// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (c) 2009, Microsoft Corporation.
*
* Authors:
* Haiyang Zhang <[email protected]>
* Hank Janssen <[email protected]>
*/
#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 <linux/io.h>
#include <linux/set_memory.h>
#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"
struct vmbus_connection vmbus_connection = {
.conn_state = DISCONNECTED,
.unload_event = COMPLETION_INITIALIZER(
vmbus_connection.unload_event),
.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.
* VERSION_WIN7 and VERSION_WS2008 are no longer supported in
* Linux guests and are not listed.
*/
static __u32 vmbus_versions[] = {
VERSION_WIN10_V5_3,
VERSION_WIN10_V5_2,
VERSION_WIN10_V5_1,
VERSION_WIN10_V5,
VERSION_WIN10_V4_1,
VERSION_WIN10,
VERSION_WIN8_1,
VERSION_WIN8
};
/*
* 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_3;
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;
msg->msg_vtl = ms_hyperv.vtl;
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;
}
/*
* shared_gpa_boundary is zero in non-SNP VMs, so it's safe to always
* bitwise OR it
*/
msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]) |
ms_hyperv.shared_gpa_boundary;
msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]) |
ms_hyperv.shared_gpa_boundary;
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.rescind_work_queue =
create_workqueue("hv_vmbus_rescind");
if (!vmbus_connection.rescind_work_queue) {
ret = -ENOMEM;
goto cleanup;
}
vmbus_connection.ignore_any_offer_msg = false;
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 = 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] = hv_alloc_hyperv_page();
vmbus_connection.monitor_pages[1] = hv_alloc_hyperv_page();
if ((vmbus_connection.monitor_pages[0] == NULL) ||
(vmbus_connection.monitor_pages[1] == NULL)) {
ret = -ENOMEM;
goto cleanup;
}
ret = set_memory_decrypted((unsigned long)
vmbus_connection.monitor_pages[0], 1);
ret |= set_memory_decrypted((unsigned long)
vmbus_connection.monitor_pages[1], 1);
if (ret) {
/*
* If set_memory_decrypted() fails, the encryption state
* of the memory is unknown. So leak the memory instead
* of risking returning decrypted memory to the free list.
* For simplicity, always handle both pages the same.
*/
vmbus_connection.monitor_pages[0] = NULL;
vmbus_connection.monitor_pages[1] = NULL;
goto cleanup;
}
/*
* Set_memory_decrypted() will change the memory contents if
* decryption occurs, so zero monitor pages here.
*/
memset(vmbus_connection.monitor_pages[0], 0x00, HV_HYP_PAGE_SIZE);
memset(vmbus_connection.monitor_pages[1], 0x00, HV_HYP_PAGE_SIZE);
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;
}
if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
ret = -EINVAL;
goto cleanup;
}
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.rescind_work_queue)
destroy_workqueue(vmbus_connection.rescind_work_queue);
if (vmbus_connection.work_queue)
destroy_workqueue(vmbus_connection.work_queue);
if (vmbus_connection.int_page) {
hv_free_hyperv_page(vmbus_connection.int_page);
vmbus_connection.int_page = NULL;
}
if (vmbus_connection.monitor_pages[0]) {
if (!set_memory_encrypted(
(unsigned long)vmbus_connection.monitor_pages[0], 1))
hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
vmbus_connection.monitor_pages[0] = NULL;
}
if (vmbus_connection.monitor_pages[1]) {
if (!set_memory_encrypted(
(unsigned long)vmbus_connection.monitor_pages[1], 1))
hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
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;
void (*callback_fn)(void *context);
trace_vmbus_on_event(channel);
hv_debug_delay_test(channel, INTERRUPT_DELAY);
/* 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))
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);
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;
if (ms_hyperv.paravisor_present) {
if (hv_isolation_type_snp())
hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
NULL, sizeof(channel->sig_event));
else if (hv_isolation_type_tdx())
hv_tdx_hypercall(HVCALL_SIGNAL_EVENT | HV_HYPERCALL_FAST_BIT,
channel->sig_event, 0);
else
WARN_ON_ONCE(1);
} else {
hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
}
}
EXPORT_SYMBOL_GPL(vmbus_set_event);
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