drivers/gpu/drm/vmwgfx/vmwgfx_msg.c - arm/linux - Git at Google

 /*
  * Copyright © 2016 VMware, Inc., Palo Alto, CA., USA
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sub license, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * The above copyright notice and this permission notice (including the
  * next paragraph) shall be included in all copies or substantial portions
  * of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  *
  */


 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/frame.h>
 #include <asm/hypervisor.h>
 #include <drm/drmP.h>
 #include "vmwgfx_msg.h"


 #define MESSAGE_STATUS_SUCCESS  0x0001
 #define MESSAGE_STATUS_DORECV   0x0002
 #define MESSAGE_STATUS_CPT      0x0010
 #define MESSAGE_STATUS_HB       0x0080

 #define RPCI_PROTOCOL_NUM       0x49435052
 #define GUESTMSG_FLAG_COOKIE    0x80000000

 #define RETRIES                 3

 #define VMW_HYPERVISOR_MAGIC    0x564D5868
 #define VMW_HYPERVISOR_PORT     0x5658
 #define VMW_HYPERVISOR_HB_PORT  0x5659

 #define VMW_PORT_CMD_MSG        30
 #define VMW_PORT_CMD_HB_MSG     0
 #define VMW_PORT_CMD_OPEN_CHANNEL  (MSG_TYPE_OPEN << 16 | VMW_PORT_CMD_MSG)
 #define VMW_PORT_CMD_CLOSE_CHANNEL (MSG_TYPE_CLOSE << 16 | VMW_PORT_CMD_MSG)
 #define VMW_PORT_CMD_SENDSIZE   (MSG_TYPE_SENDSIZE << 16 | VMW_PORT_CMD_MSG)
 #define VMW_PORT_CMD_RECVSIZE   (MSG_TYPE_RECVSIZE << 16 | VMW_PORT_CMD_MSG)
 #define VMW_PORT_CMD_RECVSTATUS (MSG_TYPE_RECVSTATUS << 16 | VMW_PORT_CMD_MSG)

 #define HIGH_WORD(X) ((X & 0xFFFF0000) >> 16)

 static u32 vmw_msg_enabled = 1;

 enum rpc_msg_type {
 	MSG_TYPE_OPEN,
 	MSG_TYPE_SENDSIZE,
 	MSG_TYPE_SENDPAYLOAD,
 	MSG_TYPE_RECVSIZE,
 	MSG_TYPE_RECVPAYLOAD,
 	MSG_TYPE_RECVSTATUS,
 	MSG_TYPE_CLOSE,
 };

 struct rpc_channel {
 	u16 channel_id;
 	u32 cookie_high;
 	u32 cookie_low;
 };


 /**
  * vmw_open_channel
  *
  * @channel: RPC channel
  * @protocol:
  *
  * Returns: 0 on success
  */
 static int vmw_open_channel(struct rpc_channel *channel, unsigned int protocol)
 {
 	unsigned long eax, ebx, ecx, edx, si = 0, di = 0;

 	VMW_PORT(VMW_PORT_CMD_OPEN_CHANNEL,
 		(protocol | GUESTMSG_FLAG_COOKIE), si, di,
 		VMW_HYPERVISOR_PORT,
 		VMW_HYPERVISOR_MAGIC,
 		eax, ebx, ecx, edx, si, di);

 	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
 		return -EINVAL;

 	channel->channel_id  = HIGH_WORD(edx);
 	channel->cookie_high = si;
 	channel->cookie_low  = di;

 	return 0;
 }


 /**
  * vmw_close_channel
  *
  * @channel: RPC channel
  *
  * Returns: 0 on success
  */
 static int vmw_close_channel(struct rpc_channel *channel)
 {
 	unsigned long eax, ebx, ecx, edx, si, di;

 	/* Set up additional parameters */
 	si  = channel->cookie_high;
 	di  = channel->cookie_low;

 	VMW_PORT(VMW_PORT_CMD_CLOSE_CHANNEL,
 		0, si, di,
 		(VMW_HYPERVISOR_PORT | (channel->channel_id << 16)),
 		VMW_HYPERVISOR_MAGIC,
 		eax, ebx, ecx, edx, si, di);

