1 files changed, 427 insertions, 0 deletions
diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
new file mode 100644
index 000000000..922d83eb7
--- /dev/null
+++ b/drivers/hv/hv_fcopy.c
@@ -0,0 +1,427 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * An implementation of file copy service.
+ *
+ * Copyright (C) 2014, Microsoft, Inc.
+ *
+ * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/nls.h>
+#include <linux/workqueue.h>
+#include <linux/hyperv.h>
+#include <linux/sched.h>
+#include <asm/hyperv-tlfs.h>
+
+#include "hyperv_vmbus.h"
+#include "hv_utils_transport.h"
+
+#define WIN8_SRV_MAJOR		1
+#define WIN8_SRV_MINOR		1
+#define WIN8_SRV_VERSION	(WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
+
+#define FCOPY_VER_COUNT 1
+static const int fcopy_versions[] = {
+	WIN8_SRV_VERSION
+};
+
+#define FW_VER_COUNT 1
+static const int fw_versions[] = {
+	UTIL_FW_VERSION
+};
+
+/*
+ * Global state maintained for transaction that is being processed.
+ * For a class of integration services, including the "file copy service",
+ * the specified protocol is a "request/response" protocol which means that
+ * there can only be single outstanding transaction from the host at any
+ * given point in time. We use this to simplify memory management in this
+ * driver - we cache and process only one message at a time.
+ *
+ * While the request/response protocol is guaranteed by the host, we further
+ * ensure this by serializing packet processing in this driver - we do not
+ * read additional packets from the VMBUs until the current packet is fully
+ * handled.
+ */
+
+static struct {
+	int state;   /* hvutil_device_state */
+	int recv_len; /* number of bytes received. */
+	struct hv_fcopy_hdr  *fcopy_msg; /* current message */
+	struct vmbus_channel *recv_channel; /* chn we got the request */
+	u64 recv_req_id; /* request ID. */
+} fcopy_transaction;
+
+static void fcopy_respond_to_host(int error);
+static void fcopy_send_data(struct work_struct *dummy);
+static void fcopy_timeout_func(struct work_struct *dummy);
+static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
+static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
+static const char fcopy_devname[] = "vmbus/hv_fcopy";
+static u8 *recv_buffer;
+static struct hvutil_transport *hvt;
+/*
+ * This state maintains the version number registered by the daemon.
+ */
+static int dm_reg_value;
+
+static void fcopy_poll_wrapper(void *channel)
+{
+	/* Transaction is finished, reset the state here to avoid races. */
+	fcopy_transaction.state = HVUTIL_READY;
+	tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
+}
+
+static void fcopy_timeout_func(struct work_struct *dummy)
+{
+	/*
+	 * If the timer fires, the user-mode component has not responded;
+	 * process the pending transaction.
+	 */
+	fcopy_respond_to_host(HV_E_FAIL);
+	hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
+}
+
+static void fcopy_register_done(void)
+{
+	pr_debug("FCP: userspace daemon registered\n");
+	hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
+}
+
+static int fcopy_handle_handshake(u32 version)
+{
+	u32 our_ver = FCOPY_CURRENT_VERSION;
+
+	switch (version) {
+	case FCOPY_VERSION_0:
+		/* Daemon doesn't expect us to reply */
+		dm_reg_value = version;
+		break;
+	case FCOPY_VERSION_1:
+		/* Daemon expects us to reply with our own version */
+		if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
+		    fcopy_register_done))
+			return -EFAULT;
+		dm_reg_value = version;
+		break;
+	default:
+		/*
+		 * For now we will fail the registration.
+		 * If and when we have multiple versions to
+		 * deal with, we will be backward compatible.
+		 * We will add this code when needed.
+		 */
+		return -EINVAL;
+	}
+	pr_debug("FCP: userspace daemon ver. %d connected\n", version);
+	return 0;
+}
+
+static void fcopy_send_data(struct work_struct *dummy)
+{
+	struct hv_start_fcopy *smsg_out = NULL;
+	int operation = fcopy_transaction.fcopy_msg->operation;
+	struct hv_start_fcopy *smsg_in;
+	void *out_src;
+	int rc, out_len;
+
+	/*
+	 * The  strings sent from the host are encoded in
+	 * utf16; convert it to utf8 strings.
+	 * The host assures us that the utf16 strings will not exceed
+	 * the max lengths specified. We will however, reserve room
+	 * for the string terminating character - in the utf16s_utf8s()
+	 * function we limit the size of the buffer where the converted
+	 * string is placed to W_MAX_PATH -1 to guarantee
+	 * that the strings can be properly terminated!
