1eb65c8687
relid2channel() assumes vmbus channel array to be allocated when called.
However, in cases such as kdump/kexec, not all relids will be reset by the host.
When the second kernel boots and if the guest receives a vmbus interrupt during
vmbus driver initialization before vmbus_connect() is called, before it finishes,
or if it fails, the vmbus interrupt service routine is called which in turn calls
relid2channel() and can cause a null pointer dereference.
Print a warning and error out in relid2channel() for a channel id that's invalid
in the second kernel.
Fixes: 8b6a877c06 ("Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels")
Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/20230217204411.212709-1-mgamal@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
550 lines
15 KiB
C
550 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Copyright (c) 2009, Microsoft Corporation.
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*
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* Authors:
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* Haiyang Zhang <haiyangz@microsoft.com>
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* Hank Janssen <hjanssen@microsoft.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/wait.h>
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#include <linux/delay.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/hyperv.h>
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#include <linux/export.h>
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#include <linux/io.h>
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#include <linux/set_memory.h>
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#include <asm/mshyperv.h>
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#include "hyperv_vmbus.h"
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struct vmbus_connection vmbus_connection = {
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.conn_state = DISCONNECTED,
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.unload_event = COMPLETION_INITIALIZER(
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vmbus_connection.unload_event),
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.next_gpadl_handle = ATOMIC_INIT(0xE1E10),
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.ready_for_suspend_event = COMPLETION_INITIALIZER(
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vmbus_connection.ready_for_suspend_event),
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.ready_for_resume_event = COMPLETION_INITIALIZER(
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vmbus_connection.ready_for_resume_event),
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};
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EXPORT_SYMBOL_GPL(vmbus_connection);
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/*
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* Negotiated protocol version with the host.
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*/
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__u32 vmbus_proto_version;
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EXPORT_SYMBOL_GPL(vmbus_proto_version);
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/*
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* Table of VMBus versions listed from newest to oldest.
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* VERSION_WIN7 and VERSION_WS2008 are no longer supported in
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* Linux guests and are not listed.
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*/
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static __u32 vmbus_versions[] = {
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VERSION_WIN10_V5_3,
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VERSION_WIN10_V5_2,
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VERSION_WIN10_V5_1,
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VERSION_WIN10_V5,
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VERSION_WIN10_V4_1,
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VERSION_WIN10,
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VERSION_WIN8_1,
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VERSION_WIN8
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};
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/*
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* Maximal VMBus protocol version guests can negotiate. Useful to cap the
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* VMBus version for testing and debugging purpose.
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*/
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static uint max_version = VERSION_WIN10_V5_3;
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module_param(max_version, uint, S_IRUGO);
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MODULE_PARM_DESC(max_version,
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"Maximal VMBus protocol version which can be negotiated");
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int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
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{
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int ret = 0;
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struct vmbus_channel_initiate_contact *msg;
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unsigned long flags;
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init_completion(&msginfo->waitevent);
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msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
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memset(msg, 0, sizeof(*msg));
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msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
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msg->vmbus_version_requested = version;
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/*
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* VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
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* use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
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* and for subsequent messages, we must use the Message Connection ID
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* field in the host-returned Version Response Message. And, with
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* VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
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* tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
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* compatibility.
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*
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* On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
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*/
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if (version >= VERSION_WIN10_V5) {
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msg->msg_sint = VMBUS_MESSAGE_SINT;
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vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
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} else {
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msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
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vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
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}
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msg->monitor_page1 = vmbus_connection.monitor_pages_pa[0];
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msg->monitor_page2 = vmbus_connection.monitor_pages_pa[1];
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msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
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/*
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* Add to list before we send the request since we may
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* receive the response before returning from this routine
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*/
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
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list_add_tail(&msginfo->msglistentry,
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&vmbus_connection.chn_msg_list);
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
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ret = vmbus_post_msg(msg,
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sizeof(struct vmbus_channel_initiate_contact),
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true);
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trace_vmbus_negotiate_version(msg, ret);
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if (ret != 0) {
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
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list_del(&msginfo->msglistentry);
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
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flags);
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return ret;
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}
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/* Wait for the connection response */
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wait_for_completion(&msginfo->waitevent);
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spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
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list_del(&msginfo->msglistentry);
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spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
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/* Check if successful */
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if (msginfo->response.version_response.version_supported) {
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vmbus_connection.conn_state = CONNECTED;
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if (version >= VERSION_WIN10_V5)
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vmbus_connection.msg_conn_id =
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msginfo->response.version_response.msg_conn_id;
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} else {
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return -ECONNREFUSED;
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}
