OpenCloudOS-Kernel/drivers/platform/goldfish/goldfish_pipe.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 Intel, Inc.
* Copyright (C) 2013 Intel, Inc.
* Copyright (C) 2014 Linaro Limited
* Copyright (C) 2011-2016 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
/* This source file contains the implementation of a special device driver
* that intends to provide a *very* fast communication channel between the
* guest system and the QEMU emulator.
*
* Usage from the guest is simply the following (error handling simplified):
*
* int fd = open("/dev/qemu_pipe",O_RDWR);
* .... write() or read() through the pipe.
*
* This driver doesn't deal with the exact protocol used during the session.
* It is intended to be as simple as something like:
*
* // do this _just_ after opening the fd to connect to a specific
* // emulator service.
* const char* msg = "<pipename>";
* if (write(fd, msg, strlen(msg)+1) < 0) {
* ... could not connect to <pipename> service
* close(fd);
* }
*
* // after this, simply read() and write() to communicate with the
* // service. Exact protocol details left as an exercise to the reader.
*
* This driver is very fast because it doesn't copy any data through
* intermediate buffers, since the emulator is capable of translating
* guest user addresses into host ones.
*
* Note that we must however ensure that each user page involved in the
* exchange is properly mapped during a transfer.
*/
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/goldfish.h>
#include <linux/dma-mapping.h>
#include <linux/mm.h>
#include <linux/acpi.h>
#include <linux/bug.h>
#include "goldfish_pipe_qemu.h"
/*
* Update this when something changes in the driver's behavior so the host
* can benefit from knowing it
*/
enum {
PIPE_DRIVER_VERSION = 2,
PIPE_CURRENT_DEVICE_VERSION = 2
};
enum {
MAX_BUFFERS_PER_COMMAND = 336,
MAX_SIGNALLED_PIPES = 64,
INITIAL_PIPES_CAPACITY = 64
};
struct goldfish_pipe_dev;
struct goldfish_pipe;
struct goldfish_pipe_command;
/* A per-pipe command structure, shared with the host */
struct goldfish_pipe_command {
s32 cmd; /* PipeCmdCode, guest -> host */
s32 id; /* pipe id, guest -> host */
s32 status; /* command execution status, host -> guest */
s32 reserved; /* to pad to 64-bit boundary */
union {
/* Parameters for PIPE_CMD_{READ,WRITE} */
struct {
/* number of buffers, guest -> host */
u32 buffers_count;
/* number of consumed bytes, host -> guest */
s32 consumed_size;
/* buffer pointers, guest -> host */
u64 ptrs[MAX_BUFFERS_PER_COMMAND];
/* buffer sizes, guest -> host */
u32 sizes[MAX_BUFFERS_PER_COMMAND];
} rw_params;
};
};
/* A single signalled pipe information */
struct signalled_pipe_buffer {
u32 id;
u32 flags;
};
/* Parameters for the PIPE_CMD_OPEN command */
struct open_command_param {
u64 command_buffer_ptr;
u32 rw_params_max_count;
};
/* Device-level set of buffers shared with the host */
struct goldfish_pipe_dev_buffers {
struct open_command_param open_command_params;
struct signalled_pipe_buffer signalled_pipe_buffers[
MAX_SIGNALLED_PIPES];
};
/* This data type models a given pipe instance */
struct goldfish_pipe {
/* pipe ID - index into goldfish_pipe_dev::pipes array */
u32 id;
/* The wake flags pipe is waiting for
* Note: not protected with any lock, uses atomic operations
* and barriers to make it thread-safe.
*/
unsigned long flags;
/* wake flags host have signalled,
* - protected by goldfish_pipe_dev::lock
*/
unsigned long signalled_flags;
/* A pointer to command buffer */
struct goldfish_pipe_command *command_buffer;
/* doubly linked list of signalled pipes, protected by
* goldfish_pipe_dev::lock
*/
struct goldfish_pipe *prev_signalled;
struct goldfish_pipe *next_signalled;
/*
* A pipe's own lock. Protects the following:
* - *command_buffer - makes sure a command can safely write its
* parameters to the host and read the results back.
