diff options
Diffstat (limited to 'drivers/lguest/lguest_user.c')
-rw-r--r-- | drivers/lguest/lguest_user.c | 446 |
1 files changed, 0 insertions, 446 deletions
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c deleted file mode 100644 index 1a6787bc9386..000000000000 --- a/drivers/lguest/lguest_user.c +++ /dev/null @@ -1,446 +0,0 @@ -/*P:200 This contains all the /dev/lguest code, whereby the userspace - * launcher controls and communicates with the Guest. For example, - * the first write will tell us the Guest's memory layout and entry - * point. A read will run the Guest until something happens, such as - * a signal or the Guest accessing a device. -:*/ -#include <linux/uaccess.h> -#include <linux/miscdevice.h> -#include <linux/fs.h> -#include <linux/sched.h> -#include <linux/sched/mm.h> -#include <linux/file.h> -#include <linux/slab.h> -#include <linux/export.h> -#include "lg.h" - -/*L:052 - The Launcher can get the registers, and also set some of them. -*/ -static int getreg_setup(struct lg_cpu *cpu, const unsigned long __user *input) -{ - unsigned long which; - - /* We re-use the ptrace structure to specify which register to read. */ - if (get_user(which, input) != 0) - return -EFAULT; - - /* - * We set up the cpu register pointer, and their next read will - * actually get the value (instead of running the guest). - * - * The last argument 'true' says we can access any register. - */ - cpu->reg_read = lguest_arch_regptr(cpu, which, true); - if (!cpu->reg_read) - return -ENOENT; - - /* And because this is a write() call, we return the length used. */ - return sizeof(unsigned long) * 2; -} - -static int setreg(struct lg_cpu *cpu, const unsigned long __user *input) -{ - unsigned long which, value, *reg; - - /* We re-use the ptrace structure to specify which register to read. */ - if (get_user(which, input) != 0) - return -EFAULT; - input++; - if (get_user(value, input) != 0) - return -EFAULT; - - /* The last argument 'false' means we can't access all registers. */ - reg = lguest_arch_regptr(cpu, which, false); - if (!reg) - return -ENOENT; - - *reg = value; - - /* And because this is a write() call, we return the length used. */ - return sizeof(unsigned long) * 3; -} - -/*L:050 - * Sending an interrupt is done by writing LHREQ_IRQ and an interrupt - * number to /dev/lguest. - */ -static int user_send_irq(struct lg_cpu *cpu, const unsigned long __user *input) -{ - unsigned long irq; - - if (get_user(irq, input) != 0) - return -EFAULT; - if (irq >= LGUEST_IRQS) - return -EINVAL; - - /* - * Next time the Guest runs, the core code will see if it can deliver - * this interrupt. - */ - set_interrupt(cpu, irq); - return 0; -} - -/*L:053 - * Deliver a trap: this is used by the Launcher if it can't emulate - * an instruction. - */ -static int trap(struct lg_cpu *cpu, const unsigned long __user *input) -{ - unsigned long trapnum; - - if (get_user(trapnum, input) != 0) - return -EFAULT; - - if (!deliver_trap(cpu, trapnum)) - return -EINVAL; - - return 0; -} - -/*L:040 - * Once our Guest is initialized, the Launcher makes it run by reading - * from /dev/lguest. - */ -static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) -{ - struct lguest *lg = file->private_data; - struct lg_cpu *cpu; - unsigned int cpu_id = *o; - - /* You must write LHREQ_INITIALIZE first! */ - if (!lg) - return -EINVAL; - - /* Watch out for arbitrary vcpu indexes! */ - if (cpu_id >= lg->nr_cpus) - return -EINVAL; - - cpu = &lg->cpus[cpu_id]; - - /* If you're not the task which owns the Guest, go away. */ - if (current != cpu->tsk) - return -EPERM; - - /* If the Guest is already dead, we indicate why */ - if (lg->dead) { - size_t len; - - /* lg->dead either contains an error code, or a string. */ - if (IS_ERR(lg->dead)) - return PTR_ERR(lg->dead); - - /* We can only return as much as the buffer they read with. */ - len = min(size, strlen(lg->dead)+1); - if (copy_to_user(user, lg->dead, len) != 0) - return -EFAULT; - return len; - } - - /* - * If we returned from read() last time because the Guest sent I/O, - * clear the flag. - */ - if (cpu->pending.trap) - cpu->pending.trap = 0; - - /* Run the Guest until something interesting happens. */ - return run_guest(cpu, (unsigned long __user *)user); -} - -/*L:025 - * This actually initializes a CPU. For the moment, a Guest is only - * uniprocessor, so "id" is always 0. - */ -static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip) -{ - /* We have a limited number of CPUs in the lguest struct. */ - if (id >= ARRAY_SIZE(cpu->lg->cpus)) - return -EINVAL; - - /* Set up this CPU's id, and pointer back to the lguest struct. */ - cpu->id = id; - cpu->lg = container_of(cpu, struct lguest, cpus[id]); - cpu->lg->nr_cpus++; - - /* Each CPU has a timer it can set. */ - init_clockdev(cpu); - - /* - * We need a complete page for the Guest registers: they are accessible - * to the Guest and we can only grant it access to whole pages. - */ - cpu->regs_page = get_zeroed_page(GFP_KERNEL); - if (!cpu->regs_page) - return -ENOMEM; - - /* We actually put the registers at the end of the page. */ - cpu->regs = (void *)cpu->regs_page + PAGE_SIZE - sizeof(*cpu->regs); - - /* - * Now we initialize the Guest's registers, handing it the start - * address. - */ - lguest_arch_setup_regs(cpu, start_ip); - - /* - * We keep a pointer to the Launcher task (ie. current task) for when - * other Guests want to wake this one (eg. console input). - */ - cpu->tsk = current; - - /* - * We need to keep a pointer to the Launcher's memory map, because if - * the Launcher dies we need to clean it up. If we don't keep a - * reference, it is destroyed before close() is called. - */ - cpu->mm = get_task_mm(cpu->tsk); - - /* - * We remember which CPU's pages this Guest used last, for optimization - * when the same Guest runs on the same CPU twice. - */ - cpu->last_pages = NULL; - - /* No error == success. */ - return 0; -} - -/*L:020 - * The initialization write supplies 3 pointer sized (32 or 64 bit) values (in - * addition to the LHREQ_INITIALIZE value). These are: - * - * base: The start of the Guest-physical memory inside the Launcher memory. - * - * pfnlimit: The highest (Guest-physical) page number the Guest should be - * allowed to access. The Guest memory lives inside the Launcher, so it sets - * this to ensure the Guest can only reach its own memory. - * - * start: The first instruction to execute ("eip" in x86-speak). - */ -static int initialize(struct file *file, const unsigned long __user *input) -{ - /* "struct lguest" contains all we (the Host) know about a Guest. */ - struct lguest *lg; - int err; - unsigned long args[4]; - - /* - * We grab the Big Lguest lock, which protects against multiple - * simultaneous initializations. - */ - mutex_lock(&lguest_lock); - /* You can't initialize twice! Close the device and start again... */ - if (file->private_data) { - err = -EBUSY; - goto unlock; - } - - if (copy_from_user(args, input, sizeof(args)) != 0) { - err = -EFAULT; - goto unlock; - } - - lg = kzalloc(sizeof(*lg), GFP_KERNEL); - if (!lg) { - err = -ENOMEM; - goto unlock; - } - - /* Populate the easy fields of our "struct lguest" */ - lg->mem_base = (void __user *)args[0]; - lg->pfn_limit = args[1]; - lg->device_limit = args[3]; - - /* This is the first cpu (cpu 0) and it will start booting at args[2] */ - err = lg_cpu_start(&lg->cpus[0], 0, args[2]); - if (err) - goto free_lg; - - /* - * Initialize the Guest's shadow page tables. This allocates - * memory, so can fail. - */ - err = init_guest_pagetable(lg); - if (err) - goto free_regs; - - /* We keep our "struct lguest" in the file's private_data. */ - file->private_data = lg; - - mutex_unlock(&lguest_lock); - - /* And because this is a write() call, we return the length used. */ - return sizeof(args); - -free_regs: - /* FIXME: This should be in free_vcpu */ - free_page(lg->cpus[0].regs_page); -free_lg: - kfree(lg); -unlock: - mutex_unlock(&lguest_lock); - return err; -} - -/*L:010 - * The first operation the Launcher does must be a write. All writes - * start with an unsigned long number: for the first write this must be - * LHREQ_INITIALIZE to set up the Guest. After that the Launcher can use - * writes of other values to send interrupts or set up