/*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, and a
- * couple of non-obvious setup and teardown pieces which were implemented after
- * days of debugging pain. :*/
+ * Host to do something. This file also contains useful helper routines. :*/
#include <linux/module.h>
#include <linux/stringify.h>
#include <linux/stddef.h>
* easy.
*/
- /* We allocate an array of "struct page"s. map_vm_area() wants the
- * pages in this form, rather than just an array of pointers. */
+ /* 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) {
switcher_page[i] = virt_to_page(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. */
+ if (SWITCHER_ADDR + (TOTAL_SWITCHER_PAGES+1)*PAGE_SIZE > FIXADDR_START){
+ err = -ENOMEM;
+ printk("lguest: mapping switcher would thwack fixmap\n");
+ goto free_pages;
+ }
+
/* 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. */
+ * 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, VMALLOC_END);
+ VM_ALLOC, SWITCHER_ADDR, SWITCHER_ADDR
+ + (TOTAL_SWITCHER_PAGES+1) * PAGE_SIZE);
if (!switcher_vma) {
err = -ENOMEM;
printk("lguest: could not map switcher pages high\n");
/* 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 lguest *lg, void *b, unsigned long addr, unsigned bytes)
+void __lgread(struct lg_cpu *cpu, void *b, unsigned long addr, unsigned bytes)
{
- if (!lguest_address_ok(lg, addr, bytes)
- || copy_from_user(b, lg->mem_base + addr, bytes) != 0) {
+ 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(lg, "bad read address %#lx len %u", addr, bytes);
+ kill_guest(cpu, "bad read address %#lx len %u", addr, bytes);
}
}
-/* This is the write (copy into guest) version. */
-void __lgwrite(struct lguest *lg, unsigned long addr, const void *b,
+/* 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(lg, addr, bytes)
- || copy_to_user(lg->mem_base + addr, b, bytes) != 0)
- kill_guest(lg, "bad write address %#lx len %u", addr, 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);
}
/*:*/
* going around and around until something interesting happens. */
int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
{
- struct lguest *lg = cpu->lg;
-
/* We stop running once the Guest is dead. */
- while (!lg->dead) {
+ while (!cpu->lg->dead) {
/* First we run any hypercalls the Guest wants done. */
if (cpu->hcall)
do_hypercalls(cpu);
/* It's possible the Guest did a NOTIFY hypercall to the
* Launcher, in which case we return from the read() now. */
- if (lg->pending_notify) {
- if (put_user(lg->pending_notify, user))
+ if (cpu->pending_notify) {
+ if (put_user(cpu->pending_notify, user))
return -EFAULT;
- return sizeof(lg->pending_notify);
+ return sizeof(cpu->pending_notify);
}
/* Check for signals */
if (cpu->break_out)
return -EAGAIN;
- /* 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. */
+ /* 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. */
maybe_do_interrupt(cpu);
/* All long-lived kernel loops need to check with this horrible
/* Just make absolutely sure the Guest is still alive. One of
* those hypercalls could have been fatal, for example. */
- if (lg->dead)
+ if (cpu->lg->dead)
break;
/* If the Guest asked to be stopped, we sleep. The Guest's
lguest_arch_handle_trap(cpu);
}
- if (lg->dead == ERR_PTR(-ERESTART))
+ /* 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;
}
projects / linux-2.6-omap-h63xx.git / blobdiff