from the host. Once this
+ * state is set we check to see if additional packets are
+ * available to read. In this case we repeat the process.
+ * If this tasklet has been running for a long time
+ * then reschedule ourselves.
+ */
+void vmbus_on_event(unsigned long data)
+{
+ struct vmbus_channel *channel = (void *) data;
+ unsigned long time_limit = jiffies + 2;
+
+ trace_vmbus_on_event(channel);
+
+ hv_debug_delay_test(channel, INTERRUPT_DELAY);
+ do {
+ void (*callback_fn)(void *);
+
+ /* A channel once created is persistent even when
+ * there is no driver handling the device. An
+ * unloading driver sets the onchannel_callback to NULL.
+ */
+ callback_fn = READ_ONCE(channel->onchannel_callback);
+ if (unlikely(callback_fn == NULL))
+ return;
+
+ (*callback_fn)(channel->channel_callback_context);
+
+ if (channel->callback_mode != HV_CALL_BATCHED)
+ return;
+
+ if (likely(hv_end_read(&channel->inbound) == 0))
+ return;
+
+ hv_begin_read(&channel->inbound);
+ } while (likely(time_before(jiffies, time_limit)));
+
+ /* The time limit (2 jiffies) has been reached */
+ tasklet_schedule(&channel->callback_event);
+}
+
+/*
+ * vmbus_post_msg - Send a msg on the vmbus's message connection
+ */
+int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
+{
+ struct vmbus_channel_message_header *hdr;
+ union hv_connection_id conn_id;
+ int ret = 0;
+ int retries = 0;
+ u32 usec = 1;
+
+ conn_id.asu32 = 0;
+ conn_id.u.id = vmbus_connection.msg_conn_id;
+
+ /*
+ * hv_post_message() can have transient failures because of
+ * insufficient resources. Retry the operation a couple of
+ * times before giving up.
+ */
+ while (retries < 100) {
+ ret = hv_post_message(conn_id, 1, buffer, buflen);
+
+ switch (ret) {
+ case HV_STATUS_INVALID_CONNECTION_ID:
+ /*
+ * See vmbus_negotiate_version(): VMBus protocol 5.0
+ * and higher require that we must use
+ * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
+ * Contact message, but on old hosts that only
+ * support VMBus protocol 4.0 or lower, here we get
+ * HV_STATUS_INVALID_CONNECTION_ID and we should
+ * return an error immediately without retrying.
+ */
+ hdr = buffer;
+ if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
+ return -EINVAL;
+ /*
+ * We could get this if we send messages too
+ * frequently.
+ */
+ ret = -EAGAIN;
+ break;
+ case HV_STATUS_INSUFFICIENT_MEMORY:
+ case HV_STATUS_INSUFFICIENT_BUFFERS:
+ ret = -ENOBUFS;
+ break;
+ case HV_STATUS_SUCCESS:
+ return ret;
+ default:
+ pr_err("hv_post_msg() failed; error code:%d\n", ret);
+ return -EINVAL;
+ }
+
+ retries++;
+ if (can_sleep && usec > 1000)
+ msleep(usec / 1000);
+ else if (usec < MAX_UDELAY_MS * 1000)
+ udelay(usec);
+ else
+ mdelay(usec / 1000);
+
+ if (retries < 22)
+ usec *= 2;
+ }
+ return ret;
+}
+
+/*
+ * vmbus_set_event - Send an event notification to the parent
+ */
+void vmbus_set_event(struct vmbus_channel *channel)
+{
+ u32 child_relid = channel->offermsg.child_relid;
+
+ if (!channel->is_dedicated_interrupt)
+ vmbus_send_interrupt(child_relid);
+
+ ++channel->sig_events;
+
+ hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
+}
+EXPORT_SYMBOL_GPL(vmbus_set_event);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 06:25:56 +0000