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427 lines
12 KiB
427 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* An implementation of file copy service. |
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* |
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* Copyright (C) 2014, Microsoft, Inc. |
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* |
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* Author : K. Y. Srinivasan <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/nls.h> |
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#include <linux/workqueue.h> |
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#include <linux/hyperv.h> |
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#include <linux/sched.h> |
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#include <asm/hyperv-tlfs.h> |
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#include "hyperv_vmbus.h" |
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#include "hv_utils_transport.h" |
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#define WIN8_SRV_MAJOR 1 |
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#define WIN8_SRV_MINOR 1 |
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#define WIN8_SRV_VERSION (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR) |
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#define FCOPY_VER_COUNT 1 |
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static const int fcopy_versions[] = { |
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WIN8_SRV_VERSION |
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}; |
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#define FW_VER_COUNT 1 |
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static const int fw_versions[] = { |
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UTIL_FW_VERSION |
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}; |
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/* |
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* Global state maintained for transaction that is being processed. |
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* For a class of integration services, including the "file copy service", |
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* the specified protocol is a "request/response" protocol which means that |
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* there can only be single outstanding transaction from the host at any |
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* given point in time. We use this to simplify memory management in this |
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* driver - we cache and process 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 hv_fcopy_hdr *fcopy_msg; /* current message */ |
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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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} fcopy_transaction; |
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static void fcopy_respond_to_host(int error); |
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static void fcopy_send_data(struct work_struct *dummy); |
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static void fcopy_timeout_func(struct work_struct *dummy); |
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static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func); |
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static DECLARE_WORK(fcopy_send_work, fcopy_send_data); |
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static const char fcopy_devname[] = "vmbus/hv_fcopy"; |
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static u8 *recv_buffer; |
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static struct hvutil_transport *hvt; |
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/* |
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* This state maintains the version number registered by the daemon. |
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*/ |
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static int dm_reg_value; |
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static void fcopy_poll_wrapper(void *channel) |
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{ |
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/* Transaction is finished, reset the state here to avoid races. */ |
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fcopy_transaction.state = HVUTIL_READY; |
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tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event); |
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} |
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static void fcopy_timeout_func(struct work_struct *dummy) |
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{ |
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/* |
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* If the timer fires, the user-mode component has not responded; |
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* process the pending transaction. |
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*/ |
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fcopy_respond_to_host(HV_E_FAIL); |
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hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper); |
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} |
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static void fcopy_register_done(void) |
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{ |
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pr_debug("FCP: userspace daemon registered\n"); |
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hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper); |
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} |
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static int fcopy_handle_handshake(u32 version) |
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{ |
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u32 our_ver = FCOPY_CURRENT_VERSION; |
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switch (version) { |
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case FCOPY_VERSION_0: |
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/* Daemon doesn't expect us to reply */ |
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dm_reg_value = version; |
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break; |
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case FCOPY_VERSION_1: |
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/* Daemon expects us to reply with our own version */ |
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if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver), |
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fcopy_register_done)) |
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return -EFAULT; |
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dm_reg_value = version; |
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break; |
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default: |
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/* |
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* For now we will fail the registration. |
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* If and when we have multiple versions to |
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* deal with, we will be backward compatible. |
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* We will add this code when needed. |
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*/ |
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return -EINVAL; |
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} |
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pr_debug("FCP: userspace daemon ver. %d connected\n", version); |
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return 0; |
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} |
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static void fcopy_send_data(struct work_struct *dummy) |
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{ |
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struct hv_start_fcopy *smsg_out = NULL; |
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int operation = fcopy_transaction.fcopy_msg->operation; |
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struct hv_start_fcopy *smsg_in; |
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void *out_src; |
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int rc, out_len; |
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/* |
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* The strings sent from the host are encoded in |
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* in utf16; convert it to utf8 strings. |
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* The host assures us that the utf16 strings will not exceed |
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* the max lengths specified. We will however, reserve room |
