linux/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
Roland Scheidegger cb92a32359 drm/vmwgfx: add ioctl for messaging from/to guest userspace to/from host
Up to now, guest userspace does logging directly to host using essentially
the same rather complex port assembly stuff as the kernel.
We'd rather use the same mechanism than duplicate it (it may also change in
the future), hence add a new ioctl for relaying guest/host messaging
(logging is just one application of it).

Signed-off-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
2020-01-15 11:54:16 +01:00

603 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Copyright 2016 VMware, Inc., Palo Alto, CA., USA
*
* 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/frame.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mem_encrypt.h>
#include <asm/hypervisor.h>
#include "vmwgfx_drv.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_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)
#define MAX_USER_MSG_LENGTH PAGE_SIZE
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,
0,
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,
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_port_hb_out - Send the message payload either through the
* high-bandwidth port if available, or through the backdoor otherwise.
* @channel: The rpc channel.
* @msg: NULL-terminated message.
* @hb: Whether the high-bandwidth port is available.
*
* Return: The port status.
*/
static unsigned long vmw_port_hb_out(struct rpc_channel *channel,
const char *msg, bool hb)
{
unsigned long si, di, eax, ebx, ecx, edx;
unsigned long msg_len = strlen(msg);
/* HB port can't access encrypted memory. */
if (hb && !mem_encrypt_active()) {
unsigned long bp = channel->cookie_high;
si = (uintptr_t) msg;
di = channel->cookie_low;
VMW_PORT_HB_OUT(
(MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
msg_len, si, di,
VMWARE_HYPERVISOR_HB | (channel->channel_id << 16) |
VMWARE_HYPERVISOR_OUT,
VMW_HYPERVISOR_MAGIC, bp,
eax, ebx, ecx, edx, si, di);
return ebx;
}
/* HB port not available. Send the message 4 bytes at a time. */
ecx = MESSAGE_STATUS_SUCCESS << 16;
while (msg_len && (HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS)) {
unsigned int bytes = min_t(size_t, msg_len, 4);
unsigned long word = 0;
memcpy(&word, msg, bytes);
msg_len -= bytes;
msg += bytes;
si = channel->cookie_high;
di = channel->cookie_low;
VMW_PORT(VMW_PORT_CMD_MSG | (MSG_TYPE_SENDPAYLOAD << 16),
word, si, di,
channel->channel_id << 16,
VMW_HYPERVISOR_MAGIC,
eax, ebx, ecx, edx, si, di);
}
return ecx;
}
/**
* vmw_port_hb_in - Receive the message payload either through the
* high-bandwidth port if available, or through the backdoor otherwise.
* @channel: The rpc channel.
* @reply: Pointer to buffer holding reply.
* @reply_len: Length of the reply.
* @hb: Whether the high-bandwidth port is available.
*
* Return: The port status.
*/
static unsigned long vmw_port_hb_in(struct rpc_channel *channel, char *reply,
unsigned long reply_len, bool hb)
{
unsigned long si, di, eax, ebx, ecx, edx;
/* HB port can't access encrypted memory */
if (hb && !mem_encrypt_active()) {
unsigned long bp = channel->cookie_low;
si = channel->cookie_high;
di = (uintptr_t) reply;
VMW_PORT_HB_IN(
(MESSAGE_STATUS_SUCCESS << 16) | VMW_PORT_CMD_HB_MSG,
reply_len, si, di,
VMWARE_HYPERVISOR_HB | (channel->channel_id << 16),
VMW_HYPERVISOR_MAGIC, bp,
eax, ebx, ecx, edx, si, di);
return ebx;
}
/* HB port not available. Retrieve the message 4 bytes at a time. */
ecx = MESSAGE_STATUS_SUCCESS << 16;
while (reply_len) {
unsigned int bytes = min_t(unsigned long, reply_len, 4);
si = channel->cookie_high;
di = channel->cookie_low;
VMW_PORT(VMW_PORT_CMD_MSG | (MSG_TYPE_RECVPAYLOAD << 16),
MESSAGE_STATUS_SUCCESS, si, di,
channel->channel_id << 16,
VMW_HYPERVISOR_MAGIC,
eax, ebx, ecx, edx, si, di);
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0)
break;
memcpy(reply, &ebx, bytes);
reply_len -= bytes;
reply += bytes;
}
return ecx;
}
/**
* 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;
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,
channel->channel_id << 16,
VMW_HYPERVISOR_MAGIC,
eax, ebx, ecx, edx, si, di);
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
