Merge branch 'linux-2.6'

[linux-2.6] / drivers / lguest / interrupts_and_traps.c

diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
index 49787e964a0dfcae6b03fa044aaf2c0a03fd2a04..39731232d82770ecc3a4bb0d76cb27d4b9578621 100644 (file)
--- a/drivers/lguest/interrupts_and_traps.c
+++ b/drivers/lguest/interrupts_and_traps.c
@@ -195,13 +195,16 @@ static int has_err(unsigned int trap)
 /* deliver_trap() returns true if it could deliver the trap. */
 int deliver_trap(struct lguest *lg, unsigned int num)
 {
-       u32 lo = lg->idt[num].a, hi = lg->idt[num].b;
+       /* Trap numbers are always 8 bit, but we set an impossible trap number
+        * for traps inside the Switcher, so check that here. */
+       if (num >= ARRAY_SIZE(lg->idt))
+               return 0;
 
        /* Early on the Guest hasn't set the IDT entries (or maybe it put a
         * bogus one in): if we fail here, the Guest will be killed. */
-       if (!idt_present(lo, hi))
+       if (!idt_present(lg->idt[num].a, lg->idt[num].b))
                return 0;
-       set_guest_interrupt(lg, lo, hi, has_err(num));
+       set_guest_interrupt(lg, lg->idt[num].a, lg->idt[num].b, has_err(num));
        return 1;
 }
 
@@ -267,8 +270,11 @@ void pin_stack_pages(struct lguest *lg)
        /* Depending on the CONFIG_4KSTACKS option, the Guest can have one or
         * two pages of stack space. */
        for (i = 0; i < lg->stack_pages; i++)
-               /* The stack grows *upwards*, hence the subtraction */
-               pin_page(lg, lg->esp1 - i * PAGE_SIZE);
+               /* The stack grows *upwards*, so the address we're given is the
+                * start of the page after the kernel stack.  Subtract one to
+                * get back onto the first stack page, and keep subtracting to
+                * get to the rest of the stack pages. */
+               pin_page(lg, lg->esp1 - 1 - i * PAGE_SIZE);
 }
 
 /* Direct traps also mean that we need to know whenever the Guest wants to use