 	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
 		return -EINVAL;

 	return 0;
 }


 /**
  * vmw_send_msg: Sends a message to the host
  *
  * @channel: RPC channel
  * @logmsg: NULL terminated string
  *
  * Returns: 0 on success
  */
 static int vmw_send_msg(struct rpc_channel *channel, const char *msg)
 {
 	unsigned long eax, ebx, ecx, edx, si, di, bp;
 	size_t msg_len = strlen(msg);
 	int retries = 0;


 	while (retries < RETRIES) {
 		retries++;

 		/* Set up additional parameters */
 		si  = channel->cookie_high;
 		di  = channel->cookie_low;

 		VMW_PORT(VMW_PORT_CMD_SENDSIZE,
 			msg_len, si, di,
 			VMW_HYPERVISOR_PORT | (channel->channel_id << 16),
 			VMW_HYPERVISOR_MAGIC,
 			eax, ebx, ecx, edx, si, di);

 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0 ||
 		    (HIGH_WORD(ecx) & MESSAGE_STATUS_HB) == 0) {
 			/* Expected success + high-bandwidth. Give up. */
 			return -EINVAL;
 		}

 		/* Send msg */
 		si  = (uintptr_t) msg;
 		di  = channel->cookie_low;
 		bp  = channel->cookie_high;

 		VMW_PORT_HB_OUT(
 			(MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
 			msg_len, si, di,
 			VMW_HYPERVISOR_HB_PORT | (channel->channel_id << 16),
 			VMW_HYPERVISOR_MAGIC, bp,
 			eax, ebx, ecx, edx, si, di);

 		if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) != 0) {
 			return 0;
 		} else if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) {
 			/* A checkpoint occurred. Retry. */
 			continue;
 		} else {
 			break;
 		}
 	}

 	return -EINVAL;
 }
 STACK_FRAME_NON_STANDARD(vmw_send_msg);


 /**
  * vmw_recv_msg: Receives a message from the host
  *
  * Note:  It is the caller's responsibility to call kfree() on msg.
  *
  * @channel:  channel opened by vmw_open_channel
  * @msg:  [OUT] message received from the host
  * @msg_len: message length
  */
 static int vmw_recv_msg(struct rpc_channel *channel, void **msg,
 			size_t *msg_len)
 {
 	unsigned long eax, ebx, ecx, edx, si, di, bp;
 	char *reply;
 	size_t reply_len;
 	int retries = 0;


 	*msg_len = 0;
 	*msg = NULL;

 	while (retries < RETRIES) {
 		retries++;

 		/* Set up additional parameters */
 		si  = channel->cookie_high;
 		di  = channel->cookie_low;

 		VMW_PORT(VMW_PORT_CMD_RECVSIZE,
 			0, si, di,
 			(VMW_HYPERVISOR_PORT | (channel->channel_id << 16)),
 			VMW_HYPERVISOR_MAGIC,
 			eax, ebx, ecx, edx, si, di);

 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0 ||
 		    (HIGH_WORD(ecx) & MESSAGE_STATUS_HB) == 0) {
 			DRM_ERROR("Failed to get reply size\n");
 			return -EINVAL;
 		}

 		/* No reply available.  This is okay. */
 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_DORECV) == 0)
 			return 0;

 		reply_len = ebx;
 		reply     = kzalloc(reply_len + 1, GFP_KERNEL);
 		if (reply == NULL) {
 			DRM_ERROR("Cannot allocate memory for reply\n");
 			return -ENOMEM;
 		}


 		/* Receive buffer */
 		si  = channel->cookie_high;
 		di  = (uintptr_t) reply;
 		bp  = channel->cookie_low;

 		VMW_PORT_HB_IN(
 			(MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
 			reply_len, si, di,
 			VMW_HYPERVISOR_HB_PORT | (channel->channel_id << 16),
 			VMW_HYPERVISOR_MAGIC, bp,
 			eax, ebx, ecx, edx, si, di);

 		if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) {
 			kfree(reply);

 			if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) {
 				/* A checkpoint occurred. Retry. */
 				continue;
 			}

 			return -EINVAL;
 		}

 		reply[reply_len] = '\0';