/* Expected success. Give up. */
return -EINVAL;
}
/* Send msg */
ebx = vmw_port_hb_out(channel, msg,
!!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB));
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;
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,
channel->channel_id << 16,
VMW_HYPERVISOR_MAGIC,
eax, ebx, ecx, edx, si, di);
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
DRM_ERROR("Failed to get reply size for host message.\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) {
DRM_ERROR("Cannot allocate memory for host message reply.\n");
return -ENOMEM;
}
/* Receive buffer */
ebx = vmw_port_hb_in(channel, reply, reply_len,
!!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB));
if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) {
kfree(reply);
reply = NULL;
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,
channel->channel_id << 16,
VMW_HYPERVISOR_MAGIC,
eax, ebx, ecx, edx, si, di);
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
kfree(reply);
reply = NULL;
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_CPT) != 0) {
/* A checkpoint occurred. Retry. */
continue;
}
return -EINVAL;
}
break;
}
if (!reply)
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 reply_len = 0;
if (!vmw_msg_enabled)
return -ENODEV;
if (!guest_info_param || !length)
return -EINVAL;
msg = kasprintf(GFP_KERNEL, "info-get %s", guest_info_param);
if (!msg) {
DRM_ERROR("Cannot allocate memory to get guest info \"%s\".",
guest_info_param);
return -ENOMEM;
}
if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM))
goto out_open;
if (vmw_send_msg(&channel, msg) ||
vmw_recv_msg(&channel, (void *) &reply, &reply_len))
goto out_msg;
vmw_close_channel(&channel);
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 0;
out_msg:
vmw_close_channel(&channel);
kfree(reply);
out_open:
*length = 0;
kfree(msg);
DRM_ERROR("Failed to get guest info \"%s\".", guest_info_param);
return -EINVAL;
}
/**
* 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 ret = 0;
if (!vmw_msg_enabled)
return -ENODEV;
if (!log)
return ret;
msg = kasprintf(GFP_KERNEL, "log %s", log);
if (!msg) {
DRM_ERROR("Cannot allocate memory for host log message.\n");
return -ENOMEM;
}
if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM))
goto out_open;
if (vmw_send_msg(&channel, msg))
goto out_msg;
vmw_close_channel(&channel);
kfree(msg);
return 0;
out_msg:
vmw_close_channel(&channel);
out_open:
kfree(msg);
DRM_ERROR("Failed to send host log message.\n");
return -EINVAL;
}
/**
* vmw_msg_ioctl: Sends and receveives a message to/from host from/to user-space
*
* Sends a message from user-space to host.
* Can also receive a result from host and return that to user-space.
*
* @dev: Identifies the drm device.
* @data: Pointer to the ioctl argument.
* @file_priv: Identifies the caller.
* Return: Zero on success, negative error code on error.
*/
int vmw_msg_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_vmw_msg_arg *arg =
(struct drm_vmw_msg_arg *) data;
struct rpc_channel channel;
char *msg;
int length;
msg = kmalloc(MAX_USER_MSG_LENGTH, GFP_KERNEL);
if (!msg) {
DRM_ERROR("Cannot allocate memory for log message.\n");
return -ENOMEM;
}
length = strncpy_from_user(msg, (void __user *)((unsigned long)arg->send),
MAX_USER_MSG_LENGTH);
if (length < 0 || length >= MAX_USER_MSG_LENGTH) {
DRM_ERROR("Userspace message access failure.\n");
kfree(msg);
return -EINVAL;
}
if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM)) {
DRM_ERROR("Failed to open channel.\n");
goto out_open;
}
if (vmw_send_msg(&channel, msg)) {
DRM_ERROR("Failed to send message to host.\n");
goto out_msg;
}
if (!arg->send_only) {
char *reply = NULL;
size_t reply_len = 0;
if (vmw_recv_msg(&channel, (void *) &reply, &reply_len)) {
DRM_ERROR("Failed to receive message from host.\n");
goto out_msg;
}
if (reply && reply_len > 0) {
if (copy_to_user((void __user *)((unsigned long)arg->receive),
reply, reply_len)) {
DRM_ERROR("Failed to copy message to userspace.\n");
kfree(reply);
goto out_msg;
}
arg->receive_len = (__u32)reply_len;
}
kfree(reply);
}
vmw_close_channel(&channel);
kfree(msg);
return 0;
out_msg:
vmw_close_channel(&channel);
out_open:
kfree(msg);
return -EINVAL;
}