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path: root/drivers/lguest/lguest_user.c
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Diffstat (limited to 'drivers/lguest/lguest_user.c')
-rw-r--r--drivers/lguest/lguest_user.c446
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);
-}