 		/* Ack buffer */
 		si  = channel->cookie_high;
 		di  = channel->cookie_low;

 		VMW_PORT(VMW_PORT_CMD_RECVSTATUS,
 			MESSAGE_STATUS_SUCCESS, si, di,
 			(VMW_HYPERVISOR_PORT | (channel->channel_id << 16)),
 			VMW_HYPERVISOR_MAGIC,
 			eax, ebx, ecx, edx, si, di);

 		if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
 			kfree(reply);

 			if ((HIGH_WORD(ecx) & MESSAGE_STATUS_CPT) != 0) {
 				/* A checkpoint occurred. Retry. */
 				continue;
 			}

 			return -EINVAL;
 		}

 		break;
 	}

 	if (retries == RETRIES)
 		return -EINVAL;

 	*msg_len = reply_len;
 	*msg     = reply;

 	return 0;
 }
 STACK_FRAME_NON_STANDARD(vmw_recv_msg);


 /**
  * vmw_host_get_guestinfo: Gets a GuestInfo parameter
  *
  * Gets the value of a  GuestInfo.* parameter.  The value returned will be in
  * a string, and it is up to the caller to post-process.
  *
  * @guest_info_param:  Parameter to get, e.g. GuestInfo.svga.gl3
  * @buffer: if NULL, *reply_len will contain reply size.
  * @length: size of the reply_buf.  Set to size of reply upon return
  *
  * Returns: 0 on success
  */
 int vmw_host_get_guestinfo(const char *guest_info_param,
 			   char *buffer, size_t *length)
 {
 	struct rpc_channel channel;
 	char *msg, *reply = NULL;
 	size_t msg_len, reply_len = 0;
 	int ret = 0;


 	if (!vmw_msg_enabled)
 		return -ENODEV;

 	if (!guest_info_param || !length)
 		return -EINVAL;

 	msg_len = strlen(guest_info_param) + strlen("info-get ") + 1;
 	msg = kzalloc(msg_len, GFP_KERNEL);
 	if (msg == NULL) {
 		DRM_ERROR("Cannot allocate memory to get %s", guest_info_param);
 		return -ENOMEM;
 	}

 	sprintf(msg, "info-get %s", guest_info_param);

 	if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM) ||
 	    vmw_send_msg(&channel, msg) ||
 	    vmw_recv_msg(&channel, (void *) &reply, &reply_len) ||
 	    vmw_close_channel(&channel)) {
 		DRM_ERROR("Failed to get %s", guest_info_param);

 		ret = -EINVAL;
 	}

 	if (buffer && reply && reply_len > 0) {
 		/* Remove reply code, which are the first 2 characters of
 		 * the reply
 		 */
 		reply_len = max(reply_len - 2, (size_t) 0);
 		reply_len = min(reply_len, *length);

 		if (reply_len > 0)
 			memcpy(buffer, reply + 2, reply_len);
 	}

 	*length = reply_len;

 	kfree(reply);
 	kfree(msg);

 	return ret;
 }


 /**
  * vmw_host_log: Sends a log message to the host
  *
  * @log: NULL terminated string
  *
  * Returns: 0 on success
  */
 int vmw_host_log(const char *log)
 {
 	struct rpc_channel channel;
 	char *msg;
 	int msg_len;
 	int ret = 0;


 	if (!vmw_msg_enabled)
 		return -ENODEV;

 	if (!log)
 		return ret;

 	msg_len = strlen(log) + strlen("log ") + 1;
 	msg = kzalloc(msg_len, GFP_KERNEL);
 	if (msg == NULL) {
 		DRM_ERROR("Cannot allocate memory for log message\n");
 		return -ENOMEM;
 	}

 	sprintf(msg, "log %s", log);

 	if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM) ||
 	    vmw_send_msg(&channel, msg) ||
 	    vmw_close_channel(&channel)) {
 		DRM_ERROR("Failed to send log\n");

 		ret = -EINVAL;
 	}

 	kfree(msg);

 	return ret;
 }
	/*
	* Copyright © 2016 VMware, Inc., Palo Alto, CA., USA
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sub license, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* The above copyright notice and this permission notice (including the
	* next paragraph) shall be included in all copies or substantial portions
	* of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
	* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
	* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
	* USE OR OTHER DEALINGS IN THE SOFTWARE.
	*
	*/


