diff options
Diffstat (limited to 'drivers/lguest/lguest_user.c')
| -rw-r--r-- | drivers/lguest/lguest_user.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c new file mode 100644 index 00000000000..e90d7a783da --- /dev/null +++ b/drivers/lguest/lguest_user.c @@ -0,0 +1,236 @@ +/* Userspace control of the guest, via /dev/lguest. */ +#include <linux/uaccess.h> +#include <linux/miscdevice.h> +#include <linux/fs.h> +#include "lg.h" + +static void setup_regs(struct lguest_regs *regs, unsigned long start) +{ + /* Write out stack in format lguest expects, so we can switch to it. */ + regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL; + regs->cs = __KERNEL_CS|GUEST_PL; + regs->eflags = 0x202; /* Interrupts enabled. */ + regs->eip = start; + /* esi points to our boot information (physical address 0) */ +} + +/* + addr */ +static long user_get_dma(struct lguest *lg, const u32 __user *input) +{ + unsigned long key, udma, irq; + + if (get_user(key, input) != 0) + return -EFAULT; + udma = get_dma_buffer(lg, key, &irq); + if (!udma) + return -ENOENT; + + /* We put irq number in udma->used_len. */ + lgwrite_u32(lg, udma + offsetof(struct lguest_dma, used_len), irq); + return udma; +} + +/* To force the Guest to stop running and return to the Launcher, the + * Waker sets writes LHREQ_BREAK and the value "1" to /dev/lguest. The + * Launcher then writes LHREQ_BREAK and "0" to release the Waker. */ +static int break_guest_out(struct lguest *lg, const u32 __user *input) +{ + unsigned long on; + + /* Fetch whether they're turning break on or off.. */ + if (get_user(on, input) != 0) + return -EFAULT; + + if (on) { + lg->break_out = 1; + /* Pop it out (may be running on different CPU) */ + wake_up_process(lg->tsk); + /* Wait for them to reset it */ + return wait_event_interruptible(lg->break_wq, !lg->break_out); + } else { + lg->break_out = 0; + wake_up(&lg->break_wq); + return 0; + } +} + +/* + irq */ +static int user_send_irq(struct lguest *lg, const u32 __user *input) +{ + u32 irq; + + if (get_user(irq, input) != 0) + return -EFAULT; + if (irq >= LGUEST_IRQS) + return -EINVAL; + set_bit(irq, lg->irqs_pending); + return 0; +} + +static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) +{ + struct lguest *lg = file->private_data; + + if (!lg) + return -EINVAL; + + /* If you're not the task which owns the guest, go away. */ + if (current != lg->tsk) + return -EPERM; + + if (lg->dead) { + size_t len; + + if (IS_ERR(lg->dead)) + return PTR_ERR(lg->dead); + + len = min(size, strlen(lg->dead)+1); + if (copy_to_user(user, lg->dead, len) != 0) + return -EFAULT; + return len; + } + + if (lg->dma_is_pending) + lg->dma_is_pending = 0; + + return run_guest(lg, (unsigned long __user *)user); +} + +/* Take: pfnlimit, pgdir, start, pageoffset. */ +static int initialize(struct file *file, const u32 __user *input) +{ + struct lguest *lg; + int err, i; + u32 args[4]; + + /* We grab the Big Lguest lock, which protects the global array + * "lguests" and multiple simultaneous initializations. */ + mutex_lock(&lguest_lock); + + if (file->private_data) { + err = -EBUSY; + goto unlock; + } + + if (copy_from_user(args, input, sizeof(args)) != 0) { + err = -EFAULT; + goto unlock; + } + + i = find_free_guest(); + if (i < 0) { + err = -ENOSPC; + goto unlock; + } + lg = &lguests[i]; + lg->guestid = i; + lg->pfn_limit = args[0]; + lg->page_offset = args[3]; + lg->regs_page = get_zeroed_page(GFP_KERNEL); + if (!lg->regs_page) { + err = -ENOMEM; + goto release_guest; + } + lg->regs = (void *)lg->regs_page + PAGE_SIZE - sizeof(*lg->regs); + + err = init_guest_pagetable(lg, args[1]); + if (err) + goto free_regs; + + setup_regs(lg->regs, args[2]); + setup_guest_gdt(lg); + init_clockdev(lg); + lg->tsk = current; + lg->mm = get_task_mm(lg->tsk); + init_waitqueue_head(&lg->break_wq); + lg->last_pages = NULL; + file->private_data = lg; + + mutex_unlock(&lguest_lock); + + return sizeof(args); + +free_regs: + free_page(lg->regs_page); +release_guest: + memset(lg, 0, sizeof(*lg)); +unlock: + mutex_unlock(&lguest_lock); + return err; +} + +static ssize_t write(struct file *file, const char __user *input, + size_t size, loff_t *off) +{ + struct lguest *lg = file->private_data; + u32 req; + + if (get_user(req, input) != 0) + return -EFAULT; + input += sizeof(req); + + if (req != LHREQ_INITIALIZE && !lg) + return -EINVAL; + if (lg && lg->dead) + return -ENOENT; + + /* If you're not the task which owns the Guest, you can only break */ + if (lg && current != lg->tsk && req != LHREQ_BREAK) + return -EPERM; + + switch (req) { + case LHREQ_INITIALIZE: + return initialize(file, (const u32 __user *)input); + case LHREQ_GETDMA: + return user_get_dma(lg, (const u32 __user *)input); + case LHREQ_IRQ: + return user_send_irq(lg, (const u32 __user *)input); + case LHREQ_BREAK: + return break_guest_out(lg, (const u32 __user *)input); + default: + return -EINVAL; + } +} + +static int close(struct inode *inode, struct file *file) +{ + struct lguest *lg = file->private_data; + + if (!lg) + return 0; + + mutex_lock(&lguest_lock); + /* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */ + hrtimer_cancel(&lg->hrt); + release_all_dma(lg); + free_guest_pagetable(lg); + mmput(lg->mm); + if (!IS_ERR(lg->dead)) + kfree(lg->dead); + free_page(lg->regs_page); + memset(lg, 0, sizeof(*lg)); + mutex_unlock(&lguest_lock); + return 0; +} + +static struct file_operations lguest_fops = { + .owner = THIS_MODULE, + .release = close, + .write = write, + .read = read, +}; +static struct miscdevice lguest_dev = { + .minor = MISC_DYNAMIC_MINOR, + .name = "lguest", + .fops = &lguest_fops, +}; + +int __init lguest_device_init(void) +{ + return misc_register(&lguest_dev); +} + +void __exit lguest_device_remove(void) +{ + misc_deregister(&lguest_dev); +} |