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* for the string terminating character - in the utf16s_utf8s() |
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* function we limit the size of the buffer where the converted |
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* string is placed to W_MAX_PATH -1 to guarantee |
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* that the strings can be properly terminated! |
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*/ |
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switch (operation) { |
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case START_FILE_COPY: |
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out_len = sizeof(struct hv_start_fcopy); |
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smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL); |
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if (!smsg_out) |
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return; |
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smsg_out->hdr.operation = operation; |
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smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg; |
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utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH, |
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UTF16_LITTLE_ENDIAN, |
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(__u8 *)&smsg_out->file_name, W_MAX_PATH - 1); |
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utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH, |
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UTF16_LITTLE_ENDIAN, |
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(__u8 *)&smsg_out->path_name, W_MAX_PATH - 1); |
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smsg_out->copy_flags = smsg_in->copy_flags; |
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smsg_out->file_size = smsg_in->file_size; |
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out_src = smsg_out; |
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break; |
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case WRITE_TO_FILE: |
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out_src = fcopy_transaction.fcopy_msg; |
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out_len = sizeof(struct hv_do_fcopy); |
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break; |
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default: |
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out_src = fcopy_transaction.fcopy_msg; |
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out_len = fcopy_transaction.recv_len; |
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break; |
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} |
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fcopy_transaction.state = HVUTIL_USERSPACE_REQ; |
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rc = hvutil_transport_send(hvt, out_src, out_len, NULL); |
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if (rc) { |
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pr_debug("FCP: failed to communicate to the daemon: %d\n", rc); |
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if (cancel_delayed_work_sync(&fcopy_timeout_work)) { |
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fcopy_respond_to_host(HV_E_FAIL); |
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fcopy_transaction.state = HVUTIL_READY; |
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} |
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} |
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kfree(smsg_out); |
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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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fcopy_respond_to_host(int error) |
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{ |
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struct icmsg_hdr *icmsghdr; |
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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. This is guaranteed |
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* by the file copy protocol implemented by the host. Furthermore, |
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* the "transaction active" state we maintain ensures that there can |
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* only be one active transaction at a time. |
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*/ |
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buf_len = fcopy_transaction.recv_len; |
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channel = fcopy_transaction.recv_channel; |
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req_id = fcopy_transaction.recv_req_id; |
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icmsghdr = (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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icmsghdr->status = error; |
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icmsghdr->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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void hv_fcopy_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_fcopy_hdr *fcopy_msg; |
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struct icmsg_hdr *icmsghdr; |
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int fcopy_srv_version; |
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if (fcopy_transaction.state > HVUTIL_READY) |
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return; |
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if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen, &requestid)) { |
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pr_err_ratelimited("Fcopy request received. Could not read into recv buf\n"); |
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return; |
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} |
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if (!recvlen) |
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return; |
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/* Ensure recvlen is big enough to read header data */ |
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if (recvlen < ICMSG_HDR) { |
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pr_err_ratelimited("Fcopy request received. Packet length too small: %d\n", |
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recvlen); |
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return; |
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} |
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icmsghdr = (struct icmsg_hdr *)&recv_buffer[ |
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sizeof(struct vmbuspipe_hdr)]; |
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if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) { |
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if (vmbus_prep_negotiate_resp(icmsghdr, |
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recv_buffer, recvlen, |
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fw_versions, FW_VER_COUNT, |
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fcopy_versions, FCOPY_VER_COUNT, |
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NULL, &fcopy_srv_version)) { |
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pr_info("FCopy IC version %d.%d\n", |
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fcopy_srv_version >> 16, |
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fcopy_srv_version & 0xFFFF); |
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} |
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} else if (icmsghdr->icmsgtype == ICMSGTYPE_FCOPY) { |
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/* Ensure recvlen is big enough to contain hv_fcopy_hdr */ |
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if (recvlen < ICMSG_HDR + sizeof(struct hv_fcopy_hdr)) { |
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pr_err_ratelimited("Invalid Fcopy hdr. Packet length too small: %u\n", |
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recvlen); |
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return; |
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} |
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fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[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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fcopy_transaction.recv_len = recvlen; |
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fcopy_transaction.recv_req_id = requestid; |
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fcopy_transaction.fcopy_msg = fcopy_msg; |
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if (fcopy_transaction.state < HVUTIL_READY) { |
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/* Userspace is not registered yet */ |