*/
struct mutex lock;
/* A wake queue for sleeping until host signals an event */
wait_queue_head_t wake_queue;
/* Pointer to the parent goldfish_pipe_dev instance */
struct goldfish_pipe_dev *dev;
};
/* The global driver data. Holds a reference to the i/o page used to
* communicate with the emulator, and a wake queue for blocked tasks
* waiting to be awoken.
*/
struct goldfish_pipe_dev {
/*
* Global device spinlock. Protects the following members:
* - pipes, pipes_capacity
* - [*pipes, *pipes + pipes_capacity) - array data
* - first_signalled_pipe,
* goldfish_pipe::prev_signalled,
* goldfish_pipe::next_signalled,
* goldfish_pipe::signalled_flags - all singnalled-related fields,
* in all allocated pipes
* - open_command_params - PIPE_CMD_OPEN-related buffers
*
* It looks like a lot of different fields, but the trick is that
* the only operation that happens often is the signalled pipes array
* manipulation. That's why it's OK for now to keep the rest of the
* fields under the same lock. If we notice too much contention because
* of PIPE_CMD_OPEN, then we should add a separate lock there.
*/
spinlock_t lock;
/*
* Array of the pipes of |pipes_capacity| elements,
* indexed by goldfish_pipe::id
*/
struct goldfish_pipe **pipes;
u32 pipes_capacity;
/* Pointers to the buffers host uses for interaction with this driver */
struct goldfish_pipe_dev_buffers *buffers;
/* Head of a doubly linked list of signalled pipes */
struct goldfish_pipe *first_signalled_pipe;
/* ptr to platform device's device struct */
struct device *pdev_dev;
/* Some device-specific data */
int irq;
int version;
unsigned char __iomem *base;
};
struct goldfish_pipe_dev goldfish_pipe_dev;
static int goldfish_cmd_locked(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
{
pipe->command_buffer->cmd = cmd;
/* failure by default */
pipe->command_buffer->status = PIPE_ERROR_INVAL;
writel(pipe->id, pipe->dev->base + PIPE_REG_CMD);
return pipe->command_buffer->status;
}
static int goldfish_cmd(struct goldfish_pipe *pipe, enum PipeCmdCode cmd)
{
int status;
if (mutex_lock_interruptible(&pipe->lock))
return PIPE_ERROR_IO;
status = goldfish_cmd_locked(pipe, cmd);
mutex_unlock(&pipe->lock);
return status;
}
/*
* This function converts an error code returned by the emulator through
* the PIPE_REG_STATUS i/o register into a valid negative errno value.
*/
static int goldfish_pipe_error_convert(int status)
{
switch (status) {
case PIPE_ERROR_AGAIN:
return -EAGAIN;
case PIPE_ERROR_NOMEM:
return -ENOMEM;
case PIPE_ERROR_IO:
return -EIO;
default:
return -EINVAL;
}
}
static int pin_user_pages(unsigned long first_page, unsigned long last_page,
unsigned int last_page_size, int is_write,
struct page *pages[MAX_BUFFERS_PER_COMMAND],
unsigned int *iter_last_page_size)
{
int ret;
int requested_pages = ((last_page - first_page) >> PAGE_SHIFT) + 1;
if (requested_pages > MAX_BUFFERS_PER_COMMAND) {
requested_pages = MAX_BUFFERS_PER_COMMAND;
*iter_last_page_size = PAGE_SIZE;
} else {
*iter_last_page_size = last_page_size;
}
ret = get_user_pages_fast(
first_page, requested_pages, !is_write, pages);
if (ret <= 0)
return -EFAULT;
if (ret < requested_pages)
*iter_last_page_size = PAGE_SIZE;
return ret;
}
static void release_user_pages(struct page **pages, int pages_count,
int is_write, s32 consumed_size)
{
int i;
for (i = 0; i < pages_count; i++) {
if (!is_write && consumed_size > 0)
set_page_dirty(pages[i]);
put_page(pages[i]);
}
}
/* Populate the call parameters, merging adjacent pages together */
static void populate_rw_params(
struct page **pages, int pages_count,
unsigned long address, unsigned long address_end,
unsigned long first_page, unsigned long last_page,
unsigned int iter_last_page_size, int is_write,
struct goldfish_pipe_command *command)
{
/*
* Process the first page separately - it's the only page that
* needs special handling for its start address.
