#include "lg.h"
unsigned long switcher_addr;
+struct page **lg_switcher_pages;
static struct vm_struct *switcher_vma;
-static struct page **switcher_page;
/* This One Big lock protects all inter-guest data structures. */
DEFINE_MUTEX(lguest_lock);
static __init int map_switcher(void)
{
int i, err;
- struct page **pagep;
/*
* Map the Switcher in to high memory.
* 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.
*/
- switcher_page = kmalloc(sizeof(switcher_page[0])*TOTAL_SWITCHER_PAGES,
- GFP_KERNEL);
- if (!switcher_page) {
+ lg_switcher_pages = kmalloc(sizeof(lg_switcher_pages[0])
+ * TOTAL_SWITCHER_PAGES,
+ GFP_KERNEL);
+ if (!lg_switcher_pages) {
err = -ENOMEM;
goto out;
}
* so we make sure they're zeroed.
*/
for (i = 0; i < TOTAL_SWITCHER_PAGES; i++) {
- switcher_page[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
- if (!switcher_page[i]) {
+ lg_switcher_pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
+ if (!lg_switcher_pages[i]) {
err = -ENOMEM;
goto free_some_pages;
}
}
- switcher_addr = SWITCHER_ADDR;
-
/*
- * First we check that the Switcher won't overlap the fixmap area at
- * the top of memory. It's currently nowhere near, but it could have
- * very strange effects if it ever happened.
+ * 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.
*/
- if (switcher_addr + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){
- err = -ENOMEM;
- printk("lguest: mapping switcher would thwack fixmap\n");
- goto free_pages;
- }
+ switcher_addr = FIXADDR_START - (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE;
/*
* Now we reserve the "virtual memory area" we want. We might
* 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 pages), and a pointer to our
- * array of struct pages. It increments that pointer, but we don't
- * care.
+ * array of struct pages.
*/
- pagep = switcher_page;
- err = map_vm_area(switcher_vma, PAGE_KERNEL_EXEC, &pagep);
+ err = map_vm_area(switcher_vma, PAGE_KERNEL_EXEC, lg_switcher_pages);
if (err) {
printk("lguest: map_vm_area failed: %i\n", err);
goto free_vma;
i = TOTAL_SWITCHER_PAGES;
free_some_pages:
for (--i; i >= 0; i--)
- __free_pages(switcher_page[i], 0);
- kfree(switcher_page);
+ __free_pages(lg_switcher_pages[i], 0);
+ kfree(lg_switcher_pages);
out:
return err;
}
vunmap(switcher_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(switcher_page[i], 0);
- kfree(switcher_page);
+ __free_pages(lg_switcher_pages[i], 0);
+ kfree(lg_switcher_pages);
}
/*H:032
if (err)
goto out;
- /* Now we set up the pagetable implementation for the Guests. */
- err = init_pagetables(switcher_page, SHARED_SWITCHER_PAGES);
- if (err)
- goto unmap;
-
/* We might need to reserve an interrupt vector. */
err = init_interrupts();
if (err)
- goto free_pgtables;
+ goto unmap;
/* /dev/lguest needs to be registered. */
err = lguest_device_init();
free_interrupts:
free_interrupts();
-free_pgtables:
- free_pagetables();
unmap:
unmap_switcher();
out:
{
lguest_device_remove();
free_interrupts();
- free_pagetables();
unmap_switcher();
lguest_arch_host_fini();