receipt of notifications. - * - * Note that we overload the "offset" in the /dev/lguest file to indicate what - * CPU number we're dealing with. Currently this is always 0 since we only - * support uniprocessor Guests, but you can see the beginnings of SMP support - * here. - */ -static ssize_t write(struct file *file, const char __user *in, - size_t size, loff_t *off) -{ - /* - * Once the Guest is initialized, we hold the "struct lguest" in the - * file private data. - */ - struct lguest *lg = file->private_data; - const unsigned long __user *input = (const unsigned long __user *)in; - unsigned long req; - struct lg_cpu *uninitialized_var(cpu); - unsigned int cpu_id = *off; - - /* The first value tells us what this request is. */ - if (get_user(req, input) != 0) - return -EFAULT; - input++; - - /* If you haven't initialized, you must do that first. */ - if (req != LHREQ_INITIALIZE) { - if (!lg || (cpu_id >= lg->nr_cpus)) - return -EINVAL; - cpu = &lg->cpus[cpu_id]; - - /* Once the Guest is dead, you can only read() why it died. */ - if (lg->dead) - return -ENOENT; - } - - switch (req) { - case LHREQ_INITIALIZE: - return initialize(file, input); - case LHREQ_IRQ: - return user_send_irq(cpu, input); - case LHREQ_GETREG: - return getreg_setup(cpu, input); - case LHREQ_SETREG: - return setreg(cpu, input); - case LHREQ_TRAP: - return trap(cpu, input); - default: - return -EINVAL; - } -} - -static int open(struct inode *inode, struct file *file) -{ - file->private_data = NULL; - - return 0; -} - -/*L:060 - * The final piece of interface code is the close() routine. It reverses - * everything done in initialize(). This is usually called because the - * Launcher exited. - * - * Note that the close routine returns 0 or a negative error number: it can't - * really fail, but it can whine. I blame Sun for this wart, and K&R C for - * letting them do it. -:*/ -static int close(struct inode *inode, struct file *file) -{ - struct lguest *lg = file->private_data; - unsigned int i; - - /* If we never successfully initialized, there's nothing to clean up */ - if (!lg) - return 0; - - /* - * We need the big lock, to protect from inter-guest I/O and other - * Launchers initializing guests. - */ - mutex_lock(&lguest_lock); - - /* Free up the shadow page tables for the Guest. */ - free_guest_pagetable(lg); - - for (i = 0; i < lg->nr_cpus; i++) { - /* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */ - hrtimer_cancel(&lg->cpus[i].hrt); - /* We can free up the register page we allocated. */ - free_page(lg->cpus[i].regs_page); - /* - * Now all the memory cleanups are done, it's safe to release - * the Launcher's memory management structure. - */ - mmput(lg->cpus[i].mm); - } - - /* - * If lg->dead doesn't contain an error code it will be NULL or a - * kmalloc()ed string, either of which is ok to hand to kfree(). - */ - if (!IS_ERR(lg->dead)) - kfree(lg->dead); - /* Free the memory allocated to the lguest_struct */ - kfree(lg); - /* Release lock and exit. */ - mutex_unlock(&lguest_lock); - - return 0; -} - -/*L:000 - * Welcome to our journey through the Launcher! - * - * The Launcher is the Host userspace program which sets up, runs and services - * the Guest. In fact, many comments in the Drivers which refer to "the Host" - * doing things are inaccurate: the Launcher does all the device handling for - * the Guest, but the Guest can't know that. - * - * Just to confuse you: to the Host kernel, the Launcher *is* the Guest and we - * shall see more of that later. - * - * We begin our understanding with the Host kernel interface which the Launcher - * uses: reading and writing a character device called /dev/lguest. All the - * work happens in the read(), write() and close() routines: - */ -static const struct file_operations lguest_fops = { - .owner = THIS_MODULE, - .open = open, - .release = close, - .write = write, - .read = read, - .llseek = default_llseek, -}; -/*:*/ - -/* - * This is a textbook example of a "misc" character device. Populate a "struct - * miscdevice" and register it with misc_register(). - */ -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); -} |