--- /dev/null
+/*
+ *
+ * Copyright (c) 2009, Microsoft Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * 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/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/hyperv.h>
+#include <linux/export.h>
+#include <asm/hyperv.h>
+#include "hyperv_vmbus.h"
+
+
+struct vmbus_connection vmbus_connection = {
+ .conn_state = DISCONNECTED,
+ .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
+};
+
+/*
+ * Negotiated protocol version with the host.
+ */
+__u32 vmbus_proto_version;
+EXPORT_SYMBOL_GPL(vmbus_proto_version);
+
+static __u32 vmbus_get_next_version(__u32 current_version)
+{
+ switch (current_version) {
+ case (VERSION_WIN7):
+ return VERSION_WS2008;
+
+ case (VERSION_WIN8):
+ return VERSION_WIN7;
+
+ case (VERSION_WIN8_1):
+ return VERSION_WIN8;
+
+ case (VERSION_WS2008):
+ default:
+ return VERSION_INVAL;
+ }
+}
+
+static 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;
+
+ msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
+ msg->vmbus_version_requested = version;
+ msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
+ msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
+ msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
+ if (version == VERSION_WIN8_1) {
+ msg->target_vcpu = hv_context.vp_index[get_cpu()];
+ put_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));
+ 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;
+ } else {
+ return -ECONNREFUSED;
+ }
+
+ return ret;
+}
+
+/*
+ * vmbus_connect - Sends a connect request on the partition service connection
+ */
+int vmbus_connect(void)
+{
+ int ret = 0;
+ struct vmbus_channel_msginfo *msginfo = NULL;
+ __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;
+ }
+
+ INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
+ spin_lock_init(&vmbus_connection.channelmsg_lock);
+
+ INIT_LIST_HEAD(&vmbus_connection.chn_list);
+ spin_lock_init(&vmbus_connection.channel_lock);
+
+ /*
+ * Setup the vmbus event connection for channel interrupt
+ * abstraction stuff
+ */
+ vmbus_connection.int_page =
+ (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
+ 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 +
+ (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 *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
+ vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
+ 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.
+ */
+
+ version = VERSION_CURRENT;
+
+ do {
+ ret = vmbus_negotiate_version(msginfo, version);
+ if (ret == -ETIMEDOUT)
+ goto cleanup;
+
+ if (vmbus_connection.conn_state == CONNECTED)
+ break;
+
+ version = vmbus_get_next_version(version);
+ } while (version != VERSION_INVAL);
+
+ if (version == VERSION_INVAL)
+ goto cleanup;
+
+ vmbus_proto_version = version;
+ pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
+ host_info_eax, host_info_ebx >> 16,
+ host_info_ebx & 0xFFFF, host_info_ecx,
+ host_info_edx >> 24, host_info_edx & 0xFFFFFF,
+ version >> 16, version & 0xFFFF);
+
+ 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)
+{
+ if (vmbus_connection.work_queue) {
+ drain_workqueue(vmbus_connection.work_queue);
+ destroy_workqueue(vmbus_connection.work_queue);
+ }
+
+ if (vmbus_connection.int_page) {
+ free_pages((unsigned long)vmbus_connection.int_page, 0);
+ vmbus_connection.int_page = NULL;
+ }
+
+ free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
+ free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
+ vmbus_connection.monitor_pages[0] = NULL;
+ vmbus_connection.monitor_pages[1] = NULL;
+}
+
+/*
+ * Map the given relid to the corresponding channel based on the
+ * per-cpu list of channels that have been affinitized to this CPU.
+ * This will be used in the channel callback path as we can do this
+ * mapping in a lock-free fashion.
+ */
+static struct vmbus_channel *pcpu_relid2channel(u32 relid)
+{
+ struct vmbus_channel *channel;
+ struct vmbus_channel *found_channel = NULL;
+ int cpu = smp_processor_id();
+ struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
+
+ list_for_each_entry(channel, pcpu_head, percpu_list) {
+ if (channel->offermsg.child_relid == relid) {
+ found_channel = channel;
+ break;
+ }
+ }
+
+ return found_channel;
+}
+
+/*
+ * relid2channel - Get the channel object given its
+ * child relative id (ie channel id)
+ */
+struct vmbus_channel *relid2channel(u32 relid)
+{
+ struct vmbus_channel *channel;
+ struct vmbus_channel *found_channel = NULL;
+ unsigned long flags;
+ struct list_head *cur, *tmp;
+ struct vmbus_channel *cur_sc;
+
+ spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
+ list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
+ if (channel->offermsg.child_relid == relid) {
+ found_channel = channel;
+ break;
+ } else if (!list_empty(&channel->sc_list)) {
+ /*
+ * Deal with sub-channels.
