vmm(4): small cleanup in vm_rwregs.

Clarify error values and change a panic into a debug printf (which will
in turn just kill the VM).

diff --git a/sys/arch/amd64/amd64/vmm.c b/sys/arch/amd64/amd64/vmm.c
index 6cbad01..c405ade 100644 (file)
--- a/sys/arch/amd64/amd64/vmm.c
+++ b/sys/arch/amd64/amd64/vmm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vmm.c,v 1.210 2018/07/10 09:04:22 mlarkin Exp $       */
+/*     $OpenBSD: vmm.c,v 1.211 2018/07/11 12:45:01 mlarkin Exp $       */
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -653,13 +653,14 @@ vm_intr_pending(struct vm_intr_params *vip)
  *
  * Parameters:
  *   vrwp: Describes the VM and VCPU to get/set the registers from. The
- *   register values are returned here as well.
+ *    register values are returned here as well.
  *   dir: 0 for reading, 1 for writing
  *
  * Return values:
  *  0: if successful
- *  ENOENT: if the VM/VCPU defined by 'vgp' cannot be found
- *  EINVAL: if an error occured reading the registers of the guest
+ *  ENOENT: if the VM/VCPU defined by 'vrwp' cannot be found
+ *  EINVAL: if an error occured accessing the registers of the guest
+ *  EPERM: if the vm cannot be accessed from the calling process
  */
 int
 vm_rwregs(struct vm_rwregs_params *vrwp, int dir)
@@ -700,8 +701,10 @@ vm_rwregs(struct vm_rwregs_params *vrwp, int dir)
                return (dir == 0) ?
                    vcpu_readregs_svm(vcpu, vrwp->vrwp_mask, vrs) :
                    vcpu_writeregs_svm(vcpu, vrwp->vrwp_mask, vrs);
-       else
-               panic("unknown vmm mode");
+       else {
+               DPRINTF("%s: unknown vmm mode", __func__);
+               return (EINVAL);
+       }
 }
 
 /*