*/
unsigned long xaddr = page_to_phys(pages[0]);
unsigned long xaddr_prev = xaddr;
int buffer_idx = 0;
int i = 1;
int size_on_page = first_page == last_page
? (int)(address_end - address)
: (PAGE_SIZE - (address & ~PAGE_MASK));
command->rw_params.ptrs[0] = (u64)(xaddr | (address & ~PAGE_MASK));
command->rw_params.sizes[0] = size_on_page;
for (; i < pages_count; ++i) {
xaddr = page_to_phys(pages[i]);
size_on_page = (i == pages_count - 1) ?
iter_last_page_size : PAGE_SIZE;
if (xaddr == xaddr_prev + PAGE_SIZE) {
command->rw_params.sizes[buffer_idx] += size_on_page;
} else {
++buffer_idx;
command->rw_params.ptrs[buffer_idx] = (u64)xaddr;
command->rw_params.sizes[buffer_idx] = size_on_page;
}
xaddr_prev = xaddr;
}
command->rw_params.buffers_count = buffer_idx + 1;
}
static int transfer_max_buffers(struct goldfish_pipe *pipe,
unsigned long address, unsigned long address_end, int is_write,
unsigned long last_page, unsigned int last_page_size,
s32 *consumed_size, int *status)
{
static struct page *pages[MAX_BUFFERS_PER_COMMAND];
unsigned long first_page = address & PAGE_MASK;
unsigned int iter_last_page_size;
int pages_count = pin_user_pages(first_page, last_page,
last_page_size, is_write,
pages, &iter_last_page_size);
if (pages_count < 0)
return pages_count;
/* Serialize access to the pipe command buffers */
if (mutex_lock_interruptible(&pipe->lock))
return -ERESTARTSYS;
populate_rw_params(pages, pages_count, address, address_end,
first_page, last_page, iter_last_page_size, is_write,
pipe->command_buffer);
/* Transfer the data */
*status = goldfish_cmd_locked(pipe,
is_write ? PIPE_CMD_WRITE : PIPE_CMD_READ);
*consumed_size = pipe->command_buffer->rw_params.consumed_size;
release_user_pages(pages, pages_count, is_write, *consumed_size);
mutex_unlock(&pipe->lock);
return 0;
}
static int wait_for_host_signal(struct goldfish_pipe *pipe, int is_write)
{
u32 wakeBit = is_write ? BIT_WAKE_ON_WRITE : BIT_WAKE_ON_READ;
set_bit(wakeBit, &pipe->flags);
/* Tell the emulator we're going to wait for a wake event */
(void)goldfish_cmd(pipe,
is_write ? PIPE_CMD_WAKE_ON_WRITE : PIPE_CMD_WAKE_ON_READ);
while (test_bit(wakeBit, &pipe->flags)) {
if (wait_event_interruptible(
pipe->wake_queue,
!test_bit(wakeBit, &pipe->flags)))
return -ERESTARTSYS;
if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
return -EIO;
}
return 0;
}
static ssize_t goldfish_pipe_read_write(struct file *filp,
char __user *buffer, size_t bufflen, int is_write)
{
struct goldfish_pipe *pipe = filp->private_data;
int count = 0, ret = -EINVAL;
unsigned long address, address_end, last_page;
unsigned int last_page_size;
/* If the emulator already closed the pipe, no need to go further */
if (unlikely(test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)))
return -EIO;
/* Null reads or writes succeeds */
if (unlikely(bufflen == 0))
return 0;
/* Check the buffer range for access */
if (unlikely(!access_ok(is_write ? VERIFY_WRITE : VERIFY_READ,
buffer, bufflen)))
return -EFAULT;
address = (unsigned long)buffer;
address_end = address + bufflen;
last_page = (address_end - 1) & PAGE_MASK;
last_page_size = ((address_end - 1) & ~PAGE_MASK) + 1;
while (address < address_end) {
s32 consumed_size;
int status;