+ */
+ list_for_each_safe(cur, tmp, &channel->sc_list) {
+ cur_sc = list_entry(cur, struct vmbus_channel,
+ sc_list);
+ if (cur_sc->offermsg.child_relid == relid) {
+ found_channel = cur_sc;
+ break;
+ }
+ }
+ }
+ }
+ spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
+
+ return found_channel;
+}
+
+/*
+ * process_chn_event - Process a channel event notification
+ */
+static void process_chn_event(u32 relid)
+{
+ struct vmbus_channel *channel;
+ void *arg;
+ bool read_state;
+ u32 bytes_to_read;
+
+ /*
+ * Find the channel based on this relid and invokes the
+ * channel callback to process the event
+ */
+ channel = pcpu_relid2channel(relid);
+
+ if (!channel)
+ return;
+
+ /*
+ * A channel once created is persistent even when there
+ * is no driver handling the device. An unloading driver
+ * sets the onchannel_callback to NULL on the same CPU
+ * as where this interrupt is handled (in an interrupt context).
+ * Thus, checking and invoking the driver specific callback takes
+ * care of orderly unloading of the driver.
+ */
+
+ if (channel->onchannel_callback != NULL) {
+ arg = channel->channel_callback_context;
+ read_state = channel->batched_reading;
+ /*
+ * This callback reads the messages sent by the host.
+ * We can 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.
+ */
+
+ do {
+ if (read_state)
+ hv_begin_read(&channel->inbound);
+ channel->onchannel_callback(arg);
+ if (read_state)
+ bytes_to_read = hv_end_read(&channel->inbound);
+ else
+ bytes_to_read = 0;
+ } while (read_state && (bytes_to_read != 0));
+ }
+}
+
+/*
+ * vmbus_on_event - Handler for events
+ */
+void vmbus_on_event(unsigned long data)
+{
+ u32 dword;
+ u32 maxdword;
+ int bit;
+ u32 relid;
+ u32 *recv_int_page = NULL;
+ void *page_addr;
+ int cpu = smp_processor_id();
+ union hv_synic_event_flags *event;
+
+ if ((vmbus_proto_version == VERSION_WS2008) ||
+ (vmbus_proto_version == VERSION_WIN7)) {
+ maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
+ recv_int_page = vmbus_connection.recv_int_page;
+ } else {
+ /*
+ * When the host is win8 and beyond, the event page
+ * can be directly checked to get the id of the channel
+ * that has the interrupt pending.
+ */
+ maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
+ page_addr = hv_context.synic_event_page[cpu];
+ event = (union hv_synic_event_flags *)page_addr +
+ VMBUS_MESSAGE_SINT;
+ recv_int_page = event->flags32;
+ }
+
+
+
+ /* Check events */
+ if (!recv_int_page)
+ return;
+ for (dword = 0; dword < maxdword; dword++) {
+ if (!recv_int_page[dword])
+ continue;
+ for (bit = 0; bit < 32; bit++) {
+ if (sync_test_and_clear_bit(bit,
+ (unsigned long *)&recv_int_page[dword])) {
+ relid = (dword << 5) + bit;
+
+ if (relid == 0)
+ /*
+ * Special case - vmbus
+ * channel protocol msg
+ */
+ continue;
+
+ process_chn_event(relid);
+ }
+ }
+ }
+}
+
+/*
+ * vmbus_post_msg - Send a msg on the vmbus's message connection
+ */
+int vmbus_post_msg(void *buffer, size_t buflen)
+{
+ union hv_connection_id conn_id;
+ int ret = 0;
+ int retries = 0;
+ u32 msec = 1;
+
+ conn_id.asu32 = 0;
+ conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
+
+ /*
+ * hv_post_message() can have transient failures because of
+ * insufficient resources. Retry the operation a couple of
+ * times before giving up.
+ */
+ while (retries < 20) {
+ ret = hv_post_message(conn_id, 1, buffer, buflen);
+
+ switch (ret) {
+ case HV_STATUS_INVALID_CONNECTION_ID:
+ /*
+ * We could get this if we send messages too
+ * frequently.
+ */
+ ret = -EAGAIN;
+ break;
+ case HV_STATUS_INSUFFICIENT_MEMORY:
+ case HV_STATUS_INSUFFICIENT_BUFFERS:
+ ret = -ENOMEM;
+ break;
+ case HV_STATUS_SUCCESS:
+ return ret;
+ default:
+ pr_err("hv_post_msg() failed; error code:%d\n", ret);
+ return -EINVAL;
+ }
+
+ retries++;
+ msleep(msec);
+ if (msec < 2048)
+ msec *= 2;
+ }
+ return ret;
+}
+
+/*
+ * vmbus_set_event - Send an event notification to the parent
+ */
+int vmbus_set_event(struct vmbus_channel *channel)
+{
+ u32 child_relid = channel->offermsg.child_relid;
+
+ if (!channel->is_dedicated_interrupt) {
+ /* Each u32 represents 32 channels */
+ sync_set_bit(child_relid & 31,
+ (unsigned long *)vmbus_connection.send_int_page +
+ (child_relid >> 5));
+ }
+
+ return hv_signal_event(channel->sig_event);
+}
Code Review / kvmfornfv.git / blobdiff