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Diffstat (limited to 'drivers/lguest/core.c')
-rw-r--r--drivers/lguest/core.c398
1 files changed, 0 insertions, 398 deletions
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
deleted file mode 100644
index 395ed1961dbf..000000000000
--- a/drivers/lguest/core.c
+++ /dev/null
@@ -1,398 +0,0 @@
-/*P:400
- * This contains run_guest() which actually calls into the Host<->Guest
- * Switcher and analyzes the return, such as determining if the Guest wants the
- * Host to do something. This file also contains useful helper routines.
-:*/
-#include <linux/module.h>
-#include <linux/stringify.h>
-#include <linux/stddef.h>
-#include <linux/io.h>
-#include <linux/mm.h>
-#include <linux/sched/signal.h>
-#include <linux/vmalloc.h>
-#include <linux/cpu.h>
-#include <linux/freezer.h>
-#include <linux/highmem.h>
-#include <linux/slab.h>
-#include <asm/paravirt.h>
-#include <asm/pgtable.h>
-#include <linux/uaccess.h>
-#include <asm/poll.h>
-#include <asm/asm-offsets.h>
-#include "lg.h"
-
-unsigned long switcher_addr;
-struct page **lg_switcher_pages;
-static struct vm_struct *switcher_text_vma;
-static struct vm_struct *switcher_stacks_vma;
-
-/* This One Big lock protects all inter-guest data structures. */
-DEFINE_MUTEX(lguest_lock);
-
-/*H:010
- * We need to set up the Switcher at a high virtual address. Remember the
- * Switcher is a few hundred bytes of assembler code which actually changes the
- * CPU to run the Guest, and then changes back to the Host when a trap or
- * interrupt happens.
- *
- * The Switcher code must be at the same virtual address in the Guest as the
- * Host since it will be running as the switchover occurs.
- *
- * Trying to map memory at a particular address is an unusual thing to do, so
- * it's not a simple one-liner.
- */
-static __init int map_switcher(void)
-{
- int i, err;
-
- /*
- * Map the Switcher in to high memory.
- *
- * It turns out that if we choose the address 0xFFC00000 (4MB under the
- * top virtual address), it makes setting up the page tables really
- * easy.
- */
-
- /* We assume Switcher text fits into a single page. */
- if (end_switcher_text - start_switcher_text > PAGE_SIZE) {
- printk(KERN_ERR "lguest: switcher text too large (%zu)\n",
- end_switcher_text - start_switcher_text);
- return -EINVAL;
- }
-
- /*
- * We allocate an array of struct page pointers. map_vm_area() wants
- * this, rather than just an array of pages.
- */
- lg_switcher_pages = kmalloc(sizeof(lg_switcher_pages[0])
- * TOTAL_SWITCHER_PAGES,
- GFP_KERNEL);
- if (!lg_switcher_pages) {
- err = -ENOMEM;
- goto out;
- }
-
- /*
- * Now we actually allocate the pages. The Guest will see these pages,
- * so we make sure they're zeroed.
- */
- for (i = 0; i < TOTAL_SWITCHER_PAGES; i++) {
- lg_switcher_pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
- if (!lg_switcher_pages[i]) {
- err = -ENOMEM;
- goto free_some_pages;
- }
- }
-
- /*
- * Copy in the compiled-in Switcher code (from x86/switcher_32.S).
- * It goes in the first page, which we map in momentarily.
- */
- memcpy(kmap(lg_switcher_pages[0]), start_switcher_text,
- end_switcher_text - start_switcher_text);
- kunmap(lg_switcher_pages[0]);
-
- /*
- * We place the Switcher underneath the fixmap area, which is the
- * highest virtual address we can get. This is important, since we
- * tell the Guest it can't access this memory, so we want its ceiling
- * as high as possible.
- */
- switcher_addr = FIXADDR_START - TOTAL_SWITCHER_PAGES*PAGE_SIZE;
-
- /*
- * Now we reserve the "virtual memory area"s we want. We might
- * not get them in theory, but in practice it's worked so far.
- *
- * We want the switcher text to be read-only and executable, and
- * the stacks to be read-write and non-executable.
