Detach emulated network devices if Netfront driver is enabled

Xen doesn't provide a way for a guest to decide which model of
the interface is selected in the VM configuration and therefore
there's no simple way for Netfront and emulated devices to co-
exist on the same system.  Emulated em(4) or re(4) drivers will
take over if xnf(4) driver is disabled or not compiled in.

Idea and OK reyk

3 files changed, 23 insertions, 22 deletions

diff --git a/sys/dev/pv/if_xnf.c b/sys/dev/pv/if_xnf.c
index 1852b7693c7..02761d8ff29 100644
--- a/sys/dev/pv/if_xnf.c
+++ b/sys/dev/pv/if_xnf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_xnf.c,v 1.5 2016/01/13 20:27:18 mikeb Exp $	*/
+/*	$OpenBSD: if_xnf.c,v 1.6 2016/01/15 14:27:08 mikeb Exp $	*/
 
 /*
  * Copyright (c) 2015, 2016 Mike Belopuhov
@@ -216,16 +216,11 @@ int
 xnf_match(struct device *parent, void *match, void *aux)
 {
 	struct xen_attach_args *xa = aux;
-	char type[64];
 
 	if (strcmp("vif", xa->xa_name))
 		return (0);
 
-	if (xs_getprop(xa, "type", type, sizeof(type)) == 0 &&
-	    ((strcmp("vif", type) == 0) || (strcmp("front", type) == 0)))
-		return (1);
-
-	return (0);
+	return (1);
 }
 
 void
@@ -291,6 +286,9 @@ xnf_attach(struct device *parent, struct device *self, void *aux)
 	ether_ifattach(ifp);
 
 	timeout_set(&sc->sc_rx_fill, xnf_rx_ring_fill, sc);
+
+	/* Kick out emulated em's and re's */
+	sc->sc_xen->sc_flags |= XSF_UNPLUG_NIC;
 }
 
 static int
diff --git a/sys/dev/pv/xen.c b/sys/dev/pv/xen.c
index 4ed8e2eba36..51b47eed52f 100644
--- a/sys/dev/pv/xen.c
+++ b/sys/dev/pv/xen.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: xen.c,v 1.26 2016/01/14 12:37:17 mikeb Exp $	*/
+/*	$OpenBSD: xen.c,v 1.27 2016/01/15 14:27:08 mikeb Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Belopuhov
@@ -146,10 +146,11 @@ xen_attach(struct device *parent, struct device *self, void *aux)
 	if (xs_attach(sc))
 		return;
 
-	xen_disable_emulated_devices(sc);
 
 	xen_probe_devices(sc);
 
+	xen_disable_emulated_devices(sc);
+
 	config_mountroot(self, xen_deferred);
 }
 
@@ -158,7 +159,7 @@ xen_deferred(struct device *self)
 {
 	struct xen_softc *sc = (struct xen_softc *)self;
 
-	if (!sc->sc_cbvec) {
+	if (!(sc->sc_flags & XSF_CBVEC)) {
 		DPRINTF("%s: callback vector hasn't been established\n",
 		    sc->sc_dev.dv_xname);
 		return;
@@ -496,7 +497,7 @@ xen_init_cbvec(struct xen_softc *sc)
 	DPRINTF("%s: registered callback IDT vector %d\n",
 	    sc->sc_dev.dv_xname, LAPIC_XEN_VECTOR);
 
-	sc->sc_cbvec = 1;
+	sc->sc_flags |= XSF_CBVEC;
 
 	return (0);
 }
@@ -1170,8 +1171,6 @@ xen_probe_devices(struct xen_softc *sc)
 #define XMI_UNPLUG_NIC		0x02
 #define XMI_UNPLUG_IDESEC	0x04
 
-int xen_disable_pv_ide, xen_disable_pv_idesec, xen_disable_pv_nic;
-
 void
 xen_disable_emulated_devices(struct xen_softc *sc)
 {
@@ -1179,18 +1178,17 @@ xen_disable_emulated_devices(struct xen_softc *sc)
 	ushort unplug = 0;
 
 	if (inw(XMI_PORT) != XMI_MAGIC) {
-		printf("%s: no magic!\n", sc->sc_dev.dv_xname);
+		printf("%s: failed to disable emulated devices\n",
+		    sc->sc_dev.dv_xname);
 		return;
 	}
-	if (xen_disable_pv_ide)
+	if (sc->sc_flags & XSF_UNPLUG_IDE)
 		unplug |= XMI_UNPLUG_IDE;
-	if (xen_disable_pv_idesec)
+	if (sc->sc_flags & XSF_UNPLUG_IDESEC)
 		unplug |= XMI_UNPLUG_IDESEC;
-	if (xen_disable_pv_nic)
+	if (sc->sc_flags & XSF_UNPLUG_NIC)
 		unplug |= XMI_UNPLUG_NIC;
-	if (unplug) {
+	if (unplug)
 		outw(XMI_PORT, unplug);
-		DPRINTF("%s: disabled emulated devices\n", sc->sc_dev.dv_xname);
-	}
 #endif	/* __i386__ || __amd64__ */
 }
diff --git a/sys/dev/pv/xenvar.h b/sys/dev/pv/xenvar.h
index 3f03673d93d..ef599b6e159 100644
--- a/sys/dev/pv/xenvar.h
+++ b/sys/dev/pv/xenvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: xenvar.h,v 1.19 2016/01/05 13:47:28 mikeb Exp $	*/
+/*	$OpenBSD: xenvar.h,v 1.20 2016/01/15 14:27:08 mikeb Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Belopuhov
@@ -61,7 +61,12 @@ struct xen_softc {
 
 	struct shared_info	*sc_ipg;	/* HYPERVISOR_shared_info */
 
-	int			 sc_cbvec;	/* callback was installed */
+	uint32_t		 sc_flags;
+#define  XSF_CBVEC		 0x0001
+#define  XSF_UNPLUG_NIC		 0x0002		/* disable emul. NICs */
+#define  XSF_UNPLUG_IDE		 0x0004		/* disable emul. primary IDE */
+#define  XSF_UNPLUG_IDESEC	 0x0008		/* disable emul. sec. IDE */
+
 	uint64_t		 sc_irq;	/* IDT vector number */
 	struct evcount		 sc_evcnt;	/* upcall counter */
 	SLIST_HEAD(, xen_intsrc) sc_intrs;