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return ret;
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}
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/*
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* vmbus_connect - Sends a connect request on the partition service connection
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*/
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int vmbus_connect(void)
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{
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struct vmbus_channel_msginfo *msginfo = NULL;
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int i, ret = 0;
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__u32 version;
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/* Initialize the vmbus connection */
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vmbus_connection.conn_state = CONNECTING;
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vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
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if (!vmbus_connection.work_queue) {
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ret = -ENOMEM;
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goto cleanup;
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}
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vmbus_connection.rescind_work_queue =
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create_workqueue("hv_vmbus_rescind");
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if (!vmbus_connection.rescind_work_queue) {
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ret = -ENOMEM;
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goto cleanup;
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}
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vmbus_connection.ignore_any_offer_msg = false;
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vmbus_connection.handle_primary_chan_wq =
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create_workqueue("hv_pri_chan");
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if (!vmbus_connection.handle_primary_chan_wq) {
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ret = -ENOMEM;
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goto cleanup;
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}
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vmbus_connection.handle_sub_chan_wq =
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create_workqueue("hv_sub_chan");
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if (!vmbus_connection.handle_sub_chan_wq) {
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ret = -ENOMEM;
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goto cleanup;
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}
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INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
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spin_lock_init(&vmbus_connection.channelmsg_lock);
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INIT_LIST_HEAD(&vmbus_connection.chn_list);
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mutex_init(&vmbus_connection.channel_mutex);
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/*
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* Setup the vmbus event connection for channel interrupt
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* abstraction stuff
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*/
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vmbus_connection.int_page =
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(void *)hv_alloc_hyperv_zeroed_page();
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if (vmbus_connection.int_page == NULL) {
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ret = -ENOMEM;
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goto cleanup;
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}
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vmbus_connection.recv_int_page = vmbus_connection.int_page;
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vmbus_connection.send_int_page =
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(void *)((unsigned long)vmbus_connection.int_page +
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(HV_HYP_PAGE_SIZE >> 1));
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/*
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* Setup the monitor notification facility. The 1st page for
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* parent->child and the 2nd page for child->parent
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*/
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vmbus_connection.monitor_pages[0] = (void *)hv_alloc_hyperv_zeroed_page();
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vmbus_connection.monitor_pages[1] = (void *)hv_alloc_hyperv_zeroed_page();
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if ((vmbus_connection.monitor_pages[0] == NULL) ||
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(vmbus_connection.monitor_pages[1] == NULL)) {
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ret = -ENOMEM;
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goto cleanup;
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}
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vmbus_connection.monitor_pages_original[0]
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= vmbus_connection.monitor_pages[0];
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vmbus_connection.monitor_pages_original[1]
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= vmbus_connection.monitor_pages[1];
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vmbus_connection.monitor_pages_pa[0]
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= virt_to_phys(vmbus_connection.monitor_pages[0]);
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vmbus_connection.monitor_pages_pa[1]
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= virt_to_phys(vmbus_connection.monitor_pages[1]);
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if (hv_is_isolation_supported()) {
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ret = set_memory_decrypted((unsigned long)
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vmbus_connection.monitor_pages[0],
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1);
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ret |= set_memory_decrypted((unsigned long)
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vmbus_connection.monitor_pages[1],
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1);
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if (ret)
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goto cleanup;
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/*
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* Isolation VM with AMD SNP needs to access monitor page via
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* address space above shared gpa boundary.
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*/
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if (hv_isolation_type_snp()) {
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vmbus_connection.monitor_pages_pa[0] +=
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ms_hyperv.shared_gpa_boundary;
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vmbus_connection.monitor_pages_pa[1] +=
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ms_hyperv.shared_gpa_boundary;
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vmbus_connection.monitor_pages[0]
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= memremap(vmbus_connection.monitor_pages_pa[0],
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HV_HYP_PAGE_SIZE,
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MEMREMAP_WB);
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if (!vmbus_connection.monitor_pages[0]) {
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ret = -ENOMEM;
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goto cleanup;
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}
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vmbus_connection.monitor_pages[1]
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= memremap(vmbus_connection.monitor_pages_pa[1],
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HV_HYP_PAGE_SIZE,
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MEMREMAP_WB);
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if (!vmbus_connection.monitor_pages[1]) {
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ret = -ENOMEM;
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goto cleanup;
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}
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}
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/*
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* Set memory host visibility hvcall smears memory
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* and so zero monitor pages here.
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*/
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memset(vmbus_connection.monitor_pages[0], 0x00,
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HV_HYP_PAGE_SIZE);
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memset(vmbus_connection.monitor_pages[1], 0x00,
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HV_HYP_PAGE_SIZE);
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}
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msginfo = kzalloc(sizeof(*msginfo) +
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sizeof(struct vmbus_channel_initiate_contact),
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GFP_KERNEL);
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if (msginfo == NULL) {
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ret = -ENOMEM;
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goto cleanup;
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}
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/*
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* Negotiate a compatible VMBUS version number with the
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* host. We start with the highest number we can support
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* and work our way down until we negotiate a compatible
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* version.