- */
- switcher_text_vma = __get_vm_area(PAGE_SIZE, VM_ALLOC|VM_NO_GUARD,
- switcher_addr,
- switcher_addr + PAGE_SIZE);
-
- if (!switcher_text_vma) {
- err = -ENOMEM;
- printk("lguest: could not map switcher pages high\n");
- goto free_pages;
- }
-
- switcher_stacks_vma = __get_vm_area(SWITCHER_STACK_PAGES * PAGE_SIZE,
- VM_ALLOC|VM_NO_GUARD,
- switcher_addr + PAGE_SIZE,
- switcher_addr + TOTAL_SWITCHER_PAGES * PAGE_SIZE);
- if (!switcher_stacks_vma) {
- err = -ENOMEM;
- printk("lguest: could not map switcher pages high\n");
- goto free_text_vma;
- }
-
- /*
- * This code actually sets up the pages we've allocated to appear at
- * switcher_addr. map_vm_area() takes the vma we allocated above, the
- * kind of pages we're mapping (kernel text pages and kernel writable
- * pages respectively), and a pointer to our array of struct pages.
- */
- err = map_vm_area(switcher_text_vma, PAGE_KERNEL_RX, lg_switcher_pages);
- if (err) {
- printk("lguest: text map_vm_area failed: %i\n", err);
- goto free_vmas;
- }
-
- err = map_vm_area(switcher_stacks_vma, PAGE_KERNEL,
- lg_switcher_pages + SWITCHER_TEXT_PAGES);
- if (err) {
- printk("lguest: stacks map_vm_area failed: %i\n", err);
- goto free_vmas;
- }
-
- /*
- * Now the Switcher is mapped at the right address, we can't fail!
- */
- printk(KERN_INFO "lguest: mapped switcher at %p\n",
- switcher_text_vma->addr);
- /* And we succeeded... */
- return 0;
-
-free_vmas:
- /* Undoes map_vm_area and __get_vm_area */
- vunmap(switcher_stacks_vma->addr);
-free_text_vma:
- vunmap(switcher_text_vma->addr);
-free_pages:
- i = TOTAL_SWITCHER_PAGES;
-free_some_pages:
- for (--i; i >= 0; i--)
- __free_pages(lg_switcher_pages[i], 0);
- kfree(lg_switcher_pages);
-out:
- return err;
-}
-/*:*/
-
-/* Cleaning up the mapping when the module is unloaded is almost... too easy. */
-static void unmap_switcher(void)
-{
- unsigned int i;
-
- /* vunmap() undoes *both* map_vm_area() and __get_vm_area(). */
- vunmap(switcher_text_vma->addr);
- vunmap(switcher_stacks_vma->addr);
- /* Now we just need to free the pages we copied the switcher into */
- for (i = 0; i < TOTAL_SWITCHER_PAGES; i++)
- __free_pages(lg_switcher_pages[i], 0);
- kfree(lg_switcher_pages);
-}
-
-/*H:032
- * Dealing With Guest Memory.
- *
- * Before we go too much further into the Host, we need to grok the routines
- * we use to deal with Guest memory.
- *
- * When the Guest gives us (what it thinks is) a physical address, we can use
- * the normal copy_from_user() & copy_to_user() on the corresponding place in
- * the memory region allocated by the Launcher.
- *
- * But we can't trust the Guest: it might be trying to access the Launcher
- * code. We have to check that the range is below the pfn_limit the Launcher
- * gave us. We have to make sure that addr + len doesn't give us a false
- * positive by overflowing, too.
- */
-bool lguest_address_ok(const struct lguest *lg,
- unsigned long addr, unsigned long len)
-{
- return addr+len <= lg->pfn_limit * PAGE_SIZE && (addr+len >= addr);
-}
-
-/*
- * This routine copies memory from the Guest. Here we can see how useful the
- * kill_lguest() routine we met in the Launcher can be: we return a random
- * value (all zeroes) instead of needing to return an error.
- */
-void __lgread(struct lg_cpu *cpu, void *b, unsigned long addr, unsigned bytes)
-{
- if (!lguest_address_ok(cpu->lg, addr, bytes)
- || copy_from_user(b, cpu->lg->mem_base + addr, bytes) != 0) {
- /* copy_from_user should do this, but as we rely on it... */
- memset(b, 0, bytes);
- kill_guest(cpu, "bad read address %#lx len %u", addr, bytes);
- }
-}
-
-/* This is the write (copy into Guest) version. */
-void __lgwrite(struct lg_cpu *cpu, unsigned long addr, const void *b,
- unsigned bytes)
-{
- if (!lguest_address_ok(cpu->lg, addr, bytes)
- || copy_to_user(cpu->lg->mem_base + addr, b, bytes) != 0)
- kill_guest(cpu, "bad write address %#lx len %u", addr, bytes);
-}
-/*:*/
-
-/*H:030
- * Let's jump straight to the the main loop which runs the Guest.
