* the stack as well: virtual interrupts never do. */
set_guest_interrupt(lg, idt->a, idt->b, 0);
}
+
+ /* Every time we deliver an interrupt, we update the timestamp in the
+ * Guest's lguest_data struct. It would be better for the Guest if we
+ * did this more often, but it can actually be quite slow: doing it
+ * here is a compromise which means at least it gets updated every
+ * timer interrupt. */
+ write_timestamp(lg);
}
/*H:220 Now we've got the routines to deliver interrupts, delivering traps
/* 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;
}
/* 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