	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/frame.h>
	#include <asm/hypervisor.h>
	#include <drm/drmP.h>
	#include "vmwgfx_msg.h"


	#define MESSAGE_STATUS_SUCCESS 0x0001
	#define MESSAGE_STATUS_DORECV 0x0002
	#define MESSAGE_STATUS_CPT 0x0010
	#define MESSAGE_STATUS_HB 0x0080

	#define RPCI_PROTOCOL_NUM 0x49435052
	#define GUESTMSG_FLAG_COOKIE 0x80000000

	#define RETRIES 3

	#define VMW_HYPERVISOR_MAGIC 0x564D5868
	#define VMW_HYPERVISOR_PORT 0x5658
	#define VMW_HYPERVISOR_HB_PORT 0x5659

	#define VMW_PORT_CMD_MSG 30
	#define VMW_PORT_CMD_HB_MSG 0
	#define VMW_PORT_CMD_OPEN_CHANNEL (MSG_TYPE_OPEN << 16 \| VMW_PORT_CMD_MSG)
	#define VMW_PORT_CMD_CLOSE_CHANNEL (MSG_TYPE_CLOSE << 16 \| VMW_PORT_CMD_MSG)
	#define VMW_PORT_CMD_SENDSIZE (MSG_TYPE_SENDSIZE << 16 \| VMW_PORT_CMD_MSG)
	#define VMW_PORT_CMD_RECVSIZE (MSG_TYPE_RECVSIZE << 16 \| VMW_PORT_CMD_MSG)
	#define VMW_PORT_CMD_RECVSTATUS (MSG_TYPE_RECVSTATUS << 16 \| VMW_PORT_CMD_MSG)

	#define HIGH_WORD(X) ((X & 0xFFFF0000) >> 16)

	static u32 vmw_msg_enabled = 1;

	enum rpc_msg_type {
	MSG_TYPE_OPEN,
	MSG_TYPE_SENDSIZE,
	MSG_TYPE_SENDPAYLOAD,
	MSG_TYPE_RECVSIZE,
	MSG_TYPE_RECVPAYLOAD,
	MSG_TYPE_RECVSTATUS,
	MSG_TYPE_CLOSE,
	};

	struct rpc_channel {
	u16 channel_id;
	u32 cookie_high;
	u32 cookie_low;
	};



	/**
	* vmw_open_channel
	*
	* @channel: RPC channel
	* @protocol:
	*
	* Returns: 0 on success
	*/
	static int vmw_open_channel(struct rpc_channel *channel, unsigned int protocol)
	{
	unsigned long eax, ebx, ecx, edx, si = 0, di = 0;

	VMW_PORT(VMW_PORT_CMD_OPEN_CHANNEL,
	(protocol \| GUESTMSG_FLAG_COOKIE), si, di,
	VMW_HYPERVISOR_PORT,
	VMW_HYPERVISOR_MAGIC,
	eax, ebx, ecx, edx, si, di);

	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
	return -EINVAL;

	channel->channel_id = HIGH_WORD(edx);
	channel->cookie_high = si;
	channel->cookie_low = di;

	return 0;
	}



	/**
	* vmw_close_channel
	*
	* @channel: RPC channel
	*
	* Returns: 0 on success
	*/
	static int vmw_close_channel(struct rpc_channel *channel)
	{
	unsigned long eax, ebx, ecx, edx, si, di;

	/* Set up additional parameters */
	si = channel->cookie_high;
	di = channel->cookie_low;