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*/
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for (i = 0; ; i++) {
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if (i == ARRAY_SIZE(vmbus_versions)) {
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ret = -EDOM;
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goto cleanup;
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}
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version = vmbus_versions[i];
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if (version > max_version)
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continue;
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ret = vmbus_negotiate_version(msginfo, version);
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if (ret == -ETIMEDOUT)
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goto cleanup;
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if (vmbus_connection.conn_state == CONNECTED)
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break;
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}
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if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
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pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
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version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
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ret = -EINVAL;
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goto cleanup;
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}
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vmbus_proto_version = version;
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pr_info("Vmbus version:%d.%d\n",
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version >> 16, version & 0xFFFF);
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vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
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sizeof(struct vmbus_channel *),
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GFP_KERNEL);
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if (vmbus_connection.channels == NULL) {
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ret = -ENOMEM;
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goto cleanup;
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}
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kfree(msginfo);
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return 0;
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cleanup:
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pr_err("Unable to connect to host\n");
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vmbus_connection.conn_state = DISCONNECTED;
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vmbus_disconnect();
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kfree(msginfo);
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return ret;
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}
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void vmbus_disconnect(void)
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{
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/*
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* First send the unload request to the host.
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*/
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vmbus_initiate_unload(false);
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if (vmbus_connection.handle_sub_chan_wq)
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destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
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if (vmbus_connection.handle_primary_chan_wq)
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destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
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if (vmbus_connection.rescind_work_queue)
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destroy_workqueue(vmbus_connection.rescind_work_queue);
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if (vmbus_connection.work_queue)
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destroy_workqueue(vmbus_connection.work_queue);
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if (vmbus_connection.int_page) {
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hv_free_hyperv_page((unsigned long)vmbus_connection.int_page);
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vmbus_connection.int_page = NULL;
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}
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if (hv_is_isolation_supported()) {
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/*
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* memunmap() checks input address is ioremap address or not
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* inside. It doesn't unmap any thing in the non-SNP CVM and
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* so not check CVM type here.
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*/
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memunmap(vmbus_connection.monitor_pages[0]);
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memunmap(vmbus_connection.monitor_pages[1]);
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set_memory_encrypted((unsigned long)
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vmbus_connection.monitor_pages_original[0],
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1);
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set_memory_encrypted((unsigned long)
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vmbus_connection.monitor_pages_original[1],
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1);
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}
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hv_free_hyperv_page((unsigned long)
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vmbus_connection.monitor_pages_original[0]);
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hv_free_hyperv_page((unsigned long)
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vmbus_connection.monitor_pages_original[1]);
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vmbus_connection.monitor_pages_original[0] =
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vmbus_connection.monitor_pages[0] = NULL;
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vmbus_connection.monitor_pages_original[1] =
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vmbus_connection.monitor_pages[1] = NULL;
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}
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/*
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* relid2channel - Get the channel object given its
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* child relative id (ie channel id)
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*/
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struct vmbus_channel *relid2channel(u32 relid)
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{
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if (vmbus_connection.channels == NULL) {
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pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
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return NULL;
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}
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if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
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return NULL;
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return READ_ONCE(vmbus_connection.channels[relid]);
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}
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/*
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* vmbus_on_event - Process a channel event notification
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*
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* For batched channels (default) optimize host to guest signaling
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* by ensuring:
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* 1. While reading the channel, we disable interrupts from host.
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* 2. Ensure that we process all posted messages from the host
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* before returning from this callback.
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* 3. Once we return, enable signaling from the host. Once this
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* state is set we check to see if additional packets are
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* available to read. In this case we repeat the process.
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* If this tasklet has been running for a long time
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* then reschedule ourselves.
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*/
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void vmbus_on_event(unsigned long data)
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{
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struct vmbus_channel *channel = (void *) data;
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void (*callback_fn)(void *context);
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trace_vmbus_on_event(channel);
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hv_debug_delay_test(channel, INTERRUPT_DELAY);
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/* A channel once created is persistent even when
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* there is no driver handling the device. An
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* unloading driver sets the onchannel_callback to NULL.
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*/
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callback_fn = READ_ONCE(channel->onchannel_callback);
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if (unlikely(!callback_fn))
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return;
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(*callback_fn)(channel->channel_callback_context);
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if (channel->callback_mode != HV_CALL_BATCHED)
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return;
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if (likely(hv_end_read(&channel->inbound) == 0))
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return;
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hv_begin_read(&channel->inbound);
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tasklet_schedule(&channel->callback_event);
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}
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/*
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* vmbus_post_msg - Send a msg on the vmbus's message connection
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*/
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int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
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{
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struct vmbus_channel_message_header *hdr;
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union hv_connection_id conn_id;
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int ret = 0;
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int retries = 0;
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u32 usec = 1;
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conn_id.asu32 = 0;
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conn_id.u.id = vmbus_connection.msg_conn_id;
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/*
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* hv_post_message() can have transient failures because of
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* insufficient resources. Retry the operation a couple of
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* times before giving up.
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*/
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while (retries < 100) {
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ret = hv_post_message(conn_id, 1, buffer, buflen);
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switch (ret) {
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case HV_STATUS_INVALID_CONNECTION_ID:
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/*
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|
* 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 (hv_isolation_type_snp())
|
|
hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
|
|
NULL, sizeof(channel->sig_event));
|
|
else
|
|
hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vmbus_set_event);
|