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path: root/drivers/lguest/core.c
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Diffstat (limited to 'drivers/lguest/core.c')
-rw-r--r--drivers/lguest/core.c87
1 files changed, 42 insertions, 45 deletions
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index efa202499e3..0bf1e4edf04 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -20,9 +20,9 @@
#include <asm/asm-offsets.h>
#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);
@@ -52,13 +52,21 @@ static __init int map_switcher(void)
* 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;
}
@@ -68,32 +76,29 @@ static __init int map_switcher(void)
* 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;
}
}
/*
- * 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: 0xFFC00000
- * (SWITCHER_ADDR). We might not get it in theory, but in practice
- * it's worked so far. The end address needs +1 because __get_vm_area
- * allocates an extra guard page, so we need space for that.
+ * Now we reserve the "virtual memory area" we want. We might
+ * not get it in theory, but in practice it's worked so far.
+ * The end address needs +1 because __get_vm_area allocates an
+ * extra guard page, so we need space for that.
*/
switcher_vma = __get_vm_area(TOTAL_SWITCHER_PAGES * PAGE_SIZE,
- VM_ALLOC, SWITCHER_ADDR, SWITCHER_ADDR
+ VM_ALLOC, switcher_addr, switcher_addr
+ (TOTAL_SWITCHER_PAGES+1) * PAGE_SIZE);
if (!switcher_vma) {
err = -ENOMEM;
@@ -103,12 +108,12 @@ static __init int map_switcher(void)
/*
* 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
+ * 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.
*/
- pagep = switcher_page;
+ pagep = lg_switcher_pages;
err = map_vm_area(switcher_vma, PAGE_KERNEL_EXEC, &pagep);
if (err) {
printk("lguest: map_vm_area failed: %i\n", err);
@@ -117,7 +122,7 @@ static __init int map_switcher(void)
/*
* Now the Switcher is mapped at the right address, we can't fail!
- * Copy in the compiled-in Switcher code (from <arch>_switcher.S).
+ * Copy in the compiled-in Switcher code (from x86/switcher_32.S).
*/
memcpy(switcher_vma->addr, start_switcher_text,
end_switcher_text - start_switcher_text);
@@ -133,8 +138,8 @@ free_pages:
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;
}
@@ -149,8 +154,8 @@ static void unmap_switcher(void)
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
@@ -225,13 +230,20 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
* eventfd (ie. the appropriate virtqueue thread)?
*/
if (!send_notify_to_eventfd(cpu)) {
- /* OK, we tell the main Laucher. */
+ /* OK, we tell the main Launcher. */
if (put_user(cpu->pending_notify, user))
return -EFAULT;
return sizeof(cpu->pending_notify);
}
}
+ /*
+ * 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;
@@ -246,13 +258,6 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
try_deliver_interrupt(cpu, irq, more);
/*
- * 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();
-
- /*
* Just make absolutely sure the Guest is still alive. One of
* those hypercalls could have been fatal, for example.
*/
@@ -313,7 +318,7 @@ static int __init init(void)
int err;
/* Lguest can't run under Xen, VMI or itself. It does Tricky Stuff. */
- if (paravirt_enabled()) {
+ if (get_kernel_rpl() != 0) {
printk("lguest is afraid of being a guest\n");
return -EPERM;
}
@@ -323,15 +328,10 @@ static int __init init(void)
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();
@@ -346,8 +346,6 @@ static int __init init(void)
free_interrupts:
free_interrupts();
-free_pgtables:
- free_pagetables();
unmap:
unmap_switcher();
out:
@@ -359,7 +357,6 @@ static void __exit fini(void)
{
lguest_device_remove();
free_interrupts();
- free_pagetables();
unmap_switcher();
lguest_arch_host_fini();
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 13:07:09 +0000