- * Remember, this is called by the Launcher reading /dev/lguest, and we keep
- * going around and around until something interesting happens.
- */
-int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
-{
- /* If the launcher asked for a register with LHREQ_GETREG */
- if (cpu->reg_read) {
- if (put_user(*cpu->reg_read, user))
- return -EFAULT;
- cpu->reg_read = NULL;
- return sizeof(*cpu->reg_read);
- }
-
- /* We stop running once the Guest is dead. */
- while (!cpu->lg->dead) {
- unsigned int irq;
- bool more;
-
- /* First we run any hypercalls the Guest wants done. */
- if (cpu->hcall)
- do_hypercalls(cpu);
-
- /* Do we have to tell the Launcher about a trap? */
- if (cpu->pending.trap) {
- if (copy_to_user(user, &cpu->pending,
- sizeof(cpu->pending)))
- return -EFAULT;
- return sizeof(cpu->pending);
- }
-
- /*
- * All long-lived kernel loops need to check with this horrible
- * thing called the freezer. If the Host is trying to suspend,
- * it stops us.
- */
- try_to_freeze();
-
- /* Check for signals */
- if (signal_pending(current))
- return -ERESTARTSYS;
-
- /*
- * Check if there are any interrupts which can be delivered now:
- * if so, this sets up the hander to be executed when we next
- * run the Guest.
- */
- irq = interrupt_pending(cpu, &more);
- if (irq < LGUEST_IRQS)
- try_deliver_interrupt(cpu, irq, more);
-
- /*
- * Just make absolutely sure the Guest is still alive. One of
- * those hypercalls could have been fatal, for example.
- */
- if (cpu->lg->dead)
- break;
-
- /*
- * If the Guest asked to be stopped, we sleep. The Guest's
- * clock timer will wake us.
- */
- if (cpu->halted) {
- set_current_state(TASK_INTERRUPTIBLE);
- /*
- * Just before we sleep, make sure no interrupt snuck in
- * which we should be doing.
- */
- if (interrupt_pending(cpu, &more) < LGUEST_IRQS)
- set_current_state(TASK_RUNNING);
- else
- schedule();
- continue;
- }
-
- /*
- * OK, now we're ready to jump into the Guest. First we put up
- * the "Do Not Disturb" sign:
- */
- local_irq_disable();
-
- /* Actually run the Guest until something happens. */
- lguest_arch_run_guest(cpu);
-
- /* Now we're ready to be interrupted or moved to other CPUs */
- local_irq_enable();
-
- /* Now we deal with whatever happened to the Guest. */
- lguest_arch_handle_trap(cpu);
- }
-
- /* Special case: Guest is 'dead' but wants a reboot. */
- if (cpu->lg->dead == ERR_PTR(-ERESTART))
- return -ERESTART;
-
- /* The Guest is dead => "No such file or directory" */
- return -ENOENT;
-}
-
-/*H:000
- * Welcome to the Host!
- *
- * By this point your brain has been tickled by the Guest code and numbed by
- * the Launcher code; prepare for it to be stretched by the Host code. This is
- * the heart. Let's begin at the initialization routine for the Host's lg
- * module.
- */
-static int __init init(void)
-{
- int err;
-
- /* Lguest can't run under Xen, VMI or itself. It does Tricky Stuff. */
- if (get_kernel_rpl() != 0) {
- printk("lguest is afraid of being a guest\n");
- return -EPERM;
- }
-
- /* First we put the Switcher up in very high virtual memory. */
- err = map_switcher();
- if (err)
- goto out;
-
- /* We might need to reserve an interrupt vector. */
- err = init_interrupts();
- if (err)
- goto unmap;
-
- /* /dev/lguest needs to be registered. */
- err = lguest_device_init();
- if (err)
- goto free_interrupts;
-
- /* Finally we do some architecture-specific setup. */
- lguest_arch_host_init();
-
- /* All good! */
- return 0;
-
-free_interrupts:
- free_interrupts();
-unmap:
- unmap_switcher();
-out:
- return err;
-}
-
-/* Cleaning up is just the same code, backwards. With a little French. */
-static void __exit fini(void)
-{
- lguest_device_remove();
- free_interrupts();
- unmap_switcher();
-
- lguest_arch_host_fini();
-}
-/*:*/
-
-/*
- * The Host side of lguest can be a module. This is a nice way for people to
- * play with it.
- */
-module_init(init);
-module_exit(fini);
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");