Commit 56434622 authored by Rusty Russell's avatar Rusty Russell Committed by Linus Torvalds
Browse files

lguest: fix on Intel when KVM loaded (unhandled trap 13) 



When KVM is loaded, and hence VT set up, the vmcall instruction in an
lguest guest causes a #GP, not #UD.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ab2b7eba

drivers/lguest/x86/core.c

+10 −9
Original line number Diff line number Diff line
@@ -358,6 +358,16 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu) 
			if (emulate_insn(cpu))

				return;

		}

		/* If KVM is active, the vmcall instruction triggers a

		 * General Protection Fault.  Normally it triggers an

		 * invalid opcode fault (6): */

	case 6:

		/* We need to check if ring == GUEST_PL and

		 * faulting instruction == vmcall. */

		if (is_hypercall(cpu)) {

			rewrite_hypercall(cpu);

			return;

		}

		break;

	case 14: /* We've intercepted a Page Fault. */

		/* The Guest accessed a virtual address that wasn't mapped.
@@ -403,15 +413,6 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu) 
		 * up the pointer now to indicate a hypercall is pending. */

		cpu->hcall = (struct hcall_args *)cpu->regs;

		return;

	case 6:

		/* kvm hypercalls trigger an invalid opcode fault (6).

		 * We need to check if ring == GUEST_PL and

		 * faulting instruction == vmcall. */

		if (is_hypercall(cpu)) {

			rewrite_hypercall(cpu);

			return;

		}

		break;

	}



	/* We didn't handle the trap, so it needs to go to the Guest. */