+	 */
+
+	switch (operation) {
+	case START_FILE_COPY:
+		out_len = sizeof(struct hv_start_fcopy);
+		smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
+		if (!smsg_out)
+			return;
+
+		smsg_out->hdr.operation = operation;
+		smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
+
+		utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
+				UTF16_LITTLE_ENDIAN,
+				(__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
+
+		utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
+				UTF16_LITTLE_ENDIAN,
+				(__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
+
+		smsg_out->copy_flags = smsg_in->copy_flags;
+		smsg_out->file_size = smsg_in->file_size;
+		out_src = smsg_out;
+		break;
+
+	case WRITE_TO_FILE:
+		out_src = fcopy_transaction.fcopy_msg;
+		out_len = sizeof(struct hv_do_fcopy);
+		break;
+	default:
+		out_src = fcopy_transaction.fcopy_msg;
+		out_len = fcopy_transaction.recv_len;
+		break;
+	}
+
+	fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
+	rc = hvutil_transport_send(hvt, out_src, out_len, NULL);
+	if (rc) {
+		pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
+		if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
+			fcopy_respond_to_host(HV_E_FAIL);
+			fcopy_transaction.state = HVUTIL_READY;
+		}
+	}
+	kfree(smsg_out);
+}
+
+/*
+ * Send a response back to the host.
+ */
+
+static void
+fcopy_respond_to_host(int error)
+{
+	struct icmsg_hdr *icmsghdr;
+	u32 buf_len;
+	struct vmbus_channel *channel;
+	u64 req_id;
+
+	/*
+	 * Copy the global state for completing the transaction. Note that
+	 * only one transaction can be active at a time. This is guaranteed
+	 * by the file copy protocol implemented by the host. Furthermore,
+	 * the "transaction active" state we maintain ensures that there can
+	 * only be one active transaction at a time.
+	 */
+
+	buf_len = fcopy_transaction.recv_len;
+	channel = fcopy_transaction.recv_channel;
+	req_id = fcopy_transaction.recv_req_id;
+
+	icmsghdr = (struct icmsg_hdr *)
+			&recv_buffer[sizeof(struct vmbuspipe_hdr)];
+
+	if (channel->onchannel_callback == NULL)
+		/*
+		 * We have raced with util driver being unloaded;
+		 * silently return.
+		 */
+		return;
+
+	icmsghdr->status = error;
+	icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
+	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
+				VM_PKT_DATA_INBAND, 0);
+}
+
+void hv_fcopy_onchannelcallback(void *context)
+{
+	struct vmbus_channel *channel = context;
+	u32 recvlen;
+	u64 requestid;
+	struct hv_fcopy_hdr *fcopy_msg;
+	struct icmsg_hdr *icmsghdr;
+	int fcopy_srv_version;
+
+	if (fcopy_transaction.state > HVUTIL_READY)
+		return;
+
+	if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen, &requestid)) {
+		pr_err_ratelimited("Fcopy request received. Could not read into recv buf\n");
+		return;
+	}
+
+	if (!recvlen)
+		return;
+
+	/* Ensure recvlen is big enough to read header data */
+	if (recvlen < ICMSG_HDR) {
+		pr_err_ratelimited("Fcopy request received. Packet length too small: %d\n",
+				   recvlen);
+		return;
+	}
+
+	icmsghdr = (struct icmsg_hdr *)&recv_buffer[
+			sizeof(struct vmbuspipe_hdr)];
+
+	if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
+		if (vmbus_prep_negotiate_resp(icmsghdr,
+				recv_buffer, recvlen,
+				fw_versions, FW_VER_COUNT,
+				fcopy_versions, FCOPY_VER_COUNT,
+				NULL, &fcopy_srv_version)) {
+
+			pr_info("FCopy IC version %d.%d\n",
+				fcopy_srv_version >> 16,
+				fcopy_srv_version & 0xFFFF);
+		}
+	} else if (icmsghdr->icmsgtype == ICMSGTYPE_FCOPY) {
+		/* Ensure recvlen is big enough to contain hv_fcopy_hdr */
+		if (recvlen < ICMSG_HDR + sizeof(struct hv_fcopy_hdr)) {
+			pr_err_ratelimited("Invalid Fcopy hdr. Packet length too small: %u\n",
+					   recvlen);
+			return;
+		}
+		fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[ICMSG_HDR];
+
+		/*
+		 * Stash away this global state for completing the
+		 * transaction; note transactions are serialized.
