mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-15 08:56:48 +07:00
086a6f68d6
Switch to using the hvutil_device_state state machine from using kvp_transaction.active. State transitions are: -> HVUTIL_DEVICE_INIT when driver loads or on device release -> HVUTIL_READY if the handshake was successful -> HVUTIL_HOSTMSG_RECEIVED when there is a non-negotiation message from the host -> HVUTIL_USERSPACE_REQ after we sent the message to the userspace daemon -> HVUTIL_USERSPACE_RECV after/if the userspace daemon has replied -> HVUTIL_READY after we respond to the host -> HVUTIL_DEVICE_DYING on driver unload In hv_vss_onchannelcallback() process ICMSGTYPE_NEGOTIATE messages even when the userspace daemon is disconnected, otherwise we can make the host think we don't support VSS and disable the service completely. Unfortunately there is no good way we can figure out that the userspace daemon has died (unless we start treating all timeouts as such), add a protection against processing new VSS_OP_REGISTER messages while being in the middle of a transaction (HVUTIL_USERSPACE_REQ or HVUTIL_USERSPACE_RECV state). Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
339 lines
8.6 KiB
C
339 lines
8.6 KiB
C
/*
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* An implementation of host initiated guest snapshot.
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*
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*
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* Copyright (C) 2013, Microsoft, Inc.
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* Author : K. Y. Srinivasan <kys@microsoft.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/net.h>
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#include <linux/nls.h>
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#include <linux/connector.h>
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#include <linux/workqueue.h>
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#include <linux/hyperv.h>
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#include "hyperv_vmbus.h"
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#define VSS_MAJOR 5
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#define VSS_MINOR 0
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#define VSS_VERSION (VSS_MAJOR << 16 | VSS_MINOR)
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#define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))
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/*
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* Global state maintained for transaction that is being processed. For a class
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* of integration services, including the "VSS service", the specified protocol
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* is a "request/response" protocol which means that there can only be single
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* outstanding transaction from the host at any given point in time. We use
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* this to simplify memory management in this driver - we cache and process
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* only one message at a time.
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*
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* While the request/response protocol is guaranteed by the host, we further
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* ensure this by serializing packet processing in this driver - we do not
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* read additional packets from the VMBUs until the current packet is fully
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* handled.
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*/
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static struct {
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int state; /* hvutil_device_state */
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int recv_len; /* number of bytes received. */
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struct vmbus_channel *recv_channel; /* chn we got the request */
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u64 recv_req_id; /* request ID. */
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struct hv_vss_msg *msg; /* current message */
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void *vss_context; /* for the channel callback */
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} vss_transaction;
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static void vss_respond_to_host(int error);
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static struct cb_id vss_id = { CN_VSS_IDX, CN_VSS_VAL };
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static const char vss_name[] = "vss_kernel_module";
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static __u8 *recv_buffer;
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static void vss_send_op(struct work_struct *dummy);
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static void vss_timeout_func(struct work_struct *dummy);
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static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
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static DECLARE_WORK(vss_send_op_work, vss_send_op);
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/*
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* Callback when data is received from user mode.
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*/
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static void vss_timeout_func(struct work_struct *dummy)
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{
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/*
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* Timeout waiting for userspace component to reply happened.
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*/
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pr_warn("VSS: timeout waiting for daemon to reply\n");
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vss_respond_to_host(HV_E_FAIL);
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/* Transaction is finished, reset the state. */
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if (vss_transaction.state > HVUTIL_READY)
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vss_transaction.state = HVUTIL_READY;
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hv_poll_channel(vss_transaction.vss_context,
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hv_vss_onchannelcallback);
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}
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static void
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vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
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{
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struct hv_vss_msg *vss_msg;
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vss_msg = (struct hv_vss_msg *)msg->data;
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/*
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* Don't process registration messages if we're in the middle of
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* a transaction processing.
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*/
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if (vss_transaction.state > HVUTIL_READY &&
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vss_msg->vss_hdr.operation == VSS_OP_REGISTER)
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return;
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if (vss_transaction.state == HVUTIL_DEVICE_INIT &&
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vss_msg->vss_hdr.operation == VSS_OP_REGISTER) {
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pr_info("VSS daemon registered\n");
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vss_transaction.state = HVUTIL_READY;
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} else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
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vss_transaction.state = HVUTIL_USERSPACE_RECV;
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if (cancel_delayed_work_sync(&vss_timeout_work)) {
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vss_respond_to_host(vss_msg->error);
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/* Transaction is finished, reset the state. */
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vss_transaction.state = HVUTIL_READY;
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hv_poll_channel(vss_transaction.vss_context,
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hv_vss_onchannelcallback);
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}
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} else {
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/* This is a spurious call! */
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pr_warn("VSS: Transaction not active\n");
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return;
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}
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}
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static void vss_send_op(struct work_struct *dummy)
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{
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int op = vss_transaction.msg->vss_hdr.operation;
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int rc;
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struct cn_msg *msg;
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struct hv_vss_msg *vss_msg;
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/* The transaction state is wrong. */
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if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
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return;
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msg = kzalloc(sizeof(*msg) + sizeof(*vss_msg), GFP_ATOMIC);
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if (!msg)
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return;
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vss_msg = (struct hv_vss_msg *)msg->data;
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msg->id.idx = CN_VSS_IDX;
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msg->id.val = CN_VSS_VAL;
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vss_msg->vss_hdr.operation = op;
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msg->len = sizeof(struct hv_vss_msg);
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vss_transaction.state = HVUTIL_USERSPACE_REQ;
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rc = cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
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if (rc) {
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pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
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if (cancel_delayed_work_sync(&vss_timeout_work)) {
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vss_respond_to_host(HV_E_FAIL);
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vss_transaction.state = HVUTIL_READY;
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}
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}
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kfree(msg);
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return;
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}
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/*
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* Send a response back to the host.