goldfish_pipe: Pass physical addresses to the device if supported For reading and writing guest user space buffers, currently the kernel sends the guest virtual address of the buffer to the pipe device. This virtual address has to be first converted to a guest physical address. Doing this translation on the QEMU side is inefficient and requires additional handling when KVM is enabled, whose implementation would either incur intrusive changes to QEMU's KVM support code or suffer from poor performance, see commit 08c7228c50f8 ("x86-kvm: only sync SREGS when doing address translation") of $AOSP/external/qemu for details, and thus should be avoided if possible. There is a TODO comment in hw/misc/android_pipe.c in the new Android emulator source tree ($AOSP/external/qemu-android) which requests that the translation be done on the kernel side and that physical addresses be passed to the device instead of virtual ones. Once the QEMU-side implementation is done, the kernel will need to support both the new paddr-based pipe device and the old vaddr-based one (which will continue to be used by the classic emulator). This patch achieves that by leveraging the device version register available in the new device. See https://android-review.googlesource.com/128280 for the QEMU-side patch. In addition, use the mmap semaphore (in read mode) to safeguard the call to get_user_pages(). Signed-off-by: Yu Ning <yu.ning@intel.com> Signed-off-by: Jin Qian <jinqian@android.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-06 22:06:40 +08:00
ret = transfer_max_buffers(pipe, address, address_end, is_write,
last_page, last_page_size, &consumed_size,
&status);
if (ret < 0)
break;
if (consumed_size > 0) {
/* No matter what's the status, we've transferred
* something.
goldfish_pipe: Pass physical addresses to the device if supported For reading and writing guest user space buffers, currently the kernel sends the guest virtual address of the buffer to the pipe device. This virtual address has to be first converted to a guest physical address. Doing this translation on the QEMU side is inefficient and requires additional handling when KVM is enabled, whose implementation would either incur intrusive changes to QEMU's KVM support code or suffer from poor performance, see commit 08c7228c50f8 ("x86-kvm: only sync SREGS when doing address translation") of $AOSP/external/qemu for details, and thus should be avoided if possible. There is a TODO comment in hw/misc/android_pipe.c in the new Android emulator source tree ($AOSP/external/qemu-android) which requests that the translation be done on the kernel side and that physical addresses be passed to the device instead of virtual ones. Once the QEMU-side implementation is done, the kernel will need to support both the new paddr-based pipe device and the old vaddr-based one (which will continue to be used by the classic emulator). This patch achieves that by leveraging the device version register available in the new device. See https://android-review.googlesource.com/128280 for the QEMU-side patch. In addition, use the mmap semaphore (in read mode) to safeguard the call to get_user_pages(). Signed-off-by: Yu Ning <yu.ning@intel.com> Signed-off-by: Jin Qian <jinqian@android.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-06 22:06:40 +08:00
*/
count += consumed_size;
address += consumed_size;
}
if (status > 0)
continue;
if (status == 0) {
/* EOF */
ret = 0;
break;
}
if (count > 0) {
/*
* An error occurred, but we already transferred
* something on one of the previous iterations.
* Just return what we already copied and log this
* err.
*/
if (status != PIPE_ERROR_AGAIN)
dev_err_ratelimited(pipe->dev->pdev_dev,
"backend error %d on %s\n",
status, is_write ? "write" : "read");
break;
}
/*
* If the error is not PIPE_ERROR_AGAIN, or if we are in
* non-blocking mode, just return the error code.