	VMW_PORT(VMW_PORT_CMD_CLOSE_CHANNEL,
	0, si, di,
	(VMW_HYPERVISOR_PORT \| (channel->channel_id << 16)),
	VMW_HYPERVISOR_MAGIC,
	eax, ebx, ecx, edx, si, di);

	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
	return -EINVAL;

	return 0;
	}



	/**
	* vmw_send_msg: Sends a message to the host
	*
	* @channel: RPC channel
	* @logmsg: NULL terminated string
	*
	* Returns: 0 on success
	*/
	static int vmw_send_msg(struct rpc_channel channel, const char msg)
	{
	unsigned long eax, ebx, ecx, edx, si, di, bp;
	size_t msg_len = strlen(msg);
	int retries = 0;


	while (retries < RETRIES) {
	retries++;

	/* Set up additional parameters */
	si = channel->cookie_high;
	di = channel->cookie_low;

	VMW_PORT(VMW_PORT_CMD_SENDSIZE,
	msg_len, si, di,
	VMW_HYPERVISOR_PORT \| (channel->channel_id << 16),
	VMW_HYPERVISOR_MAGIC,
	eax, ebx, ecx, edx, si, di);

	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0 \|\|
	(HIGH_WORD(ecx) & MESSAGE_STATUS_HB) == 0) {
	/* Expected success + high-bandwidth. Give up. */
	return -EINVAL;
	}

	/* Send msg */
	si = (uintptr_t) msg;
	di = channel->cookie_low;
	bp = channel->cookie_high;

	VMW_PORT_HB_OUT(
	(MESSAGE_STATUS_SUCCESS << 16) \| VMW_PORT_CMD_HB_MSG,
	msg_len, si, di,
	VMW_HYPERVISOR_HB_PORT \| (channel->channel_id << 16),
	VMW_HYPERVISOR_MAGIC, bp,
	eax, ebx, ecx, edx, si, di);

	if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) != 0) {
	return 0;
	} else if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) {
	/* A checkpoint occurred. Retry. */
	continue;
	} else {
	break;
	}
	}

	return -EINVAL;
	}
	STACK_FRAME_NON_STANDARD(vmw_send_msg);


	/**
	* vmw_recv_msg: Receives a message from the host
	*
	* Note: It is the caller's responsibility to call kfree() on msg.
	*
	* @channel: channel opened by vmw_open_channel
	* @msg: [OUT] message received from the host
	* @msg_len: message length
	*/
	static int vmw_recv_msg(struct rpc_channel channel, void *msg,
	size_t *msg_len)
	{
	unsigned long eax, ebx, ecx, edx, si, di, bp;
	char *reply;
	size_t reply_len;
	int retries = 0;


	*msg_len = 0;
	*msg = NULL;

	while (retries < RETRIES) {
	retries++;

	/* Set up additional parameters */
	si = channel->cookie_high;
	di = channel->cookie_low;

	VMW_PORT(VMW_PORT_CMD_RECVSIZE,
	0, si, di,
	(VMW_HYPERVISOR_PORT \| (channel->channel_id << 16)),
	VMW_HYPERVISOR_MAGIC,
	eax, ebx, ecx, edx, si, di);

	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0 \|\|
	(HIGH_WORD(ecx) & MESSAGE_STATUS_HB) == 0) {
	DRM_ERROR("Failed to get reply size\n");
	return -EINVAL;
	}

	/* No reply available. This is okay. */
	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_DORECV) == 0)
	return 0;

	reply_len = ebx;
	reply = kzalloc(reply_len + 1, GFP_KERNEL);
	if (reply == NULL) {
	DRM_ERROR("Cannot allocate memory for reply\n");
	return -ENOMEM;
	}


	/* Receive buffer */
	si = channel->cookie_high;
	di = (uintptr_t) reply;
	bp = channel->cookie_low;

	VMW_PORT_HB_IN(
	(MESSAGE_STATUS_SUCCESS << 16) \| VMW_PORT_CMD_HB_MSG,
	reply_len, si, di,
	VMW_HYPERVISOR_HB_PORT \| (channel->channel_id << 16),
	VMW_HYPERVISOR_MAGIC, bp,
	eax, ebx, ecx, edx, si, di);

	if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) {
	kfree(reply);

	if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) {
	/* A checkpoint occurred. Retry. */
	continue;
	}

	return -EINVAL;
	}

	reply[reply_len] = '\0';