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*/
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static void
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vss_respond_to_host(int error)
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{
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struct icmsg_hdr *icmsghdrp;
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u32 buf_len;
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struct vmbus_channel *channel;
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u64 req_id;
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/*
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* Copy the global state for completing the transaction. Note that
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* only one transaction can be active at a time.
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*/
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buf_len = vss_transaction.recv_len;
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channel = vss_transaction.recv_channel;
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req_id = vss_transaction.recv_req_id;
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icmsghdrp = (struct icmsg_hdr *)
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&recv_buffer[sizeof(struct vmbuspipe_hdr)];
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if (channel->onchannel_callback == NULL)
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/*
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* We have raced with util driver being unloaded;
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* silently return.
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*/
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return;
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icmsghdrp->status = error;
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icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
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vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
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VM_PKT_DATA_INBAND, 0);
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}
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/*
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* This callback is invoked when we get a VSS message from the host.
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* The host ensures that only one VSS transaction can be active at a time.
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*/
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void hv_vss_onchannelcallback(void *context)
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{
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struct vmbus_channel *channel = context;
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u32 recvlen;
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u64 requestid;
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struct hv_vss_msg *vss_msg;
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struct icmsg_hdr *icmsghdrp;
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struct icmsg_negotiate *negop = NULL;
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if (vss_transaction.state > HVUTIL_READY) {
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/*
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* We will defer processing this callback once
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* the current transaction is complete.
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*/
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vss_transaction.vss_context = context;
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return;
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}
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vss_transaction.vss_context = NULL;
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vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
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&requestid);
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if (recvlen > 0) {
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icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
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sizeof(struct vmbuspipe_hdr)];
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if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
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vmbus_prep_negotiate_resp(icmsghdrp, negop,
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recv_buffer, UTIL_FW_VERSION,
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VSS_VERSION);
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} else {
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vss_msg = (struct hv_vss_msg *)&recv_buffer[
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sizeof(struct vmbuspipe_hdr) +
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sizeof(struct icmsg_hdr)];
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/*
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* Stash away this global state for completing the
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* transaction; note transactions are serialized.
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*/
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vss_transaction.recv_len = recvlen;
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vss_transaction.recv_channel = channel;
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vss_transaction.recv_req_id = requestid;
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vss_transaction.msg = (struct hv_vss_msg *)vss_msg;
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switch (vss_msg->vss_hdr.operation) {
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/*
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* Initiate a "freeze/thaw"
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* operation in the guest.
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* We respond to the host once
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* the operation is complete.
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*
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* We send the message to the
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* user space daemon and the
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* operation is performed in
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* the daemon.
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*/
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case VSS_OP_FREEZE:
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case VSS_OP_THAW:
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if (vss_transaction.state < HVUTIL_READY) {
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/* Userspace is not registered yet */
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vss_respond_to_host(HV_E_FAIL);
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return;
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}
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vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
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schedule_work(&vss_send_op_work);
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schedule_delayed_work(&vss_timeout_work,
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VSS_USERSPACE_TIMEOUT);
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return;
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case VSS_OP_HOT_BACKUP:
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vss_msg->vss_cf.flags =
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VSS_HBU_NO_AUTO_RECOVERY;
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vss_respond_to_host(0);
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return;
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case VSS_OP_GET_DM_INFO:
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vss_msg->dm_info.flags = 0;
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vss_respond_to_host(0);
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return;
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default:
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vss_respond_to_host(0);
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return;
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}
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}
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icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
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| ICMSGHDRFLAG_RESPONSE;
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vmbus_sendpacket(channel, recv_buffer,
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recvlen, requestid,
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VM_PKT_DATA_INBAND, 0);
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}
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}
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int
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hv_vss_init(struct hv_util_service *srv)
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{
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int err;
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err = cn_add_callback(&vss_id, vss_name, vss_cn_callback);
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if (err)
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return err;
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recv_buffer = srv->recv_buffer;
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/*
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* When this driver loads, the user level daemon that
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* processes the host requests may not yet be running.
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* Defer processing channel callbacks until the daemon
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* has registered.
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*/
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vss_transaction.state = HVUTIL_DEVICE_INIT;
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return 0;
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}
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void hv_vss_deinit(void)
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{
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vss_transaction.state = HVUTIL_DEVICE_DYING;
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cn_del_callback(&vss_id);
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cancel_delayed_work_sync(&vss_timeout_work);
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cancel_work_sync(&vss_send_op_work);
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}
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