*/
if (status != PIPE_ERROR_AGAIN ||
(filp->f_flags & O_NONBLOCK) != 0) {
ret = goldfish_pipe_error_convert(status);
break;
}
status = wait_for_host_signal(pipe, is_write);
if (status < 0)
return status;
}
if (count > 0)
return count;
return ret;
}
static ssize_t goldfish_pipe_read(struct file *filp, char __user *buffer,
size_t bufflen, loff_t *ppos)
{
return goldfish_pipe_read_write(filp, buffer, bufflen,
/* is_write */ 0);
}
static ssize_t goldfish_pipe_write(struct file *filp,
const char __user *buffer, size_t bufflen,
loff_t *ppos)
{
return goldfish_pipe_read_write(filp,
/* cast away the const */(char __user *)buffer, bufflen,
/* is_write */ 1);
}
static __poll_t goldfish_pipe_poll(struct file *filp, poll_table *wait)
{
struct goldfish_pipe *pipe = filp->private_data;
__poll_t mask = 0;
int status;
poll_wait(filp, &pipe->wake_queue, wait);
status = goldfish_cmd(pipe, PIPE_CMD_POLL);
if (status < 0)
return -ERESTARTSYS;
if (status & PIPE_POLL_IN)
mask |= EPOLLIN | EPOLLRDNORM;
if (status & PIPE_POLL_OUT)
mask |= EPOLLOUT | EPOLLWRNORM;
if (status & PIPE_POLL_HUP)
mask |= EPOLLHUP;
if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
mask |= EPOLLERR;
return mask;
}
static void signalled_pipes_add_locked(struct goldfish_pipe_dev *dev,
u32 id, u32 flags)
{
struct goldfish_pipe *pipe;
if (WARN_ON(id >= dev->pipes_capacity))
return;
pipe = dev->pipes[id];
if (!pipe)
return;
pipe->signalled_flags |= flags;
if (pipe->prev_signalled || pipe->next_signalled
|| dev->first_signalled_pipe == pipe)
return; /* already in the list */
pipe->next_signalled = dev->first_signalled_pipe;
if (dev->first_signalled_pipe)
dev->first_signalled_pipe->prev_signalled = pipe;
dev->first_signalled_pipe = pipe;
}
static void signalled_pipes_remove_locked(struct goldfish_pipe_dev *dev,
struct goldfish_pipe *pipe)
{
if (pipe->prev_signalled)
pipe->prev_signalled->next_signalled = pipe->next_signalled;
if (pipe->next_signalled)
pipe->next_signalled->prev_signalled = pipe->prev_signalled;
if (pipe == dev->first_signalled_pipe)
dev->first_signalled_pipe = pipe->next_signalled;
pipe->prev_signalled = NULL;
pipe->next_signalled = NULL;
}
static struct goldfish_pipe *signalled_pipes_pop_front(
struct goldfish_pipe_dev *dev, int *wakes)
{
struct goldfish_pipe *pipe;
unsigned long flags;
spin_lock_irqsave(&dev->lock, flags);
pipe = dev->first_signalled_pipe;
if (pipe) {
*wakes = pipe->signalled_flags;
pipe->signalled_flags = 0;
/*
* This is an optimized version of
* signalled_pipes_remove_locked()
* - We want to make it as fast as possible to
* wake the sleeping pipe operations faster.
*/
dev->first_signalled_pipe = pipe->next_signalled;
if (dev->first_signalled_pipe)
dev->first_signalled_pipe->prev_signalled = NULL;
pipe->next_signalled = NULL;
}
spin_unlock_irqrestore(&dev->lock, flags);
return pipe;
}
static void goldfish_interrupt_task(unsigned long unused)
{
/* Iterate over the signalled pipes and wake them one by one */
struct goldfish_pipe *pipe;
int wakes;
while ((pipe = signalled_pipes_pop_front(&goldfish_pipe_dev, &wakes)) !=
NULL) {
if (wakes & PIPE_WAKE_CLOSED) {
pipe->flags = 1 << BIT_CLOSED_ON_HOST;
} else {
if (wakes & PIPE_WAKE_READ)
clear_bit(BIT_WAKE_ON_READ, &pipe->flags);
if (wakes & PIPE_WAKE_WRITE)
clear_bit(BIT_WAKE_ON_WRITE, &pipe->flags);
}
/*
* wake_up_interruptible() implies a write barrier, so don't
* explicitly add another one here.