	/* Ack buffer */
	si = channel->cookie_high;
	di = channel->cookie_low;

	VMW_PORT(VMW_PORT_CMD_RECVSTATUS,
	MESSAGE_STATUS_SUCCESS, si, di,
	(VMW_HYPERVISOR_PORT \| (channel->channel_id << 16)),
	VMW_HYPERVISOR_MAGIC,
	eax, ebx, ecx, edx, si, di);

	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
	kfree(reply);

	if ((HIGH_WORD(ecx) & MESSAGE_STATUS_CPT) != 0) {
	/* A checkpoint occurred. Retry. */
	continue;
	}

	return -EINVAL;
	}

	break;
	}

	if (retries == RETRIES)
	return -EINVAL;

	*msg_len = reply_len;
	*msg = reply;

	return 0;
	}
	STACK_FRAME_NON_STANDARD(vmw_recv_msg);


	/**
	* vmw_host_get_guestinfo: Gets a GuestInfo parameter
	*
	* Gets the value of a GuestInfo.* parameter. The value returned will be in
	* a string, and it is up to the caller to post-process.
	*
	* @guest_info_param: Parameter to get, e.g. GuestInfo.svga.gl3
	* @buffer: if NULL, *reply_len will contain reply size.
	* @length: size of the reply_buf. Set to size of reply upon return
	*
	* Returns: 0 on success
	*/
	int vmw_host_get_guestinfo(const char *guest_info_param,
	char buffer, size_t length)
	{
	struct rpc_channel channel;
	char msg, reply = NULL;
	size_t msg_len, reply_len = 0;
	int ret = 0;


	if (!vmw_msg_enabled)
	return -ENODEV;

	if (!guest_info_param \|\| !length)
	return -EINVAL;

	msg_len = strlen(guest_info_param) + strlen("info-get ") + 1;
	msg = kzalloc(msg_len, GFP_KERNEL);
	if (msg == NULL) {
	DRM_ERROR("Cannot allocate memory to get %s", guest_info_param);
	return -ENOMEM;
	}

	sprintf(msg, "info-get %s", guest_info_param);

	if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM) \|\|
	vmw_send_msg(&channel, msg) \|\|
	vmw_recv_msg(&channel, (void *) &reply, &reply_len) \|\|
	vmw_close_channel(&channel)) {
	DRM_ERROR("Failed to get %s", guest_info_param);

	ret = -EINVAL;
	}

	if (buffer && reply && reply_len > 0) {
	/* Remove reply code, which are the first 2 characters of
	* the reply
	*/
	reply_len = max(reply_len - 2, (size_t) 0);
	reply_len = min(reply_len, *length);

	if (reply_len > 0)
	memcpy(buffer, reply + 2, reply_len);
	}

	*length = reply_len;

	kfree(reply);
	kfree(msg);

	return ret;
	}



	/**
	* vmw_host_log: Sends a log message to the host
	*
	* @log: NULL terminated string
	*
	* Returns: 0 on success
	*/
	int vmw_host_log(const char *log)
	{
	struct rpc_channel channel;
	char *msg;
	int msg_len;
	int ret = 0;


	if (!vmw_msg_enabled)
	return -ENODEV;

	if (!log)
	return ret;

	msg_len = strlen(log) + strlen("log ") + 1;
	msg = kzalloc(msg_len, GFP_KERNEL);
	if (msg == NULL) {
	DRM_ERROR("Cannot allocate memory for log message\n");
	return -ENOMEM;
	}

	sprintf(msg, "log %s", log);

	if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM) \|\|
	vmw_send_msg(&channel, msg) \|\|
	vmw_close_channel(&channel)) {
	DRM_ERROR("Failed to send log\n");

	ret = -EINVAL;
	}

	kfree(msg);

	return ret;
	}