lguest: add infrastructure for userspace to deliver a trap to the guest.
This is required for instruction emulation to move to userspace.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index dcf9efd..be996d17 100644
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -243,6 +243,23 @@
return 0;
}
+/*L:053
+ * Deliver a trap: this is used by the Launcher if it can't emulate
+ * an instruction.
+ */
+static int trap(struct lg_cpu *cpu, const unsigned long __user *input)
+{
+ unsigned long trapnum;
+
+ if (get_user(trapnum, input) != 0)
+ return -EFAULT;
+
+ if (!deliver_trap(cpu, trapnum))
+ return -EINVAL;
+
+ return 0;
+}
+
/*L:040
* Once our Guest is initialized, the Launcher makes it run by reading
* from /dev/lguest.
@@ -487,6 +504,8 @@
return getreg_setup(cpu, input);
case LHREQ_SETREG:
return setreg(cpu, input);
+ case LHREQ_TRAP:
+ return trap(cpu, input);
default:
return -EINVAL;
}
diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h
index c4451eb..3c402b8 100644
--- a/include/linux/lguest_launcher.h
+++ b/include/linux/lguest_launcher.h
@@ -65,6 +65,7 @@
LHREQ_EVENTFD, /* + address, fd. */
LHREQ_GETREG, /* + offset within struct pt_regs (then read value). */
LHREQ_SETREG, /* + offset within struct pt_regs, value. */
+ LHREQ_TRAP, /* + trap number to deliver to guest. */
};
/*