+		 */
+
+		fcopy_transaction.recv_len = recvlen;
+		fcopy_transaction.recv_req_id = requestid;
+		fcopy_transaction.fcopy_msg = fcopy_msg;
+
+		if (fcopy_transaction.state < HVUTIL_READY) {
+			/* Userspace is not registered yet */
+			fcopy_respond_to_host(HV_E_FAIL);
+			return;
+		}
+		fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
+
+		/*
+		 * Send the information to the user-level daemon.
+		 */
+		schedule_work(&fcopy_send_work);
+		schedule_delayed_work(&fcopy_timeout_work,
+				      HV_UTIL_TIMEOUT * HZ);
+		return;
+	} else {
+		pr_err_ratelimited("Fcopy request received. Invalid msg type: %d\n",
+				   icmsghdr->icmsgtype);
+		return;
+	}
+	icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
+	vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
+			VM_PKT_DATA_INBAND, 0);
+}
+
+/* Callback when data is received from userspace */
+static int fcopy_on_msg(void *msg, int len)
+{
+	int *val = (int *)msg;
+
+	if (len != sizeof(int))
+		return -EINVAL;
+
+	if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
+		return fcopy_handle_handshake(*val);
+
+	if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
+		return -EINVAL;
+
+	/*
+	 * Complete the transaction by forwarding the result
+	 * to the host. But first, cancel the timeout.
+	 */
+	if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
+		fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
+		fcopy_respond_to_host(*val);
+		hv_poll_channel(fcopy_transaction.recv_channel,
+				fcopy_poll_wrapper);
+	}
+
+	return 0;
+}
+
+static void fcopy_on_reset(void)
+{
+	/*
+	 * The daemon has exited; reset the state.
+	 */
+	fcopy_transaction.state = HVUTIL_DEVICE_INIT;
+
+	if (cancel_delayed_work_sync(&fcopy_timeout_work))
+		fcopy_respond_to_host(HV_E_FAIL);
+}
+
+int hv_fcopy_init(struct hv_util_service *srv)
+{
+	recv_buffer = srv->recv_buffer;
+	fcopy_transaction.recv_channel = srv->channel;
+	fcopy_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
+
+	/*
+	 * When this driver loads, the user level daemon that
+	 * processes the host requests may not yet be running.
+	 * Defer processing channel callbacks until the daemon
+	 * has registered.
+	 */
+	fcopy_transaction.state = HVUTIL_DEVICE_INIT;
+
+	hvt = hvutil_transport_init(fcopy_devname, 0, 0,
+				    fcopy_on_msg, fcopy_on_reset);
+	if (!hvt)
+		return -EFAULT;
+
+	return 0;
+}
+
+static void hv_fcopy_cancel_work(void)
+{
+	cancel_delayed_work_sync(&fcopy_timeout_work);
+	cancel_work_sync(&fcopy_send_work);
+}
+
+int hv_fcopy_pre_suspend(void)
+{
+	struct vmbus_channel *channel = fcopy_transaction.recv_channel;
+	struct hv_fcopy_hdr *fcopy_msg;
+
+	/*
+	 * Fake a CANCEL_FCOPY message for the user space daemon in case the
+	 * daemon is in the middle of copying some file. It doesn't matter if
+	 * there is already a message pending to be delivered to the user
+	 * space since we force fcopy_transaction.state to be HVUTIL_READY, so
+	 * the user space daemon's write() will fail with EINVAL (see
+	 * fcopy_on_msg()), and the daemon will reset the device by closing
+	 * and re-opening it.
+	 */
+	fcopy_msg = kzalloc(sizeof(*fcopy_msg), GFP_KERNEL);
+	if (!fcopy_msg)
+		return -ENOMEM;
+
+	tasklet_disable(&channel->callback_event);
+
+	fcopy_msg->operation = CANCEL_FCOPY;
+
+	hv_fcopy_cancel_work();
+
+	/* We don't care about the return value. */
+	hvutil_transport_send(hvt, fcopy_msg, sizeof(*fcopy_msg), NULL);
+
+	kfree(fcopy_msg);
+
+	fcopy_transaction.state = HVUTIL_READY;
+
+	/* tasklet_enable() will be called in hv_fcopy_pre_resume(). */
+	return 0;
+}
+
+int hv_fcopy_pre_resume(void)
+{
+	struct vmbus_channel *channel = fcopy_transaction.recv_channel;
+
+	tasklet_enable(&channel->callback_event);
+
+	return 0;
+}
+
+void hv_fcopy_deinit(void)
+{
+	fcopy_transaction.state = HVUTIL_DEVICE_DYING;
+
+	hv_fcopy_cancel_work();
+
+	hvutil_transport_destroy(hvt);
+}