*/
wake_up_interruptible(&pipe->wake_queue);
}
}
static DECLARE_TASKLET(goldfish_interrupt_tasklet, goldfish_interrupt_task, 0);
/*
* The general idea of the interrupt handling:
*
* 1. device raises an interrupt if there's at least one signalled pipe
* 2. IRQ handler reads the signalled pipes and their count from the device
* 3. device writes them into a shared buffer and returns the count
* it only resets the IRQ if it has returned all signalled pipes,
* otherwise it leaves it raised, so IRQ handler will be called
* again for the next chunk
* 4. IRQ handler adds all returned pipes to the device's signalled pipes list
* 5. IRQ handler launches a tasklet to process the signalled pipes from the
* list in a separate context
*/
static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)
{
u32 count;
u32 i;
unsigned long flags;
struct goldfish_pipe_dev *dev = dev_id;
if (dev != &goldfish_pipe_dev)
return IRQ_NONE;
/* Request the signalled pipes from the device */
spin_lock_irqsave(&dev->lock, flags);
count = readl(dev->base + PIPE_REG_GET_SIGNALLED);
if (count == 0) {
spin_unlock_irqrestore(&dev->lock, flags);
return IRQ_NONE;
}
if (count > MAX_SIGNALLED_PIPES)
count = MAX_SIGNALLED_PIPES;
for (i = 0; i < count; ++i)
signalled_pipes_add_locked(dev,
dev->buffers->signalled_pipe_buffers[i].id,
dev->buffers->signalled_pipe_buffers[i].flags);
spin_unlock_irqrestore(&dev->lock, flags);
tasklet_schedule(&goldfish_interrupt_tasklet);
return IRQ_HANDLED;
}
static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev)
{
int id;
for (id = 0; id < dev->pipes_capacity; ++id)
if (!dev->pipes[id])
return id;
{
/* Reallocate the array.
* Since get_free_pipe_id_locked runs with interrupts disabled,
* we don't want to make calls that could lead to sleep.
*/
u32 new_capacity = 2 * dev->pipes_capacity;
struct goldfish_pipe **pipes =
kcalloc(new_capacity, sizeof(*pipes), GFP_ATOMIC);
if (!pipes)
return -ENOMEM;
memcpy(pipes, dev->pipes, sizeof(*pipes) * dev->pipes_capacity);
kfree(dev->pipes);
dev->pipes = pipes;
id = dev->pipes_capacity;
dev->pipes_capacity = new_capacity;
}
return id;
}
/**
* goldfish_pipe_open - open a channel to the AVD
* @inode: inode of device
* @file: file struct of opener
*
* Create a new pipe link between the emulator and the use application.
* Each new request produces a new pipe.
*
* Note: we use the pipe ID as a mux. All goldfish emulations are 32bit
* right now so this is fine. A move to 64bit will need this addressing
*/
static int goldfish_pipe_open(struct inode *inode, struct file *file)
{
struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
unsigned long flags;
int id;
int status;
/* Allocate new pipe kernel object */
struct goldfish_pipe *pipe = kzalloc(sizeof(*pipe), GFP_KERNEL);
if (pipe == NULL)
return -ENOMEM;
pipe->dev = dev;
mutex_init(&pipe->lock);
init_waitqueue_head(&pipe->wake_queue);
/*
* Command buffer needs to be allocated on its own page to make sure
* it is physically contiguous in host's address space.
*/
BUILD_BUG_ON(sizeof(struct goldfish_pipe_command) > PAGE_SIZE);
pipe->command_buffer =
(struct goldfish_pipe_command *)__get_free_page(GFP_KERNEL);
if (!pipe->command_buffer) {
status = -ENOMEM;
goto err_pipe;
}
spin_lock_irqsave(&dev->lock, flags);
id = get_free_pipe_id_locked(dev);
if (id < 0) {
status = id;
goto err_id_locked;
}
dev->pipes[id] = pipe;
pipe->id = id;
pipe->command_buffer->id = id;
/* Now tell the emulator we're opening a new pipe. */
dev->buffers->open_command_params.rw_params_max_count =
MAX_BUFFERS_PER_COMMAND;
dev->buffers->open_command_params.command_buffer_ptr =
(u64)(unsigned long)__pa(pipe->command_buffer);
status = goldfish_cmd_locked(pipe, PIPE_CMD_OPEN);
spin_unlock_irqrestore(&dev->lock, flags);
if (status < 0)
goto err_cmd;
/* All is done, save the pipe into the file's private data field */
file->private_data = pipe;
return 0;
err_cmd:
spin_lock_irqsave(&dev->lock, flags);
