This bug has been there since day 1; addresses in the top guest
physical page weren't considered valid. You could map that page (the
check in check_gpte() is correct), but if a guest tried to put a
pagetable there we'd check that address manually when walking it, and
kill the guest.
Signed-off-by: Rusty Russell <[email protected]>
Cc: [email protected]
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index 7dc93aa004c8..312ffd3d0017 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -173,7 +173,7 @@ static void unmap_switcher(void)
bool lguest_address_ok(const struct lguest *lg,
unsigned long addr, unsigned long len)
{
- return (addr+len) / PAGE_SIZE < lg->pfn_limit && (addr+len >= addr);
+ return addr+len <= lg->pfn_limit * PAGE_SIZE && (addr+len >= addr);
}
/*