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fcopy_respond_to_host(HV_E_FAIL); |
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return; |
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} |
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fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED; |
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/* |
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* Send the information to the user-level daemon. |
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*/ |
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schedule_work(&fcopy_send_work); |
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schedule_delayed_work(&fcopy_timeout_work, |
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HV_UTIL_TIMEOUT * HZ); |
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return; |
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} else { |
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pr_err_ratelimited("Fcopy request received. Invalid msg type: %d\n", |
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icmsghdr->icmsgtype); |
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return; |
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} |
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icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; |
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vmbus_sendpacket(channel, recv_buffer, recvlen, requestid, |
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VM_PKT_DATA_INBAND, 0); |
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} |
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/* Callback when data is received from userspace */ |
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static int fcopy_on_msg(void *msg, int len) |
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{ |
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int *val = (int *)msg; |
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if (len != sizeof(int)) |
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return -EINVAL; |
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if (fcopy_transaction.state == HVUTIL_DEVICE_INIT) |
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return fcopy_handle_handshake(*val); |
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if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ) |
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return -EINVAL; |
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/* |
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* Complete the transaction by forwarding the result |
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* to the host. But first, cancel the timeout. |
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*/ |
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if (cancel_delayed_work_sync(&fcopy_timeout_work)) { |
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fcopy_transaction.state = HVUTIL_USERSPACE_RECV; |
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fcopy_respond_to_host(*val); |
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hv_poll_channel(fcopy_transaction.recv_channel, |
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fcopy_poll_wrapper); |
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} |
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return 0; |
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} |
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static void fcopy_on_reset(void) |
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{ |
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/* |
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* The daemon has exited; reset the state. |
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*/ |
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fcopy_transaction.state = HVUTIL_DEVICE_INIT; |
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if (cancel_delayed_work_sync(&fcopy_timeout_work)) |
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fcopy_respond_to_host(HV_E_FAIL); |
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} |
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int hv_fcopy_init(struct hv_util_service *srv) |
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{ |
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recv_buffer = srv->recv_buffer; |
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fcopy_transaction.recv_channel = srv->channel; |
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fcopy_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2; |
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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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fcopy_transaction.state = HVUTIL_DEVICE_INIT; |
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hvt = hvutil_transport_init(fcopy_devname, 0, 0, |
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fcopy_on_msg, fcopy_on_reset); |
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if (!hvt) |
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return -EFAULT; |
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return 0; |
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} |
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static void hv_fcopy_cancel_work(void) |
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{ |
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cancel_delayed_work_sync(&fcopy_timeout_work); |
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cancel_work_sync(&fcopy_send_work); |
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} |
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int hv_fcopy_pre_suspend(void) |
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{ |
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struct vmbus_channel *channel = fcopy_transaction.recv_channel; |
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struct hv_fcopy_hdr *fcopy_msg; |
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/* |
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* Fake a CANCEL_FCOPY message for the user space daemon in case the |
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* daemon is in the middle of copying some file. It doesn't matter if |
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* there is already a message pending to be delivered to the user |
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* space since we force fcopy_transaction.state to be HVUTIL_READY, so |
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* the user space daemon's write() will fail with EINVAL (see |
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* fcopy_on_msg()), and the daemon will reset the device by closing |
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* and re-opening it. |
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*/ |
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fcopy_msg = kzalloc(sizeof(*fcopy_msg), GFP_KERNEL); |
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if (!fcopy_msg) |
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return -ENOMEM; |
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tasklet_disable(&channel->callback_event); |
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fcopy_msg->operation = CANCEL_FCOPY; |
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hv_fcopy_cancel_work(); |
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/* We don't care about the return value. */ |
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hvutil_transport_send(hvt, fcopy_msg, sizeof(*fcopy_msg), NULL); |
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kfree(fcopy_msg); |
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fcopy_transaction.state = HVUTIL_READY; |
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/* tasklet_enable() will be called in hv_fcopy_pre_resume(). */ |
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return 0; |
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} |
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int hv_fcopy_pre_resume(void) |
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{ |
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struct vmbus_channel *channel = fcopy_transaction.recv_channel; |
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tasklet_enable(&channel->callback_event); |
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return 0; |
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} |
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void hv_fcopy_deinit(void) |
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{ |
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fcopy_transaction.state = HVUTIL_DEVICE_DYING; |
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hv_fcopy_cancel_work(); |
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hvutil_transport_destroy(hvt); |
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}
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