dev->pipes[id] = NULL;
err_id_locked:
spin_unlock_irqrestore(&dev->lock, flags);
free_page((unsigned long)pipe->command_buffer);
err_pipe:
kfree(pipe);
return status;
}
static int goldfish_pipe_release(struct inode *inode, struct file *filp)
{
unsigned long flags;
struct goldfish_pipe *pipe = filp->private_data;
struct goldfish_pipe_dev *dev = pipe->dev;
/* The guest is closing the channel, so tell the emulator right now */
(void)goldfish_cmd(pipe, PIPE_CMD_CLOSE);
spin_lock_irqsave(&dev->lock, flags);
dev->pipes[pipe->id] = NULL;
signalled_pipes_remove_locked(dev, pipe);
spin_unlock_irqrestore(&dev->lock, flags);
filp->private_data = NULL;
free_page((unsigned long)pipe->command_buffer);
kfree(pipe);
return 0;
}
static const struct file_operations goldfish_pipe_fops = {
.owner = THIS_MODULE,
.read = goldfish_pipe_read,
.write = goldfish_pipe_write,
.poll = goldfish_pipe_poll,
.open = goldfish_pipe_open,
.release = goldfish_pipe_release,
};
static struct miscdevice goldfish_pipe_miscdev = {
.minor = MISC_DYNAMIC_MINOR,
.name = "goldfish_pipe",
.fops = &goldfish_pipe_fops,
};
static int goldfish_pipe_device_init(struct platform_device *pdev)
{
struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
int err = devm_request_irq(&pdev->dev, dev->irq,
goldfish_pipe_interrupt,
IRQF_SHARED, "goldfish_pipe", dev);
if (err) {
dev_err(&pdev->dev, "unable to allocate IRQ for v2\n");
return err;
}
err = misc_register(&goldfish_pipe_miscdev);
if (err) {
dev_err(&pdev->dev, "unable to register v2 device\n");
return err;
}
dev->pdev_dev = &pdev->dev;
dev->first_signalled_pipe = NULL;
dev->pipes_capacity = INITIAL_PIPES_CAPACITY;
dev->pipes = kcalloc(dev->pipes_capacity, sizeof(*dev->pipes),
GFP_KERNEL);
if (!dev->pipes)
return -ENOMEM;
/*
* We're going to pass two buffers, open_command_params and
* signalled_pipe_buffers, to the host. This means each of those buffers
* needs to be contained in a single physical page. The easiest choice
* is to just allocate a page and place the buffers in it.
*/
BUILD_BUG_ON(sizeof(struct goldfish_pipe_dev_buffers) > PAGE_SIZE);
dev->buffers = (struct goldfish_pipe_dev_buffers *)
__get_free_page(GFP_KERNEL);
if (!dev->buffers) {
kfree(dev->pipes);
return -ENOMEM;
}
/* Send the buffer addresses to the host */
{
u64 paddr = __pa(&dev->buffers->signalled_pipe_buffers);
writel((u32)(unsigned long)(paddr >> 32),
dev->base + PIPE_REG_SIGNAL_BUFFER_HIGH);
writel((u32)(unsigned long)paddr,
dev->base + PIPE_REG_SIGNAL_BUFFER);
writel((u32)MAX_SIGNALLED_PIPES,
dev->base + PIPE_REG_SIGNAL_BUFFER_COUNT);
paddr = __pa(&dev->buffers->open_command_params);
writel((u32)(unsigned long)(paddr >> 32),
dev->base + PIPE_REG_OPEN_BUFFER_HIGH);
writel((u32)(unsigned long)paddr,
dev->base + PIPE_REG_OPEN_BUFFER);
}
return 0;
}
static void goldfish_pipe_device_deinit(struct platform_device *pdev)
{
misc_deregister(&goldfish_pipe_miscdev);
kfree(goldfish_pipe_dev.pipes);
free_page((unsigned long)goldfish_pipe_dev.buffers);
}
static int goldfish_pipe_probe(struct platform_device *pdev)
{
int err;
struct resource *r;
struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
/* not thread safe, but this should not happen */
WARN_ON(dev->base != NULL);
spin_lock_init(&dev->lock);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (r == NULL || resource_size(r) < PAGE_SIZE) {
dev_err(&pdev->dev, "can't allocate i/o page\n");
return -EINVAL;
}
dev->base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
if (dev->base == NULL) {
dev_err(&pdev->dev, "ioremap failed\n");
return -EINVAL;
}
r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (r == NULL) {
err = -EINVAL;
goto error;
}
dev->irq = r->start;
/*
* Exchange the versions with the host device
*
* Note: v1 driver used to not report its version, so we write it before
* reading device version back: this allows the host implementation to
* detect the old driver (if there was no version write before read).
goldfish_pipe: Pass physical addresses to the device if supported For reading and writing guest user space buffers, currently the kernel sends the guest virtual address of the buffer to the pipe device. This virtual address has to be first converted to a guest physical address. Doing this translation on the QEMU side is inefficient and requires additional handling when KVM is enabled, whose implementation would either incur intrusive changes to QEMU's KVM support code or suffer from poor performance, see commit 08c7228c50f8 ("x86-kvm: only sync SREGS when doing address translation") of $AOSP/external/qemu for details, and thus should be avoided if possible. There is a TODO comment in hw/misc/android_pipe.c in the new Android emulator source tree ($AOSP/external/qemu-android) which requests that the translation be done on the kernel side and that physical addresses be passed to the device instead of virtual ones. Once the QEMU-side implementation is done, the kernel will need to support both the new paddr-based pipe device and the old vaddr-based one (which will continue to be used by the classic emulator). This patch achieves that by leveraging the device version register available in the new device. See https://android-review.googlesource.com/128280 for the QEMU-side patch. In addition, use the mmap semaphore (in read mode) to safeguard the call to get_user_pages(). Signed-off-by: Yu Ning <yu.ning@intel.com> Signed-off-by: Jin Qian <jinqian@android.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-06 22:06:40 +08:00
*/
writel((u32)PIPE_DRIVER_VERSION, dev->base + PIPE_REG_VERSION);
goldfish_pipe: Pass physical addresses to the device if supported For reading and writing guest user space buffers, currently the kernel sends the guest virtual address of the buffer to the pipe device. This virtual address has to be first converted to a guest physical address. Doing this translation on the QEMU side is inefficient and requires additional handling when KVM is enabled, whose implementation would either incur intrusive changes to QEMU's KVM support code or suffer from poor performance, see commit 08c7228c50f8 ("x86-kvm: only sync SREGS when doing address translation") of $AOSP/external/qemu for details, and thus should be avoided if possible. There is a TODO comment in hw/misc/android_pipe.c in the new Android emulator source tree ($AOSP/external/qemu-android) which requests that the translation be done on the kernel side and that physical addresses be passed to the device instead of virtual ones. Once the QEMU-side implementation is done, the kernel will need to support both the new paddr-based pipe device and the old vaddr-based one (which will continue to be used by the classic emulator). This patch achieves that by leveraging the device version register available in the new device. See https://android-review.googlesource.com/128280 for the QEMU-side patch. In addition, use the mmap semaphore (in read mode) to safeguard the call to get_user_pages(). Signed-off-by: Yu Ning <yu.ning@intel.com> Signed-off-by: Jin Qian <jinqian@android.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-06 22:06:40 +08:00
dev->version = readl(dev->base + PIPE_REG_VERSION);
if (WARN_ON(dev->version < PIPE_CURRENT_DEVICE_VERSION))
return -EINVAL;
err = goldfish_pipe_device_init(pdev);
if (!err)
return 0;
error:
dev->base = NULL;
return err;
}
static int goldfish_pipe_remove(struct platform_device *pdev)
{
struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
goldfish_pipe_device_deinit(pdev);
dev->base = NULL;
return 0;
}
static const struct acpi_device_id goldfish_pipe_acpi_match[] = {
{ "GFSH0003", 0 },
{ },
};
MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match);
static const struct of_device_id goldfish_pipe_of_match[] = {
{ .compatible = "google,android-pipe", },
{},
};
MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match);
static struct platform_driver goldfish_pipe_driver = {
.probe = goldfish_pipe_probe,
.remove = goldfish_pipe_remove,
.driver = {
.name = "goldfish_pipe",
.of_match_table = goldfish_pipe_of_match,
.acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match),
}
};
module_platform_driver(goldfish_pipe_driver);
MODULE_AUTHOR("David Turner <digit@google.com>");
MODULE_LICENSE("GPL v2");